Display apparatus including an uneven structure, and method of manufacturing the same

1. A display apparatus, comprising:

a substrate;

a first electrode layer comprising a plurality of pixelated first electrodes and disposed on a surface of the substrate;

an organic multilayer comprising a first-type carrier auxiliary layer, a light-emitting layer and a second-type carrier auxiliary layer and disposed on a surface of the first electrode layer;

a second electrode layer disposed on a surface of the organic multilayer;

a plurality of OLED lighting elements arranged in a matrix on the substrate, each of the plurality of OLED lighting elements comprising a portion of the organic multilayer sandwiched by the pixelated first electrodes and the second electrode layer; and

a rough surface structure including randomly distributed humps and depressions disposed underneath the first-type carrier auxiliary layer between adjacent OLED lighting elements; wherein

in a direction away from the substrate, the first-type carrier auxiliary layer comprises a hole injection layer, a hole transport layer, and an electron blocking layer and the second-type carrier auxiliary layer comprises hole blocking layer, an electron transport layer, and an electron injection layer; or the first-type carrier auxiliary layer comprises a hole blocking layer, an electron transport layer, and an electron injection layer and the second-type carrier auxiliary layer comprises a hole injection layer, a hole transport layer, and an electron blocking layer,

a roughness of the rough surface structure is characterized by an average amplitude AR in a direction perpendicular to the substrate and an average cycle length GR in parallel to the substrate,

the average amplitude AR and an average cycle length GR satisfy 0.2D<AR<5D, and 0.2D<GR<10D; or satisfy AR>D and GR>AR, and

D denotes a total thickness of the first-type carrier auxiliary layer, the light-emitting layer, the second-type carrier auxiliary layer, and the second electrode layer.

2. The display apparatus of claim 1 , wherein a vertical projection of the rough surface structure on the substrate are in a mesh shape that each OLED light element is aligned with one opening of the mesh shaped rough surface structure.

3. The display apparatus of claim 1 , further comprising a pixel definition layer with an opening structure; wherein

the pixel definition layer is disposed between the first-type carrier auxiliary layer and the first electrode layer, and the opening structure exposes a portion of the first electrode; and

the rough surface structure is disposed between the pixel definition layer and the first-type carrier auxiliary layer.

4. The display apparatus of claim 3 , wherein a vertical projection of the rough surface structure is located within a vertical projection of the pixel definition layer on the substrate.

5. The display apparatus of claim 1 , wherein

the rough surface structure is made of a conductive material; and

the rough surface structure floats or is electrically connected to a potential input terminal.

6. The display apparatus of claim 1 , wherein the rough surface structure is made of an insulating material.

7. A preparation method of a display apparatus, comprising steps in process sequence:

providing a substrate;

forming a first electrode layer on the substrate; wherein the first electrode layer comprises a plurality of pixelated first electrodes;

forming a rough surface structure including randomly distributed humps and depressions;

forming a first-type carrier auxiliary layer on the pixelated first electrodes and the rough surface structure;

forming a light-emitting layer on the first-type carrier auxiliary layer;

forming a second-type carrier auxiliary layer on the light-emitting layer; and

forming a second electrode layer on the second-type carrier auxiliary layer; wherein

in a direction away from the substrate, the first-type carrier auxiliary layer comprises a hole injection layer, a hold transport layer, and an electron blocking layer and the second-type carrier auxiliary layer comprises a hole blocking layer, an electron transport layer, and an electron injection layer; or the first-type carrier auxiliary layer comprises a hole blocking layer, an electron transport layer, and an electron injection layer and the second-type carrier auxiliary layer comprises a hole injection layer, an hole transport layer, and an electron blocking layer,

a roughness of the rough surface structure is characterized by an average amplitude AR in a direction perpendicular to the substrate and an average cycle length GR in parallel to the substrate, wherein the average amplitude AR and an average cycle length GR satisfy 0.2D<AR<5D, and 0.2D<GR<10D; or satisfy AR>D, and GR>AR, and

D denotes a total thickness of the first-type carrier auxiliary layer, the light-emitting layer, the second-type carrier auxiliary layer, and the second layer.

8. The method of claim 7 , wherein forming the rough surface structure comprises:

forming the rough surface structure through a vapor deposition process during which an inert gas is introduced.

9. The method of claim 7 , wherein forming the rough surface structure comprises:

forming a pixel definition layer; and

forming the rough surface structure on the pixel definition layer; and

forming a plurality of opening structures on the pixel definition layer; wherein each of the plurality of opening structures exposes at least a portion of the first electrode.

10. The method of claim 7 , before forming the rough surface structure, further comprising:

forming a pixel definition layer; wherein forming the rough surface structure comprises:

forming the rough surface structure on the pixel definition layer; wherein

the rough surface structure is formed by using a wet etching process and/or a dry etching process; and

a plurality of opening structures is formed; each of the plurality of opening structures exposes at least a portion of the first electrode.