Display panel, preparation method thereof and display device

Abstract

The application discloses a display panel, a preparation method thereof and a display device. The display panel comprises a plurality of light-emitting areas, each of which comprises a first color light-emitting unit and other color light-emitting units, each of which comprises a hole injection layer; wherein in the same light-emitting area, the minimum thickness of the hole injection layer of the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layer of the other color light-emitting units. The scheme disclosed by the application can effectively prevent the color deviation problem caused by the lateral leakage between the light-emitting units.

Description

Technical Field

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

[0002] With the development of display technology, organic light-emitting diode (OLED) display panels have become an important display technology due to their advantages such as self-illumination, fast response, wide viewing angle, high brightness, vibrant colors, and thinness.

[0003] Typically, an OLED display panel comprises multiple light-emitting units, each including an organic light-emitting element (OLED), a thin-film transistor (TFT), and other structures. The OLED includes an anode, a cathode, and a light-emitting layer between the anode and cathode. It may further include at least one of the following layers: a hole injection layer, a hole transport layer, an electron injection layer, or an electron transport layer. However, because some of these layers are continuous structures, and the hole injection layer has excellent conductivity, lateral current conduction occurs when an electrical signal is supplied to the OLED display panel. This leads to leakage current and causes color shift issues in other areas. Summary of the Invention

[0004] This invention provides a display panel and its manufacturing method, as well as a display device, which can effectively prevent color shift caused by lateral leakage between light-emitting units.

[0005] In a first aspect, embodiments of the present invention provide a display panel including a plurality of light-emitting regions, each light-emitting region including a first color light-emitting unit and other color light-emitting units, and each light-emitting unit including a hole injection layer;

[0006] Within the same light-emitting region, the minimum thickness of the hole injection layer of the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layer of other color light-emitting units.

[0007] In the display panel described above, optionally, the hole injection layer of the first color light-emitting unit has a uniform thickness; or...

[0008] The thickness of the hole injection layer of the first color light-emitting unit gradually decreases from the center of the first color light-emitting unit towards the edge; or...

[0009] The hole injection layer of the first color light-emitting unit includes a first region and a second region surrounding the first region. The hole injection layer of the first color light-emitting unit in the first region has a uniform thickness, and the hole injection layer of the first color light-emitting unit in the second region gradually decreases from the center of the first color light-emitting unit toward the edge.

[0010] In the above display panel, optionally, in the same light-emitting area, the thickness of the hole injection layer of other color light-emitting units located around the first color light-emitting unit gradually decreases from the center of the first color light-emitting unit toward the edge.

[0011] Optionally, each light-emitting unit of the display panel described above may further include a first electrode, a hole transport layer, a light-emitting layer and a second electrode stacked along the light-emitting direction of the display panel, with the hole injection layer located between the first electrode and the hole transport layer.

[0012] In the same light-emitting region, the thickness of the hole transport layer of the first color light-emitting unit is equal to the thickness of the hole transport layer of the other color light-emitting units; or, in the same light-emitting region, the minimum thickness of the hole transport layer of the first color light-emitting unit is greater than or equal to the maximum thickness of the hole transport layer of the other color light-emitting units.

[0013] Preferably, the hole transport layer of the first color light-emitting unit has a uniform thickness; or, the thickness of the hole transport layer of the first color light-emitting unit gradually decreases from the center of the first color light-emitting unit toward the edge; or, the hole transport layer of the first color light-emitting unit includes a third region and a fourth region surrounding the third region, wherein the hole transport layer of the first color light-emitting unit in the third region has a uniform thickness, and the thickness of the hole transport layer of the first color light-emitting unit in the fourth region gradually decreases from the center of the first color light-emitting unit toward the edge.

[0014] Preferably, in the same light-emitting region, the thickness of the hole transport layer of other color light-emitting units located around the first color light-emitting unit gradually decreases from the center of the first color light-emitting unit toward the edge.

[0015] In the display panel described above, optionally, each light-emitting area includes a first color light-emitting unit, a second color light-emitting unit, and a third color light-emitting unit; wherein, in a first direction and / or a second direction, the first color light-emitting unit is located between the second color light-emitting unit and the third color light-emitting unit; or...

[0016] Each luminescent region includes one first-color luminescent unit, two second-color luminescent units, and two third-color luminescent units; wherein, in a first direction, the first-color luminescent unit is located between the two second-color luminescent units; in a second direction, the first-color luminescent unit is located between the two third-color luminescent units; the first direction intersects with the second direction.

[0017] Optionally, in the display panel described above, the first color light-emitting unit emits blue light, the second color light-emitting unit emits green light, and the third color light-emitting unit emits red light; or...

[0018] The first color light-emitting unit emits blue light, the second color light-emitting unit emits red light, and the third color light-emitting unit emits green light.

[0019] Secondly, embodiments of the present invention also provide a display device, which includes a display panel having any of the optional methods described in the first aspect.

[0020] Thirdly, embodiments of the present invention also provide a method for manufacturing a display panel, used to manufacture a display panel according to any of the optional methods of the first aspect described above. The display panel includes multiple light-emitting regions, each light-emitting region including a first color light-emitting unit and other color light-emitting units. The method for manufacturing the display panel includes:

[0021] A first electrode, a hole injection layer, a hole transport layer, a light-emitting layer, and a second electrode are formed on one side of a substrate. In the same light-emitting region, the minimum thickness of the hole injection layer of the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layer of other color light-emitting units.

[0022] The method for forming a hole injection layer on the side of the first electrode away from the substrate includes:

[0023] Based on the size of the light-emitting area and the opening width W of the mask, a first distance H1 and a second distance H2 are set, wherein the first distance H1 is the vertical distance from the surface of the display panel to be vaporized to the mask, and the second distance H2 is the vertical distance from the mask to the evaporation source.

[0024] The position of the mask plate is controlled based on the first distance H1 and the second distance H2;

[0025] Turn on the evaporation source and deposit a hole injection layer on the first electrode.

[0026] In the above method for fabricating the display panel, optionally, for any light-emitting region, the thickness of the hole injection layer at position m is...

[0027] Where m represents any position in the air injection layer; θ0 is the angle between the line connecting the midpoint of the evaporation source and the edge of the luminous region and the plane containing the evaporation source; θ m Let θ be the angle between the line connecting the midpoint of the evaporation source and position m and the plane containing the evaporation source; H(θ) is the function relating the evaporation rate of the evaporation source to the angle θ.

[0028] In the above method for manufacturing a display panel, optionally, the opening width W of the mask is greater than or equal to the effective pixel width of the first color light-emitting unit, and less than or equal to the sum of the effective pixel width of the first color light-emitting unit and the width of the pixel limiting layer located on both sides of the first color light-emitting unit.

[0029] Preferably, the width of the light-emitting area is

[0030] This invention provides a display panel, its manufacturing method, and a display device. By dividing the display panel into multiple light-emitting areas and designing the morphology of the hole injection layer for different color light-emitting units within the same light-emitting area, the minimum thickness of the hole injection layer for the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layer for other color light-emitting units. Compared to the conventional display panel with equal-thickness hole injection layers, in this invention, because the minimum thickness of the hole injection layer for the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layer for other color light-emitting units within the same light-emitting area, the lateral resistance of the hole injection layer for other color light-emitting units is greater than that of the first color light-emitting unit. With the cross voltage of the display panel remaining constant, the current corresponding to other color light-emitting units is less than that corresponding to the first color light-emitting unit. This reduces the common layer voltage corresponding to other color light-emitting units, potentially preventing them from reaching the turn-on voltage and thus preventing them from illuminating. This effectively prevents lateral leakage between adjacent color light-emitting units, solving problems such as color crosstalk and decreased contrast in the display panel, and improving the display effect. Attached Figure Description

[0031] Figure 1 This is a top view structural diagram of a display panel provided in an embodiment of the present invention;

[0032] Figure 2 This is a top view structural diagram of a light-emitting area provided in an embodiment of the present invention;

[0033] Figure 3 This is a schematic cross-sectional view of a light-emitting region provided in an embodiment of the present invention;

[0034] Figure 4 yes Figure 3 The diagram shows a schematic of the hole injection layer membrane.

[0035] Figure 5 This is a schematic cross-sectional view of another light-emitting region provided in an embodiment of the present invention;

[0036] Figure 6 yes Figure 5 The diagram shows a schematic of the hole injection layer membrane.

[0037] Figure 7 This is a cross-sectional structural diagram of another light-emitting region provided in an embodiment of the present invention;

[0038] Figure 8 yes Figure 7 The diagram shows a schematic of the hole injection layer membrane.

[0039] Figure 9 This is a top view of another light-emitting area provided in an embodiment of the present invention;

[0040] Figure 10 This is a schematic flowchart of a method for manufacturing a display panel according to an embodiment of the present invention;

[0041] Figure 11 This is a schematic flowchart of a method for preparing a hole injection layer according to an embodiment of the present invention;

[0042] Figure 12(a) is a diagram showing the relationship between the morphology of an evaporation source, a mask, and a hole injection layer provided in an embodiment of the present invention.

[0043] Figure 12(b) is a diagram showing the relationship between the morphology of another evaporation source, mask, and hole injection layer provided in an embodiment of the present invention.

[0044] Figure 12(c) is a diagram showing the relationship between the morphology of the evaporation source, the mask plate, and the hole injection layer provided in another embodiment of the present invention.

[0045] Figure 13 This is a schematic diagram illustrating the calculation of the thickness of the hole injection layer at position m, provided in an embodiment of the present invention. Detailed Implementation

[0046] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0047] Furthermore, the accompanying drawings and descriptions of the embodiments are illustrative rather than restrictive. The same reference numerals denote the same elements throughout the specification. Additionally, for ease of understanding and description, the thicknesses of some layers, films, panels, regions, etc., may be exaggerated in the drawings. It is also understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, the element may be directly on the other element or there may be an intermediate element present. Furthermore, "on" means positioning the element on or below another element, but does not inherently mean positioning it on top of another element according to the direction of gravity. For ease of understanding, elements are always drawn on top of other elements in the accompanying drawings of this invention.

[0048] In addition, unless explicitly stated otherwise, the words “including” and variations such as “contains” or “has” will be understood to imply the inclusion of the element, but not to exclude any other element.

[0049] It should also be noted that, in the embodiments of the present invention, "and / or" refers to any and all combinations including one or more of the related listed items. Various components are described using terms such as "first," "second," and "third" in the embodiments of the present invention, but these components should not be limited by these terms. These terms are only used to distinguish one component from another. Furthermore, unless the context clearly indicates otherwise, the singular forms "a," "an," and "the" are also intended to include the plural forms.

[0050] When an embodiment can be implemented differently, the specific process sequence may be performed differently than the described sequence. For example, two consecutively described processes may be performed substantially at the same time or in the reverse order of their description.

[0051] Existing OLED display panels include multiple light-emitting units, each comprising structures such as an organic light-emitting element (OLED) and a thin-film transistor (TFT). For example, an OLED may include an anode, a cathode, and a light-emitting layer between the anode and cathode. Holes injected from the anode and electrons injected from the cathode recombine in the light-emitting layer to generate excitons, thereby causing the light-emitting layer to emit light. OLEDs may also further include organic functional films such as a hole injection layer. In the manufacturing process of OLEDs, a evaporation method is typically used to form the hole injection layer. Multiple light-emitting units sharing a single hole injection layer simplifies the manufacturing process and reduces production costs.

[0052] Assume that each pixel unit of the display panel includes three light-emitting units, and each light-emitting unit includes an organic light-emitting element (OLED). This OLED includes structures such as an anode, a cathode, a light-emitting layer, and a hole injection layer. The hole injection layer is a continuous film layer located within each light-emitting unit and between adjacent light-emitting units; that is, the OLEDs of the three light-emitting units share the hole injection layer. For example, the first color light-emitting unit can emit blue light, the second color light-emitting unit can emit green light, and the third color light-emitting unit can emit red light.

[0053] When a voltage is applied to the first color light-emitting unit while no voltage is applied to the second and third color light-emitting units, theoretically only the first color light-emitting unit should emit blue light, while the second and third color light-emitting units should not emit light. However, because the lateral transport rate of charge carriers in the hole injection layer is typically high, under the influence of the voltage difference, charge carriers in the hole injection layer located in the first color light-emitting unit will laterally transport to the adjacent hole injection layers located in the second and third color light-emitting units, causing the second color light-emitting unit to emit green light and the third color light-emitting unit to emit red light. This lateral transport of charge carriers in the hole injection layer within adjacent light-emitting units can cause color crosstalk and decreased contrast in the display panel, preventing it from meeting normal display requirements and affecting its display performance.

[0054] To address the aforementioned problems, embodiments of the present invention provide a display panel and its manufacturing method, as well as a display device. By dividing the display area into multiple light-emitting regions and designing the morphology of the hole injection layer for different color light-emitting units within the same light-emitting region, the minimum thickness of the hole injection layer for the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layer for the other color light-emitting units. Compared to the conventional display panel with equal-thickness hole injection layers, in the same light-emitting region of the present invention, because the minimum thickness of the hole injection layer for the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layer for the other color light-emitting units, the lateral resistance of the hole injection layer for the other color light-emitting units is greater than that of the first color light-emitting unit. With the cross-voltage of the display panel remaining constant, the current corresponding to the other two color light-emitting units is less than the current corresponding to the first color light-emitting unit. Therefore, the common layer voltage corresponding to the other two color light-emitting units is reduced, and may even fail to reach the turn-on voltage at that location, preventing the other color light-emitting units from being turned on. This effectively prevents lateral leakage between adjacent color light-emitting units, solving problems such as color crosstalk and decreased contrast in the display panel, and improving the display effect.

[0055] The structure, technical effects, and manufacturing methods of the display panel are described in detail below.

[0056] Furthermore, the following embodiments use a rectangular display panel as an example. In practical applications, the display panel can also be a regular or irregular shape such as a circle or polygon. This invention does not impose any specific limitations on this.

[0057] Figure 1 This diagram illustrates a top view of a display panel according to an embodiment of the present invention. Figure 1As shown, the display panel includes a display area AA and a non-display area NAA adjacent to the display area AA. The display area AA is the area of ​​the display panel used to display images and includes multiple light-emitting areas 10; wherein, the light-emitting areas 10 can be arranged in an array. The non-display area NAA surrounds the display area and typically includes peripheral driving elements, peripheral traces, and a fan-out area. Optionally, in order to achieve a narrow bezel, if the display panel is a flexible display panel, the non-display area NAA may also include a bending area and a non-bending area. The bending area is located between the non-bending area and the display area AA, and the bezel area of ​​the display panel (located in the non-display area) can be folded back to the back of the display panel.

[0058] The light-emitting region 10 may include light-emitting units of at least three colors. For example, the light-emitting region 10 includes a first-color light-emitting unit and other-color light-emitting units. Preferably, the other-color light-emitting units may be a second-color light-emitting unit different from the first-color light-emitting unit, or a third-color light-emitting unit different from the first-color light-emitting unit, or a second-color light-emitting unit and a third-color light-emitting unit different from the first-color light-emitting unit. Each light-emitting unit includes a hole injection layer; wherein, within the same light-emitting region, the minimum thickness of the hole injection layer of the first-color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layers of the other two-color light-emitting units.

[0059] It should be noted that the hole injection layer of the light-emitting unit involved in this invention includes: a hole injection layer corresponding to the opening region of the light-emitting unit and the pixel defining layer region around the opening region. The hole injection layers between adjacent light-emitting units are connected to form a planar film layer.

[0060] In the first exemplary embodiment, Figure 2 This diagram shows a top view of a light-emitting area according to an embodiment of the present invention. Figure 3 A cross-sectional structural diagram of a light-emitting region provided by an embodiment of the present invention is shown. For example... Figure 2 and Figure 3 As shown, each light-emitting region 10 includes a first-color light-emitting unit 11, a second-color light-emitting unit 12, and a third-color light-emitting unit 13. Any two adjacent light-emitting units are separated by a pixel-defining layer 104. In a first direction and / or a second direction, the first-color light-emitting unit 11 is located between the second-color light-emitting unit 12 and the third-color light-emitting unit 13. The first direction intersects the second direction. The first direction can be horizontal, vertical, or oblique, etc., and the second direction can be vertical, horizontal, or oblique, etc. That is, the arrangement of the first-color light-emitting unit 11 and other color light-emitting units only needs to satisfy that they are located around the first-color light-emitting unit in the same light-emitting region. For example, the first-color light-emitting unit 11 is located between the second-color light-emitting unit 12 and the third-color light-emitting unit 13.

[0061] Along the light emission direction of the display panel, the first color light-emitting unit 11 includes a first electrode stacked on the substrate 100. Figure 2 (Not shown in the drawing), hole injection layer 111, light-emitting layer 112, and second electrode ( Figure 2 (Not shown in the drawing); the second color light-emitting unit 12 includes a first electrode stacked on the substrate 100 (not shown in the drawing); Figure 2 (Not shown in the drawing), hole injection layer 121, light-emitting layer 122, and second electrode ( Figure 2 (Not shown in the drawing); the third color light-emitting unit 13 includes a first electrode stacked on the substrate 100 (not shown in the drawing); Figure 2 (Not shown in the drawing), hole injection layer 131, light-emitting layer 132, and second electrode ( Figure 2 (Not shown in the drawing).

[0062] The substrate 100 can be flexible, and thus stretchable, foldable, bendable, or rollable, so that the display panel can be stretchable, foldable, bendable, or rollable. The substrate 100 can be formed of any suitable insulating material that is flexible. The substrate 100 serves to block moisture and oxygen, prevent moisture or impurities from diffusing through the substrate, and provide a flat surface on the upper surface of the substrate.

[0063] Figure 4 It shows Figure 3 The schematic diagram of the hole injection layer shown is as follows: Figure 4 As shown, the hole injection layer 111 of the first color light-emitting unit 11, the hole injection layer 121 of the second color light-emitting unit 12, and the hole injection layer 131 of the third color light-emitting unit 13 are continuous film layers and can be formed in a single process. Figure 3 and Figure 4 In this design, the hole injection layer 111 of the first color light-emitting unit 11 has a uniform thickness, and the thickness of the hole injection layer 111 of the first color light-emitting unit 11 is greater than the maximum thickness of the hole injection layers of the other two color light-emitting units. Typically, for every reduction in the thickness of the hole injection layer... The turn-on voltage at this location increases by 0.05V-0.1V, and the lateral resistance also increases accordingly. Therefore, when the hole injection layer thickness of the second color light-emitting unit 12 and the third color light-emitting unit 13 is less than the hole injection layer 111 of the first color light-emitting unit 11, under the condition that the cross voltage of the display panel remains unchanged, the current corresponding to the second color light-emitting unit 12 and the third color light-emitting unit 13 is less than the current corresponding to the first color light-emitting unit 11, and the common layer voltage corresponding to the second color light-emitting unit 12 and the third color light-emitting unit 13 decreases, thereby effectively preventing lateral leakage between adjacent color light-emitting units. Furthermore, the increase in the turn-on voltage of the second color light-emitting unit 12 and the third color light-emitting unit 13 may even cause the common layer voltage corresponding to the second color light-emitting unit 12 and the third color light-emitting unit 13 to be less than the turn-on voltage at this location, preventing the second color light-emitting unit 12 and the third color light-emitting unit 13 from being turned on. This solves problems such as color crosstalk and decreased contrast in the display panel, improving the display effect of the display panel.

[0064] Continue to refer to Figure 3 and Figure 4 Optionally, the thickness of the hole injection layer of other color light-emitting units located around the first color light-emitting unit 11 gradually decreases from the center of the first color light-emitting unit 11 towards the edge. That is, the thickness of the hole injection layer 121 of the second color light-emitting unit 12 and the thickness of the hole injection layer 131 of the third color light-emitting unit 13 gradually decrease from the center of the first color light-emitting unit 11 towards the edge. In this way, the lateral resistance of the second color light-emitting unit 12 near the first color light-emitting unit increases, and the lateral resistance of the third color light-emitting unit 13 near the first color light-emitting unit further increases, preventing lateral leakage between different color light-emitting units in the same light-emitting area 10. At the same time, the lateral resistance of other positions of the second color light-emitting unit 12 and the lateral resistance of other positions of the third color light-emitting unit 13 also increase, preventing lateral leakage between adjacent light-emitting areas.

[0065] In one embodiment, Figure 5 This diagram shows a cross-sectional view of another light-emitting region provided in an embodiment of the present invention. Figure 6 It shows Figure 5 The diagram shows a schematic of the hole injection layer membrane. (Compared to...) Figure 3 and Figure 4 The difference lies in that the thickness of the hole injection layer 111 of the first color light-emitting unit 11 gradually decreases from the center of the first color light-emitting unit 11 towards the edge, and the thickness of the hole injection layer 111 at the edge of the first color light-emitting unit 11 is greater than or equal to the maximum thickness of the hole injection layer of the other two color light-emitting units. Typically, the thickness of the hole injection layer decreases by [percentage missing]. The turn-on voltage at this location increases by 0.05V-0.1V, and the lateral resistance also increases accordingly. Therefore, when the maximum thickness of the hole injection layer of the second color light-emitting unit 12 and the third color light-emitting unit 13 is less than the minimum thickness of the hole injection layer 111 of the first color light-emitting unit 11, under the condition that the cross voltage of the display panel remains unchanged, the current corresponding to the second color light-emitting unit 12 and the third color light-emitting unit 13 is less than the current corresponding to the first color light-emitting unit 11, and the common layer voltage corresponding to the second color light-emitting unit 12 and the third color light-emitting unit 13 decreases, thereby effectively preventing lateral leakage between adjacent color light-emitting units. Furthermore, the increase in the turn-on voltage of the second color light-emitting unit 12 and the third color light-emitting unit 13 may even cause the common layer voltage corresponding to the second color light-emitting unit 12 and the third color light-emitting unit 13 to be less than the turn-on voltage at this location, preventing the second color light-emitting unit 12 and the third color light-emitting unit 13 from being turned on. This solves problems such as color crosstalk and decreased contrast in the display panel, improving the display effect of the display panel.

[0066] Continue to refer to Figure 5 and Figure 6 Optionally, the thickness of the hole injection layer of other color light-emitting units located around the first color light-emitting unit 11 gradually decreases from the center of the first color light-emitting unit 11 towards the edge. That is, the thickness of the hole injection layer 121 of the second color light-emitting unit 12 and the thickness of the hole injection layer 131 of the third color light-emitting unit 13 gradually decrease from the center of the first color light-emitting unit 11 towards the edge. In this way, the lateral resistance of the second color light-emitting unit 12 near the first color light-emitting unit increases, and the lateral resistance of the third color light-emitting unit 13 near the first color light-emitting unit further increases, preventing lateral leakage between different color light-emitting units in the same light-emitting area 10, and further improving the display effect of the display panel. At the same time, the lateral resistance of other positions of the second color light-emitting unit 12 and the lateral resistance of other positions of the third color light-emitting unit 13 also increase, preventing lateral leakage between adjacent light-emitting areas. Figure 5 and Figure 6 As shown, the thickness of the hole injection layer has a continuous and smooth transition, which can reduce the difficulty of the process and facilitate mass production.

[0067] It is understandable that the thinner the hole injection layer, the greater the lateral resistance at that location, and the smaller the corresponding common layer voltage. Considering the difficulty of film fabrication and the reliability of preventing lateral leakage between adjacent color emitting units, the thickness of the hole injection layer can be reasonably designed. For example, the ratio of the thickness D1 of the maximum hole injection layer 111 at the center of the first color emitting unit 11 to the thickness D2 of the minimum hole injection layer 121 at the edge of the second color emitting unit 12 or the thickness D2 of the minimum hole injection layer 131 at the edge of the third color emitting unit 13 is greater than or equal to 2. In this way, the hole injection layer can be fabricated more easily, while ensuring the reliability of preventing lateral leakage between adjacent color emitting units.

[0068] In one embodiment, Figure 7 This diagram shows a cross-sectional view of another light-emitting region provided by an embodiment of the present invention. Figure 8 It shows Figure 7 The diagram shows a schematic of the hole injection layer membrane. (Compared to...) Figure 3 and Figure 4 The difference lies in that the hole injection layer 111 of the first color light-emitting unit 11 includes a first region A and a second region B surrounding the first region A. The hole injection layer 111 of the first color light-emitting unit 11 in the first region A has a uniform thickness, while the thickness of the hole injection layer 111 of the first color light-emitting unit 11 in the second region B gradually decreases from the center of the first color light-emitting unit 11 towards the edge. The minimum thickness of the hole injection layer 111 at the edge of the first color light-emitting unit 11 is greater than or equal to the maximum thickness of the hole injection layer of the other two color light-emitting units. Typically, the thickness of the hole injection layer decreases by [percentage missing]. The turn-on voltage at this location increases by 0.05V-0.1V, and the lateral resistance also increases accordingly. Therefore, when the maximum thickness of the hole injection layer of the second color light-emitting unit 12 and the third color light-emitting unit 13 is less than the minimum thickness of the hole injection layer 111 of the first color light-emitting unit 11, under the condition that the cross voltage of the display panel remains unchanged, the current corresponding to the second color light-emitting unit 12 and the third color light-emitting unit 13 is less than the current corresponding to the first color light-emitting unit 11, and the common layer voltage corresponding to the second color light-emitting unit 12 and the third color light-emitting unit 13 decreases, thereby effectively preventing lateral leakage between adjacent color light-emitting units. Furthermore, the increase in the turn-on voltage of the second color light-emitting unit 12 and the third color light-emitting unit 13 may even cause the common layer voltage corresponding to the second color light-emitting unit 12 and the third color light-emitting unit 13 to be less than the turn-on voltage at this location, preventing the second color light-emitting unit 12 and the third color light-emitting unit 13 from being turned on. This solves problems such as color crosstalk and decreased contrast in the display panel, improving the display effect of the display panel.

[0069] Optionally, the first region A can correspond to the opening region of the first color light-emitting unit 11, and the second region B can correspond to the non-opening region surrounding the opening region of the first color light-emitting unit 11; or, the first region A is slightly larger than the opening region of the first color light-emitting unit 11, and the second region B is slightly smaller than the non-opening region surrounding the opening region of the first color light-emitting unit 11; or, the first region A is slightly smaller than the opening region of the first color light-emitting unit 11, and the second region B is slightly larger than the non-opening region surrounding the opening region of the first color light-emitting unit 11. Of course, both the first region and the second region can be located within the opening region, meaning that the thickness of the hole injection layer within the opening region can be uniform in the central region and gradually decrease in thickness towards the center from the surrounding regions.

[0070] Continue to refer to Figure 7 and Figure 8 Optionally, the thickness of the hole injection layer of other color light-emitting units located around the first color light-emitting unit 11 gradually decreases from the center of the first color light-emitting unit 11 towards the edge. That is, the thickness of the hole injection layer 121 of the second color light-emitting unit 12 and the thickness of the hole injection layer 131 of the third color light-emitting unit 13 gradually decrease from the center of the first color light-emitting unit 11 towards the edge. In this way, the lateral resistance of the second color light-emitting unit 12 near the first color light-emitting unit increases, and the lateral resistance of the third color light-emitting unit 13 near the first color light-emitting unit further increases, preventing lateral leakage between different color light-emitting units in the same light-emitting area 10, and further improving the display effect of the display panel. At the same time, the lateral resistance of other positions of the second color light-emitting unit 12 and the lateral resistance of other positions of the third color light-emitting unit 13 also increase, preventing lateral leakage between adjacent light-emitting areas.

[0071] It should also be noted that each light-emitting unit 10 further includes a hole transport layer (not shown in the figure) disposed between the first electrode and the hole injection layer. The structure of the hole transport layer can be similar to that of the hole injection layer described in any of the above implementations, and can also prevent lateral leakage between adjacent color light-emitting units, thus solving problems such as color crosstalk and contrast reduction in the display panel. For the sake of simplicity, it will not be described in detail here.

[0072] Specifically, within the same light-emitting region, the first color light-emitting unit and other color light-emitting units (in this embodiment, the other color light-emitting units are the second color light-emitting unit and the third color light-emitting unit) have the following characteristics: Within the same light-emitting region, the thickness of the hole transport layer of the first color light-emitting unit is equal to the thickness of the hole transport layers of the other two color light-emitting units; or, within the same light-emitting region, the minimum thickness of the hole transport layer of the first color light-emitting unit is greater than or equal to the maximum thickness of the hole transport layers of the other two color light-emitting units.

[0073] The hole transport layer of the first color light-emitting unit has a uniform thickness; or, the thickness of the hole transport layer of the first color light-emitting unit gradually decreases from the center of the first color light-emitting unit toward the edge; or, the hole transport layer of the first color light-emitting unit includes a third region and a fourth region surrounding the third region, wherein the hole transport layer of the first color light-emitting unit in the third region has a uniform thickness, and the thickness of the hole transport layer of the first color light-emitting unit in the fourth region gradually decreases from the center of the first color light-emitting unit toward the edge.

[0074] Within the same luminescent region, the thickness of the hole transport layer of other color luminescent units located around the first color luminescent unit gradually decreases from the center of the first color luminescent unit toward the edge.

[0075] In one embodiment, the morphology of the hole transport layer can be the same as that of the hole injection layer. Thus, the hole transport layer and the hole injection layer can be formed using the same process (e.g., sharing a single mask), which reduces the manufacturing complexity of the display panel and lowers production costs.

[0076] In embodiments of the present invention, the first electrode is typically an anode, and the second electrode is typically a cathode.

[0077] In the second exemplary embodiment, the first color light-emitting unit and other color light-emitting units in the same light-emitting area, in this embodiment, the other color light-emitting units are the second color light-emitting unit and the third color light-emitting unit.

[0078] Figure 9 This diagram shows a top view of another light-emitting area provided in an embodiment of the present invention, as shown below. Figure 9 As shown, each luminescent region 10 includes one first-color luminescent unit 11, two second-color luminescent units 12, and two third-color luminescent units 13; wherein, in the first direction X, the first-color luminescent unit 11 is located between the two second-color luminescent units 12; in the second direction Y, the first-color luminescent unit 11 is located between the two third-color luminescent units 13; the first direction X intersects the second direction Y. For example, the first direction X and the second direction Y are perpendicular to each other.

[0079] It should be noted that in the second exemplary embodiment, the structure of the hole injection layer of the light-emitting unit is similar to that in the first exemplary embodiment described above, and will not be repeated here for the sake of brevity.

[0080] Among blue, red, and green light, the human eye is least sensitive to blue light and most sensitive to green light. Furthermore, because the transverse voltage of the blue light-emitting unit is the highest, it is most prone to lateral leakage. Therefore, the placement of different colored light-emitting units can be designed by combining the power consumption and lifespan of different colors with the human eye's sensitivity to light. Specifically, the first colored light-emitting unit emits blue light, the second emits green light, and the third emits red light; or, the first colored light-emitting unit emits blue light, the second emits red light, and the third emits green light. Placing the red / green and green / red light-emitting units at the edges of the emitting area can minimize color shift caused by lateral leakage between the units.

[0081] Assumption Figure 3 The hole injection layer thickness at the edge of the light-emitting area of ​​the display panel shown is HI2, while the hole injection layer thickness of existing display panels is HI1. HI2 is thinner than HI1. Table 1 shows the turn-on voltage for these two types of display panels.

[0082] Table 1 Comparison of the turn-on voltage of the display panel provided by this invention and existing display panels

[0083]

[0084] As can be seen from Table 1, the display panel provided by the present invention designs the morphology of the hole injection layer of different color light-emitting units in the light-emitting area, thereby increasing the turn-on voltage of different color light-emitting units. When the cross voltage of the display panel remains unchanged, the current corresponding to other color light-emitting units is less than the current corresponding to the first color light-emitting unit, and the common layer voltage corresponding to other color light-emitting units is reduced. It may even cause the common layer voltage corresponding to other color light-emitting units to be less than the turn-on voltage at that position, so other color light-emitting units will not be turned on. This solves the problems of color crosstalk and decreased contrast in the display panel and improves the display effect of the display panel.

[0085] This invention provides a display panel including multiple light-emitting regions. Each light-emitting region includes a first color light-emitting unit and other color light-emitting units, including a second color light-emitting unit and a third color light-emitting unit. Each light-emitting unit includes a hole injection layer; wherein, within the same light-emitting region, the minimum thickness of the hole injection layer of the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layers of the other two color light-emitting units. By dividing the display region into multiple light-emitting regions and designing the morphology of the hole injection layers of different color light-emitting units within the same light-emitting region, the minimum thickness of the hole injection layer of the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layers of the other two color light-emitting units. Compared with the conventional display panel with equal-thickness hole injection layers, in the same light-emitting region of this invention, because the minimum thickness of the hole injection layer of the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layers of the other two color light-emitting units, the lateral resistance of the hole injection layers of the other two color light-emitting units is greater than the lateral resistance of the hole injection layer of the first color light-emitting unit. With the cross voltage of the display panel remaining constant, the current corresponding to the other two color light-emitting units is less than the current corresponding to the first color light-emitting unit. This reduces the common layer voltage corresponding to the other two color light-emitting units, and may even prevent the turn-on voltage at that position from being reached, thus preventing the other two light-emitting units from being turned on. This effectively prevents lateral leakage between adjacent color light-emitting units, solves problems such as color crosstalk and reduced contrast in the display panel, and improves the display effect of the display panel.

[0086] The present invention also provides a display device, which includes a display panel having any of the features described in the above embodiments.

[0087] The display panel can be a flexible organic light-emitting display panel or a non-flexible organic light-emitting display panel. The light emission mode of the organic light-emitting display panel can be top-emitting, bottom-emitting, or double-sided emitting. The type of display panel can be any of the following: Organic Light-Emitting Diode (OLED) display panel, In-Plane Switching (IPS) display panel, Twisted Nematic (TN) display panel, Vertical Alignment (VA) display panel, electronic paper, QLED (Quantum Dot Light Emitting Diodes) display panel, or micro LED (μLED) display panel; this invention does not specifically limit this. The light emission mode of the display panel can be top-emitting, bottom-emitting, or double-sided emitting.

[0088] The display device provided in this embodiment of the invention can be applied in smart wearable devices (such as smart bracelets and smartwatches), as well as in devices such as smartphones, tablets, and displays.

[0089] Figure 10 This diagram illustrates a flowchart of a method for fabricating a display panel according to an embodiment of the present invention. This method is used to fabricate the display panel described in any of the above embodiments. The display panel includes multiple light-emitting regions, each containing a first color light-emitting unit and other color light-emitting units. In this embodiment, the other color light-emitting units are exemplified by a second color light-emitting unit and a third color light-emitting unit. Figure 10 As shown, the method for manufacturing the display panel may include steps S101-S105:

[0090] S101, A first electrode is formed on one side of the substrate.

[0091] The substrate can be flexible, thus stretchable, foldable, bendable, or rollable, allowing the display panel to be stretchable, foldable, bendable, or rollable. The substrate can be formed from any suitable insulating material that is flexible. The substrate serves to block moisture and oxygen, prevent the diffusion of moisture or impurities through the substrate, and provide a flat surface on the upper surface of the substrate.

[0092] The first electrode is usually the anode.

[0093] S102. A hole injection layer is formed on the side of the first electrode away from the substrate. In the same light-emitting region, the minimum thickness of the hole injection layer of the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layer of the other two color light-emitting units.

[0094] Specifically, Figure 11 This diagram illustrates a flow chart of a method for preparing a hole injection layer according to an embodiment of the present invention. Figure 11 As shown, the method for forming a hole injection layer on the first electrode may include steps S102a-S102c:

[0095] S102a. Based on the size of the light-emitting area and the opening width W of the mask, a first distance H1 and a second distance H2 are set, wherein the first distance H1 is the minimum vertical distance from the surface of the display panel to be vaporized to the side of the mask close to the surface to be vaporized, and the second distance H2 is the vertical distance from the side of the mask close to the evaporation source to the evaporation source. The mask is set parallel to the evaporation source.

[0096] In the embodiments provided by this invention, the surface of the display panel to be vapor-deposited is the surface of the first electrode away from the substrate. The size of the light-emitting area, the morphology of the hole injection layer, and the opening width W of the mask, as well as the first distance H1 and the second distance H2, are related. Typically, the sum of the first distance H1 and the second distance H2 is a constant value.

[0097] Specifically, Figure 12(a) shows a relationship diagram of the morphology of an evaporation source, a mask, and a hole injection layer provided in an embodiment of the present invention; Figure 12(b) shows a relationship diagram of the morphology of another evaporation source, a mask, and a hole injection layer provided in an embodiment of the present invention. As can be seen from Figures 12(a) and 12(b), when the first distance H1 and the second distance H2 remain constant, the larger the opening width W of the mask, the larger the size of the light-emitting area, and the smoother the morphology of the hole injection layer; conversely, the smaller the opening width W of the mask, the smaller the size of the light-emitting area, and the steeper the morphology of the hole injection layer.

[0098] Figure 12(c) shows a relationship diagram of the morphology of an evaporation source, a mask, and a hole injection layer provided in another embodiment of the present invention. As can be seen from Figures 12(a) and 12(c), when the opening width W of the mask remains constant, the closer the mask is to the evaporation source (i.e., the larger the first distance H1 and the smaller the second distance H2), the larger the size of the light-emitting area and the smoother the morphology of the hole injection layer; the farther the mask is from the evaporation source (i.e., the smaller the first distance H1 and the larger the second distance H2), the smaller the size of the light-emitting area and the steeper the morphology of the hole injection layer.

[0099] Understandably, the gentler the morphology of the hole injection layer, the more uniform the film formed in the coverage area of ​​the light-emitting region; conversely, the steeper the morphology of the hole injection layer, the more reliable it is in preventing lateral leakage between adjacent color light-emitting units in the light-emitting region. Therefore, the first distance H1 and the second distance H2 can be designed according to actual needs (i.e., the size of the sub-display area and the opening width W of the mask).

[0100] Figure 13 This diagram illustrates the calculation of the hole injection layer thickness at position m according to an embodiment of the present invention. Figure 13 As shown, for any luminescent region, the thickness of the hole injection layer at position m can be calculated using the following formula:

[0101] Where m represents any position in the air injection layer; θ0 is the angle between the line connecting the midpoint of the evaporation source and the edge of the luminous region and the plane containing the evaporation source; θ m Let θ be the angle between the line connecting the midpoint of the evaporation source and position m and the plane containing the evaporation source; H(θ) is the function relating the evaporation rate of the evaporation source to the angle θ.

[0102] For example, the thickness at position 'a' at the outermost edge of the hole injection layer. Thickness at position b, center of hole injection layer

[0103] In one embodiment, the opening width W of the mask is greater than or equal to the effective pixel width of the first color light-emitting unit, and less than or equal to the sum of the effective pixel width of the first color light-emitting unit and the width of the pixel-defining layers located on both sides of the first color light-emitting unit.

[0104] When the first distance H1 and the second distance H2 remain unchanged, the larger the opening width W of the mask, the larger the size of the light-emitting area and the smoother the morphology of the hole injection layer; the smaller the opening width W of the mask, the smaller the size of the light-emitting area and the steeper the morphology of the hole injection layer.

[0105] In one embodiment, the width of the light-emitting region is It can be seen that the width of the light-emitting area is related to the opening width W of the mask, the first distance H1 and the second distance H2. When preparing the hole injection layer, the size of the light-emitting area can be reasonably controlled by adjusting the opening width W of the mask, the first distance H1 and the second distance H2.

[0106] Optionally, the thickness of the mask can be in the millimeter range.

[0107] S102b: Control the position of the mask plate according to the first distance H1 and the second distance H2.

[0108] The mask can move back and forth in a direction perpendicular to the plane of the display panel to control the position of the mask according to the first distance H1 and the second distance H2.

[0109] S102c: Turn on the evaporation source and deposit a hole injection layer on the side of the first electrode away from the substrate.

[0110] S103. A hole transport layer is formed on the side of the hole injection layer away from the first electrode.

[0111] In one embodiment, when forming the hole transport layer in step S103, the mask provided in step S102 can be used to form a hole transport layer with the same morphology as the hole injection layer. This can reduce the process complexity of the display panel and reduce the manufacturing cost.

[0112] S104. A light-emitting layer is formed on the side of the hole transport layer away from the hole injection layer.

[0113] S105. A second electrode is formed on the side of the light-emitting layer away from the hole transport layer.

[0114] The second electrode is usually the cathode. Holes injected from the anode and electrons injected from the cathode recombine in the luminescent layer to generate excitons, thereby causing the luminescent layer to emit light.

[0115] This invention provides a method for fabricating a display panel. By dividing the display panel into multiple light-emitting regions and designing the morphology of the hole injection layer for different color light-emitting units within the same light-emitting region, a hole injection layer is fabricated where the minimum thickness of the hole injection layer for the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layers for the other two color light-emitting units. Compared to the conventional method of using equal-thickness hole injection layers in display panels, in this invention, because the minimum thickness of the hole injection layer for the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layers for the other two color light-emitting units, the lateral resistance of the hole injection layers for the other two color light-emitting units is greater than that of the first color light-emitting unit. With the cross-voltage of the display panel remaining constant, the current corresponding to the other two color light-emitting units is less than the current corresponding to the first color light-emitting unit. This reduces the common layer voltage corresponding to the other two color light-emitting units, potentially preventing them from reaching the turn-on voltage and thus preventing the other two light-emitting units from being activated. This effectively prevents lateral leakage between adjacent color light-emitting units, solves problems such as color crosstalk and decreased contrast in the display panel, and improves the display effect.

[0116] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A display panel, characterized by, The display panel comprises a plurality of light-emitting areas, each of the light-emitting areas comprises a first color light-emitting unit and other color light-emitting units, each of the light-emitting units comprises a hole injection layer; In the same light-emitting area, the minimum thickness of the hole injection layer of the first color light-emitting unit is greater than or equal to the maximum thickness of the hole injection layer of the other color light-emitting units, and the thickness of the hole injection layer of the other color light-emitting units located at the periphery of the first color light-emitting unit gradually decreases from the center of the first color light-emitting unit to the edge, and the ratio of the maximum thickness of the hole injection layer at the center of the first color light-emitting unit to the minimum thickness of the hole injection layer at the edge of the other color light-emitting units is greater than or equal to 2.

2. The display panel of claim 1, wherein the thickness of the hole injection layer of the first color light-emitting unit is uniform; or the thickness of the hole injection layer of the first color light-emitting unit gradually decreases from the center of the first color light-emitting unit to the edge; or the hole injection layer of the first color light-emitting unit comprises a first area and a second area surrounding the first area, the thickness of the hole injection layer of the first color light-emitting unit in the first area is uniform, and the thickness of the hole injection layer of the first color light-emitting unit in the second area gradually decreases from the center of the first color light-emitting unit to the edge.

3. The display panel of claim 1 or 2, wherein each light-emitting unit further comprises a first electrode, a hole transport layer, a light-emitting layer and a second electrode which are stacked in the light-emitting direction of the display panel, and the hole injection layer is located between the first electrode and the hole transport layer; In the same light-emitting area, the thickness of the hole transport layer of the first color light-emitting unit is equal to the thickness of the hole transport layer of the other color light-emitting units; or, in the same light-emitting area, the minimum thickness of the hole transport layer of the first color light-emitting unit is greater than or equal to the maximum thickness of the hole transport layer of the other color light-emitting units.

4. The display panel of claim 3, wherein, The thickness of the hole transport layer of the first color light-emitting unit is uniform; or the thickness of the hole transport layer of the first color light-emitting unit gradually decreases from the center of the first color light-emitting unit to the edge; or the hole transport layer of the first color light-emitting unit comprises a third area and a fourth area surrounding the third area, the thickness of the hole transport layer of the first color light-emitting unit in the third area is uniform, and the thickness of the hole transport layer of the first color light-emitting unit in the fourth area gradually decreases from the center of the first color light-emitting unit to the edge.

5. The display panel of claim 3, wherein, In the same light-emitting area, the thickness of the hole transport layer of the other color light-emitting units located at the periphery of the first color light-emitting unit gradually decreases from the center of the first color light-emitting unit to the edge.

6. The display panel of claim 1 or 2, wherein, each of the light emitting regions comprises one first color light emitting unit, one second color light emitting unit and one third color light emitting unit; wherein, in a first direction and / or in a second direction, the first color light emitting unit is located between the second color light emitting unit and the third color light emitting unit; or, each of the light emitting regions comprises one first color light emitting unit, two second color light emitting units and two third color light emitting units; wherein, in a first direction, the first color light emitting unit is located between the two second color light emitting units; in a second direction, the first color light emitting unit is located between the two third color light emitting units; the first direction intersects the second direction.

7. The display panel of claim 6, wherein, the first color light emitting unit emits blue light, the second color light emitting unit emits green light, and the third color light emitting unit emits red light; or, the first color light emitting unit emits blue light, the second color light emitting unit emits red light, and the third color light emitting unit emits green light.

8. A display device, characterized by comprising: A display panel as claimed in any one of claims 1-7.

9. A method for manufacturing a display panel, characterized by, A method for manufacturing a display panel as claimed in any one of claims 1-7, the display panel comprising a plurality of light emitting regions, each of the light emitting regions comprising a first color light emitting unit and other color light emitting units, the method comprising: forming a first electrode, a hole injection layer, a hole transport layer, a light emitting layer and a second electrode on one side of a substrate, in the same light emitting region, the minimum thickness of the hole injection layer of the first color light emitting unit is greater than or equal to the maximum thickness of the hole injection layer of the other color light emitting units, and the thickness of the hole injection layer of the other color light emitting units located around the first color light emitting unit gradually decreases in a direction from the center of the first color light emitting unit to the edge, the ratio of the maximum thickness of the hole injection layer at the center of the first color light emitting unit to the minimum thickness of the hole injection layer at the edge of the other color light emitting units is greater than or equal to 2; wherein the method of forming the hole injection layer on the side of the first electrode away from the substrate comprises: according to the size of the light emitting region and the opening width W of the mask plate, setting a first distance H1 and a second distance H2, wherein the first distance H1 is the minimum vertical distance from the evaporation surface of the display panel to the side of the mask plate close to the evaporation surface, and the second distance H2 is the vertical distance from the side of the mask plate close to the evaporation source to the evaporation source; controlling the position of the mask plate according to the first distance H1 and the second distance H2; opening the evaporation source and evaporating the hole injection layer on the first electrode.

10. The method of manufacturing a display panel according to claim 9, wherein, For any of the light emitting regions, the hole injection layer has a thickness at position m of ; wherein m is any position of the hole injection layer; is the angle between the line connecting the midpoint of the evaporation source and the edge of the light emitting area and the plane in which the evaporation source lies; is the angle between the line connecting the midpoint of the evaporation source and the position m and the plane in which the evaporation source lies; is the relationship function of the evaporation rate of the evaporation source and the angle .

11. The method of manufacturing a display panel according to claim 10, wherein, The opening width W of the mask plate is greater than or equal to the effective pixel width of the first color light emitting unit and less than or equal to the sum of the effective pixel width of the first color light emitting unit and the width of the pixel defining layer located on both sides of the first color light emitting unit.

12. The method of manufacturing a display panel according to claim 11, wherein, The width of the light emitting region is .

Images