Patent Publication Number: US-2023165049-A1

Title: Method of manufacturing high-resolution micro-oled and display module

Description:
CROSS-REFERENCE TO RELATED INVENTIONS 
     This invention is an application which claims the priority of CN application Serial No. 201911105293.9, filed on Nov. 13, 2019, and titled as “method of manufacturing high-resolution Micro-OLED and display module”, the disclosures of which are hereby incorporated by reference in their entirety. 
     BACKGROUND 
     1. Technical Field 
     The invention relates to the field of manufacturing of the OLED (Organic Light-Emitting Diode) display, in particular to a method for manufacturing a high-resolution Micro-OLED and a display module with the high-resolution Micro-OLED. 
     2. Description of Related Art 
     Compared with CTR (Cathode Ray Tube) displays and TFT-LCD (Thin Film Transistor-Liquid Crystal Displays), the OLED displays have lighter and thinner design, wider viewing angle, faster response speed and lower power consumption, so that OLED displays have gradually attracted people&#39;s attention as the next generation of display devices. 
     The display methods for realizing full-color OLED include: RGB three-color arrangement light emitting method, blue light and light conversion layer method. Blue light and light conversion layer methods are widely used because of their low cost and simple process. However, the light conversion layer in the prior arts cannot completely absorb all the blue excitation light sources, so that each red/green sub-pixel emits red/green light accompanied by a certain proportion of blue light, which is thereby reducing the color gamut. 
     Hence, there is a need to provide a new method of manufacturing high-resolution Micro-OLED to solve the problems. 
     SUMMARY 
     The objective of the present invention is to provide a method for manufacturing a high-resolution Micro-OLED, which uses the localized surface plasmon resonance effect of the metal in the light conversion layer to make the intensity of the fluorescence peak the sub-pixel increases and the blue peak disappears, thereby effectively improving the overall color gamut. 
     In order achieve above-mentioned objectives, the present invention provides a method of manufacturing high-resolution Micro-OLED, the method comprises following steps: 
     S 1 : providing a base substrate and preparing a light-emitting pixel layer on the base substrate; 
     S 2 : preparing a thin film packaging layer on the light-emitting pixel layer to encapsulating the light-emitting pixel layer; 
     S 3 : preparing a black matrix layer and a light converting layer for converting one color into another color on the thin film packaging layer, and the light converting layer comprising color change layer; 
     S 4 : encapsulating the black matrix layer and the light converting layer to obtain high-resolution Micro-OLED. 
     As an improvement of the present invention, wherein the color layer comprises quantum dot layer, a nano metal layer and a barrier layer located between the quantum dot layer and the nano metal layer. 
     As an improvement of the present invention, wherein a method of preparing the color change layer comprises following steps: 
     S 31 : preparing the color change layer on the thin film packaging layer; 
     S 32 : pressing a transparent quartz imprint template on the thin film packaging layer by using nanoimprint technology, and applying a certain pressure; 
     S 33 : curing by using ultraviolet light; 
     S 34 : separating the quartz imprint template from the thin film packaging layer. 
     As an improvement of the present invention, wherein the method of preparing the color change layer also comprises a step: 
     S 35 : cleaning the quantum dot residue left on the thin film packaging layer by using plasma cleaning technology. 
     As an improvement of the present invention, wherein the step S 4  also comprises following steps: 
     S 41 : preparing a protective layer on the black matrix layer and the light converting layer by using an atomic layer deposition technique; 
     S 42 : encapsulating the cover plate with a photosensitive adhesive on the protective layer. 
     As an improvement of the present invention, wherein the protective layer is aluminum oxide. 
     As an improvement of the present invention, wherein the step S 1  comprises following steps: 
     S 11 : providing a base substrate, and preparing a plurality of regularly arranged via holes on the base substrate; 
     S 12 : evaporating an anode layer on the base substrate by using a self-aligning process, the anode layer comprising anode units corresponding to the via holes one by one; 
     S 13 : evaporating the OLED light-emitting layer on surface of the anode layer; 
     S 14 : evaporating a cathode layer on surface of the OLED light-emitting layer to form the light-emitting pixel layer. 
     As an improvement of the present invention, wherein the OLED light-emitting layer is a blue organic electroluminescent device. 
     As an improvement of the present invention, wherein the OLED light-emitting layer comprises an organic light emitting layer, a hole injection layer and a hole transport layer located between the anode layer and the organic light emitting layer, and an electron injection layer and an electron transport layer located between the cathode layer and the organic light emitting layer. 
     In order achieve above-mentioned objective, the present invention also provides a display module, comprising high-resolution Micro-OLED layer and thin film transistor array electrically connected to the high-resolution Micro-OLED layer, and the high-resolution Micro-OLED layer is made by method of manufacturing high-resolution Micro-OLED as described above. 
     The beneficial effects of the present invention are: a method for manufacturing a high-resolution Micro-OLED of the present invention uses the localized surface plasmon resonance effect of the metal in the light conversion layer to make the intensity of the fluorescence peak the sub-pixel increases and the blue peak disappears, thereby effectively improving the overall color gamut. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic flow chart of manufacturing method of the high-resolution Micro-OLED of the present invention. 
         FIG.  2    is a schematic flow chart of step S 1  shown in  FIG.  1   . 
         FIG.  3    is a schematic diagram of the manufacturing process of the color change layer. 
         FIG.  4    is a schematic diagram of the structure of the display module of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
     Reference will now be made to the drawing figures to describe the embodiments of the present disclosure in detail. In the following description, the same drawing reference numerals are used for the same elements in different drawings. 
     Referring to  FIG.  1    and  FIG.  4   , a method of manufacturing a high-resolution Micro-OLED of the present invention includes the following steps: 
     S 1 : providing a base substrate  10 , and producing a light-emitting pixel layer  20  on the base substrate  10 . 
     S 2 : preparing a thin film packaging layer  30  on the light emitting pixel layer  20  by using thin film packaging technology, to encapsulate the light emitting pixel layer  20 . 
     S 3 : preparing a black matrix layer  40  and a light converting layer  50  for converting one color into another color on the thin film packaging layer  30 , and setting the black matrix layer  40  and the light converting layer  50  at intervals. 
     S 4 : Encapsulating the black matrix layer  40  and the light converting layer  50  with a cover  60  to obtain a high-resolution Micro-OLED. 
     Referring to  FIG.  2    and  FIG.  4   , the step S 1  also includes the following steps: 
     S 11 : providing a base substrate  10 , and preparing a plurality of regularly arranged via holes  11  on the base substrate  10 . 
     S 12 : evaporating an anode layer  21  on the base substrate  10  by using a self-aligning process, the anode layer  21  comprising a plurality of anode units  211 ; the anode units  211  corresponding to the via holes  11  one by one. 
     S 13 : evaporating the OLED light-emitting layer  22  on a surface of the anode layer  21 . 
     S 14 : evaporating a cathode layer  23  on surface of the OLED light-emitting layer  22  to form the light-emitting pixel layer  20 . 
     The base substrate  10  is a silicon substrate. The anode layer  21  is composed of a plurality of anode units  211  arranged in a pixel pattern, and the anode units  211  are indium tin oxide film (ITO). In the present embodiment, the width of the anode unit  211  is 5 microns. The OLED light emitting layer  22  includes an organic light emitting layer, a hole injection layer and a hole transport layer located between the anode layer  21  and the organic light emitting layer, and an electron injection layer and an electron transport layer located between the cathode layer  23  and the organic light emitting layer. 
     Further, the hole transport layer is located between the organic light emitting layer and the hole injection layer; the electron transport layer is located between the organic light emitting layer and the electron injection layer. The cathode layer  23  is a conductive thin film layer made of metal or metal oxide material. In this embodiment, the OLED light emitting layer  22  is a blue organic electroluminescent device. 
     The thin film packaging layer  30  may be an organic thin film, an inorganic thin film, or an inorganic thin film stacked on an organic thin film. The film packaging layer  30  is provided with a film alignment mark  31 . The film alignment mark  31  may be composed of some grid bars with a certain pitch, or may be an alignment mark composed of other forms. 
     Please refer to  FIG.  4   , the light converting layer  50  includes a first color change layer  51 , a second color change layer  52 , and cavities  53  arranged at intervals. The first color change layer  51  and the second color change layer  52  have the same structure, including a quantum dot layer  501 , a nano metal layer  502 , and a barrier layer  503  located between the quantum dot layer  501  and the nano metal layer  502 . No color change layer is provided in the hole  53  so that the blue light emitted by the OLED light-emitting layer  22  can pass directly. Since the first color change layer  51  and the second color change layer  52  contain metal nanomaterials, the local surface plasmon resonance effect of the metal can be used to enhance the red and green fluorescence peaks and reduce blue light. Consequently, the color gamut is effectively improved. 
     Referring to  FIG.  3   , a method of manufacturing the first color change layer  51  and the second color change layer  52  includes following steps: 
     S 31 : manufacturing color change layer on the thin film packaging layer  30 ; 
     S 32 : pressing a transparent quartz imprint template on the thin film packaging layer  30  by using nanoimprint technology, and applying a certain pressure; 
     S 33 : curing by using ultraviolet light; 
     S 34 : separating the quartz imprint template from the thin film packaging layer  30 ; 
     S 35 : cleaning the quantum dot residue left on the thin film packaging layer  30  by using plasma cleaning technology. 
     Furthermore, the step S 4  also includes following steps: 
     S 41 : preparing a protective layer  61  on the black matrix layer  40  and the light conversion layer  50  by using an atomic layer deposition technique. The protective layer  61  is aluminum oxide. 
     S 42 : encapsulating the cover plate  60  with a photosensitive adhesive  62  on the protective layer  61 . 
     The cover plate  60  can be a glass plate or a polyimide (PI) cover plate. The cover plate  60  is fixed on the protective layer  61  by photosensitive adhesive  62 . 
     The present invention also discloses a display module, including a high-resolution Micro-OLED layer and a thin film transistor array electrically connected to the high-resolution Micro-OLED layer. The high-resolution Micro-OLED layer is made by the manufacturing method of high-resolution Micro-OLED of the present invention. 
     Compared with the prior art, the method of manufacturing the high-resolution Micro-OLED of the present invention utilizes the localized surface plasmon resonance effect of the metal in the light conversion layer  50  to increase the intensity of the fluorescence peak in the sub-pixel, and make the blue peak disappeared, so that the overall color gamut is effectively improved. 
     It is to be understood, however, that even though numerous characteristics and advantages of preferred and exemplary embodiments have been set out in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only; and that changes may be made in detail within the principles of present disclosure to the full extent indicated by the broadest general meaning of the terms in which the appended claims are expressed.