Pixel unit

Abstract

The utility model discloses a pixel unit, relates to display equipment technical field, the pixel unit includes substrate, three sub-pixel layer, anode layer and cathode layer, three sub-pixel layer along the direction far away from substrate stack up on the obverse side of substrate in proper order, the anode layer is provided on the obverse side of substrate, the obverse side of each sub-pixel layer is provided with one cathode layer, the cathode layer is provided on the obverse side of each sub-pixel layer, the cathode layer is provided on the obverse side of each sub-pixel layer. And the cathode layer is made of a transparent material. According to the utility model, the three sub-pixel layers with three primary colors are overlapped, which is equivalent to that the area occupied by each of the three sub-pixel layers is increased to three times of the original area, the area occupied by each sub-pixel layer is increased, the aperture ratio is further increased, and the display effect is improved; according to the utility model, the cut-off structure is arranged to manufacture the three sub-pixel layers and the cathode layer by utilizing an evaporation process, and a precise mask plate or organic photoetching is not needed, so that the manufacturing cost of the pixel unit is reduced, and the process steps are simplified.

Description

Technical Field

[0001] The utility model relates to the technical field of display devices, in particular to a pixel unit. Background Art

[0002] Real RGB pixels are a display technology that can directly display the true color of each pixel. This technology can provide more accurate and rich color expressiveness, significantly improving the quality of images;

[0003] However, the OLED color blocks of the three colors in the existing Real RGB pixels are usually arranged side by side, resulting in a low aperture ratio, which in turn affects the display effect of the display.

[0004] Based on this, there is an urgent need for a new solution to at least solve some of the above problems Summary of the Utility Model

[0005] The purpose of the utility model is to provide a pixel unit to solve the problems existing in the above-mentioned prior art and improve the display effect of the display.

[0006] To achieve the above purpose, the utility model provides the following solution:

[0007] The utility model provides a pixel unit, which includes a substrate, three sub-pixel layers, an anode layer and a cathode layer. The three sub-pixel layers are sequentially stacked on the front of the substrate along the direction away from the substrate. The anode layer is arranged on the front of the substrate. A cathode layer is arranged on the front of each sub-pixel layer, and the cathode layer is made of a transparent material.

[0008] Preferably, an isolation sleeve is arranged on the front of the substrate. The three stacked sub-pixel layers are located inside the isolation sleeve. A cutting structure is arranged on the side of the isolation sleeve away from the substrate. The cutting structure is annular. One end of the cutting structure is connected to the isolation sleeve, and the other end extends towards the middle of the isolation sleeve to form a window.

[0009] Preferably, a through hole penetrating the back and front of the substrate is arranged on the substrate. A pixel circuit is arranged on the back of the substrate. The anode layer and the cathode layer are connected through the through hole and the pixel circuit.

[0010] Preferably, the three cathode layers respectively extend from the three side parts of the sub-pixel layer to the substrate and cover the through holes on the substrate.

[0011] The utility model has obtained the following technical effects compared with the prior art:

[0012] First, in the present utility model, the three sub-pixel layers of the three primary colors are overlapped, which is equivalent to increasing the area occupied by each sub-pixel layer to 3 times the original, increasing the area occupied by each sub-pixel layer, thereby increasing the aperture ratio and improving the display effect.

[0013] Second, the present utility model sets a cutting structure to fabricate the three sub-pixel layers and the cathode layer by using an evaporation process, without the need for a precision mask or organic lithography, reducing the cost of fabricating pixel units and simplifying the process steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 It is a cross-sectional schematic diagram of a pixel unit provided by an embodiment of the present utility model;

[0016] Figure 2 It is a flowchart of a method for fabricating a pixel unit provided by an embodiment of the present utility model;

[0017] Figure 3 It is an equivalent circuit diagram of a pixel unit provided by an embodiment of the present utility model;

[0018] Figure 4 For a pixel unit provided by an embodiment of the present utility model using Figure 3 the equivalent circuit described above, it is a relationship diagram of voltage / current and emission color. Different colors can be emitted from the pixel unit by controlling the voltage / current according to this relationship diagram;

[0019] Figure 5 It is a simulation diagram of the actual situation of a pixel unit provided by an embodiment of the present utility model;

[0020] Figure 6 It is a simulation diagram of the actual situation of a pixel unit provided by another embodiment of the present utility model;

[0021] In the figure: 1 - sub-pixel layer; 2 - cathode layer; 3 - substrate; 4 - anode layer; 5 - through hole; 6 - cutting structure; 7 - isolation sleeve; 8 - linear evaporation source. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The present invention provides a pixel unit, as Figure 1 shown, which includes a substrate 3, three sub-pixel layers 1, an anode layer 4, and a cathode layer 2. The three sub-pixel layers 1 are sequentially stacked on the front of the substrate 3 along the direction away from the substrate 3. The anode layer 4 is disposed on the front of the substrate 3, and a cathode layer 2 is disposed on the front of each sub-pixel layer 1. The cathode layer 2 is made of a transparent material.

[0025] Among them, the three sub-pixel layers 1 are respectively an OLED organic layer that emits blue light, an OLED organic layer that emits red light, and an OLED organic layer that emits green light.

[0026] In the embodiment of the present invention, by overlapping the three sub-pixel layers 1 of the three primary colors, it is equivalent to increasing the area occupied by each of the three sub-pixel layers 1 to 3 times the original, increasing the area occupied by each sub-pixel layer 1, thereby increasing the aperture ratio and improving the display effect.

[0027] Note: In the present invention, the two middle cathode layers can also be referred to as common cathode-anode layers because these two cathode layers 2 serve as the cathodes of the sub-pixel layers below them and at the same time serve as the anodes of the sub-pixel layers above them.

[0028] Below the substrate 3, that is, on the back surface, there is a control circuit, which controls the voltage and current of the cathode layer 2 and the anode layer 4 separately, so that each sub-pixel layer 1 can emit light independently.

[0029] The specific voltage control method is as Figure 3 and Figure 4 shown.

[0030] In some embodiments, an isolation sleeve 7 is provided on the front surface of the substrate 3. Three stacked sub-pixel layers 1 are located inside the isolation sleeve 7. A cutting structure 6 is provided on the side of the isolation sleeve 7 away from the substrate 3. The cutting structure 6 is annular. One end of the cutting structure 6 is connected to the isolation sleeve 7, and the other end extends towards the middle of the isolation sleeve 7 to form a window. The three sub-pixel layers 1 are preferably fabricated by an evaporation process. The cathode layer 2 can be fabricated by an evaporation process or a sputtering process. The annular edge inside the cutting structure 6 is used to cut off the evaporated or sputtered material, so that the material is only evaporated or sputtered on the target area of the substrate 3 inside the isolation sleeve 7. RealRGB can be fabricated without a precision mask or organic lithography, reducing the cost of fabricating pixel units and simplifying the process steps.

[0031] Among them, the material of the isolation sleeve 7 is Si3N4, and the material of the cutting structure 6 is SiO2.

[0032] Note: The size of the window is determined according to the process conditions required. The process conditions include the size of the evaporation source, the distance between the evaporation source and the window, etc., so that the material on the substrate 3 after evaporation is exactly located within the target area, and other materials are located on the front surface of the cutting structure 6. This achieves the purpose of using the cutting structure 6 to cut off the evaporated material.

[0033] In some embodiments, through holes 5 penetrating the back surface and the front surface are provided on the substrate 3. A pixel circuit is provided on the back surface of the substrate 3. The anode layer 4 and the cathode layer 2 are connected through the through holes 5 and the pixel circuit.

[0034] In some embodiments, the three cathode layers 2 respectively extend from the three side portions of the sub-pixel layer 1 to the substrate 3 and cover the through holes 5 on the substrate 3.

[0035] In this embodiment, the three through holes 5 are respectively provided on the substrate 3 at the three side portions of the sub-pixel layer 1. One cathode layer 2 covers one through hole 5. A conductive structure is provided in the through hole 5 to realize the conduction between the cathode layer 2 and the pixel circuit.

[0036] The embodiment of the present invention also provides a method for fabricating a pixel unit, as Figures 1 to 2 shown, including:

[0037] Step 1: Fabricate 4 through holes 5 and the back surface pixel circuit on the substrate 3;

[0038] Step 2: Fabricate the anode layer 4 on the substrate 3;

[0039] Step 3: Sequentially fabricate the first sub-pixel layer, the first cathode layer, the second sub-pixel layer, the second cathode layer, the third sub-pixel layer and the third cathode layer on the substrate 3. Among them, the anode layer 4, the first cathode layer, the second cathode layer and the third cathode layer are respectively connected through the four through holes 5 and the pixel circuit on the back surface of the substrate 3.

[0040] The manufacturing method provided in this embodiment is used to manufacture the pixel units in the above several embodiments.

[0041] In some embodiments, step two further includes: manufacturing an isolation sleeve 7 and a cutting structure 6 on the front side of the substrate 3. A cutting structure 6 is provided on the side of the isolation sleeve 7 away from the substrate 3. The cutting structure 6 is annular. One end of the cutting structure 6 is connected to the isolation sleeve 7, and the other end extends towards the middle of the isolation sleeve 7 and forms a window.

[0042] Use the anodic process to sequentially manufacture an anode layer, a SiO2 layer, and a Si3N4 layer on the substrate, and then use the etching process to etch the SiO2 layer and the Si3N4 layer to form the isolation sleeve and the cutting structure.

[0043] Specifically, step three includes:

[0044] Adopt the evaporation process to sequentially evaporate a first sub-pixel layer, a first cathode layer, a second sub-pixel layer, a second cathode layer, a third sub-pixel layer, and a third cathode layer on the substrate 3.

[0045] Among them, the first cathode layer, the second cathode layer, and the third cathode layer can also be manufactured by the sputtering process.

[0046] When evaporating the first sub-pixel layer, the second sub-pixel layer, and the third sub-pixel layer, use a linear evaporation source 8 with a vertical nozzle for evaporation;

[0047] When evaporating the first cathode layer, the second cathode layer, and the third cathode layer, use a linear evaporation source 8 with an inclined nozzle for evaporation to form the first cathode layer, the second cathode layer, and the third cathode layer on the front side of the substrate 3.

[0048] More specifically, in order to facilitate the three cathode layers 2 to extend from the three side parts of the sub-pixel layer 1 to the substrate 3 respectively and cover the through holes 5 on the substrate 3, after evaporating the first cathode layer (forming the first cathode layer on the front side and the first side of the first sub-pixel layer), rotate the substrate 3 or the evaporation source 90 degrees or 180 degrees to facilitate forming the second cathode layer on the front side and the second side of the second sub-pixel layer. Similarly, before evaporating the third cathode layer, it is necessary to rotate again to facilitate forming the third cathode layer on the third side. Specific embodiment one:

[0050] As Figure 5 shown, Anode material: Al / TiN

[0051] First OLED organic layer: blue light;

[0052] Second OLED organic layer: green light;

[0053] Third OLED organic layer: red light;

[0054] The transparent cathode layer is Mg:Ag (9:1) with a thickness of 10 nm. Specific Embodiment 2:

[0056] As Figure 6 shown, the anode material: Al / TiN / ITO

[0057] The first OLED organic layer: red light;

[0058] The second OLED organic layer: green light;

[0059] The third OLED organic layer: blue light;

[0060] The transparent cathode layer is IZO (the method is angle sputtering, controlled by tilting the substrate), with a thickness of 30 nm.

[0061] Note: Along the direction away from the substrate are the first OLED organic layer, the second OLED organic layer, and the third OLED organic layer in sequence.

[0062] Figure 3 This is the equivalent circuit diagram of the pixel unit provided by the embodiment of the present invention.

[0063] Figure 4 This is the relationship diagram of voltage / current and emission color when the pixel unit provided by the embodiment of the present invention adopts Figure 3 the equivalent circuit described therein. The voltage / current can be controlled according to this relationship diagram so that the pixel unit emits different colors.

[0064] Figure 4 In

[0065] Specific examples are applied in the present invention to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A pixel unit, comprising a substrate, three sub-pixel layers, an anode layer and a cathode layer, characterized in that: The three sub-pixel layers are stacked in sequence on the front side of the substrate in a direction away from the substrate. The anode layer is arranged on the front side of the substrate. A cathode layer is arranged on the front side of each sub-pixel layer. The cathode layer is made of a transparent material.

2. The pixel unit according to claim 1, characterized in that: An isolation sleeve is provided on the front side of the substrate, and the three stacked sub-pixel layers are located in the isolation sleeve. A cutting structure is provided on the side of the isolation sleeve away from the substrate. The cutting structure is annular, and one end of the cutting structure is connected to the isolation sleeve, and the other end extends toward the middle of the isolation sleeve to form a window.

3. The pixel unit according to claim 1, characterized in that: The substrate is provided with a through hole penetrating the back side and the front side, a pixel circuit is provided on the back side of the substrate, and the anode layer and the cathode layer are connected with the pixel circuit through the through hole.

4. The pixel unit according to claim 3, characterized in that: The three cathode layers extend from three sides of the sub-pixel layer to the substrate respectively and cover the through holes on the substrate.

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