Patent Publication Number: US-10333093-B2

Title: OLED substrate and manufacture method thereof

Description:
FIELD OF THE INVENTION 
     The present invention relates to a display technology field, and more particularly to an OLED substrate and a manufacture method thereof. 
     BACKGROUND OF THE INVENTION 
     The Organic Light Emitting Diodes (OLED) display device possesses many outstanding properties of self-illumination, low driving voltage, high luminescence efficiency, short response time, high clarity and contrast, near 180° view angle, wide range of working temperature, applicability of flexible display and large scale full color display. The OLED is considered as the most potential display device. 
     The OLED can be categorized as Passive matrix OLED (PMOLED) and (Active matrix OLED) AMOLED according to their driving types. The AMOLED comprises pixels arranged in array and belongs to active display type, which has high lighting efficiency and is generally utilized for the large scale display devices of high resolution. 
       FIG. 1  is a structure diagram of an OLED display device according to prior art. As shown in  FIG. 1 , the OLED display device comprises: an OLED substrate  600  and a package cover plate  700  located on the OLED substrate  600 ; the OLED substrate  600  generally comprises: a substrate  100 , a plurality of anodes  200  separately located on the substrate  100 ; a pixel definition layer (PDL)  300  located on the substrate  100  and the plurality of anodes  200 , a plurality of spacers  500  located on the pixel definition layer  300 , a plurality of openings  310  being located on the pixel definition layer  300  and respectively corresponding to the plurality of anodes  200 , and a Hole Injection Layer  410 , a Hole Transporting Layer  420 , an organic light emitting layer  430 , an Electron Transport Layer  440 , an Electron Injection Layer  450  and a cathode  460  which are sequentially stacked up from bottom to top in the plurality of openings  310  and on the cathodes  200 ; the package cover plate  700  contacts the plurality of spacers  500  on the OLED substrate  600 . 
     Specifically, the cathodes  200 , the Hole Injection Layer  410 , the Hole Transporting Layer  420 , the organic light emitting layer  430 , the Electron Transport Layer  440 , the Electron Injection Layer  450  and the cathode  460  which are sequentially stacked up from bottom to top construct an OLED element, together. The OLED element generally uses ITO and metal to respectively be the anode  200  and the cathode  460  of the element. Under the driving of a certain voltage, the electrons and the holes are respectively injected into the Electron Transport Layer  440  and the Hole Transporting Layer  420  from the cathode  460  and the anode  200 . The electrons and the holes migrate from the Electron Transport Layer  440  and Hole Transporting Layer  420  to the organic light emitting layer  430  and bump into each other in the organic light emitting layer  430  to form excitons to excite the emitting molecules. The latters can illuminate after the radiative relaxation. 
     Specifically, in the production process of the OLED substrate  600 , the manufacture process of the substrate  100 , the anodes  200  and the pixel definition layer  300  is generally named to be the TFT manufacture process. The following manufacture process of the Hole Injection Layer  410 , the Hole Transporting Layer  420 , the organic light emitting layer  430 , the Electron Transport Layer  440 , the Electron Injection Layer  450  and the cathode  460  is named to be the OLED manufacture process. Because the substrate size of the OLED manufacture process is generally smaller than the substrate size of the TFT manufacture process, it is necessary to cut the accomplished substrate of the TFT manufacture process (the carrier is generally the glass) before the OLED manufacture process. The knife flywheel is used for cutting in general, and because the glass debris generated by the cutting will cause the damage to the OLED element, a photoresist (PR) layer  800  (as shown in  FIG. 2 ) is generally coated on the surface of the accomplished substrate of the TFT manufacture process before cutting. After cutting, the photoresist layer  800  is stripped. Because the photoresist material, i.e. the same material of the photoresist layer  800 , is also commonly used for manufacture the pixel definition layer  300 , is can be easy to cause the wrong stripping of the pixel definition layer  300  in the stripping process of the photoresist layer  800 , and after the following film structure of the Hole Injection Layer  410 , the Hole Transporting Layer  420 , the organic light emitting layer  430 , the Electron Transport Layer  440 , the Electron Injection Layer  450  and the cathode  460  is formed, it will lead to the loss of the pixel definition layer  300  for protecting the plurality of anodes  200  and the short circuit among them, and thus lead to the failure of the OLED element. 
     Meanwhile, as shown in  FIG. 3 , in the OLED manufacture process, the evaporation processes for the structure layers of the Hole Injection Layer  410 , the Hole Transporting Layer  420 , the organic light emitting layer  430 , the Electron Transport Layer  440 , the Electron Injection Layer  450  and the cathode  460  need to use the FMM (Fine Metal Mask)  900 . Because the stability of the photoresist material used for the pixel definition layer  300  is not strong, and is extremely volatilized onto the fine metal mask  900  to cause the pollution of the fine metal mask  900 . Accordingly, the clean frequency of the fine metal mask  900  is increased, and the usage efficiency is decreased to raise the production cost. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to provide a manufacture method of an OLED substrate of the present invention, which can reduce the risk that pixel definition layer is wrong stripped in the photoresist stripping process, and meanwhile, reduce the risk that the fine metal mask is polluted in the evaporation process. 
     Another objective of the present invention is to provide an OLED substrate, which is manufactured by the aforesaid manufacture method of the OLED substrate. The structure of the pixel definition layer is complete, and can effectively protect the anodes and the substrate thereunder, and the element performance is good. 
     For realizing the aforesaid objectives, the present invention provides a manufacture method of an OLED substrate, comprising steps of: 
     step  1 , providing a substrate, and forming a plurality of anodes which are separately located on the substrate; depositing an inorganic film layer on the substrate and the plurality of anodes; 
     step  2 , employing a half tone mask to implement a patterning treatment to the inorganic film layer to obtain a pixel definition layer, a plurality of spacers located on the pixel definition layer, and a plurality of openings being located on the pixel definition layer and respectively corresponding to the plurality of anodes, and each opening exposes at least a portion of the corresponding anode to manufacture a first substrate; 
     step  3 , coating a photoresist layer on the first substrate, and the photoresist layer covering the pixel definition layer, the plurality of spacers and anodes; 
     cutting the first substrate coated with the photoresist layer to obtain a plurality of second substrates; 
     step  4 , stripping the photoresist layer on the second substrate to obtain a third substrate; 
     step  5 , sequentially forming a Hole Injection Layer, a Hole Transporting Layer, an organic light emitting layer, an Electron Transport Layer, an Electron Injection Layer and a cathode from bottom to top in the plurality of openings on the third substrate to manufacture the OLED substrate. 
     The substrate is a TFT substrate. 
     A material of the inorganic film layer comprises at least one of silicon nitride and silicon oxide. 
     A material of the anode is transparent conductive metal oxide, and a material of the cathode is metal. 
     In step  3 , a knife flywheel is employed to cut the first substrate coated with the photoresist layer; 
     in step  4 , photoresist stripper is employed to strip the photoresist layer on the second substrate; 
     in step  5 , a fine metal mask is employed with an evaporation method to sequentially form the Hole Injection Layer, the Hole Transporting Layer, the organic light emitting layer, the Electron Transport Layer, the Electron Injection Layer and the cathode from bottom to top in the plurality of openings on the third substrate. 
     The present invention further provides an OLED substrate, comprising a substrate, a plurality of anodes separately located on the substrate; a pixel definition layer located on the substrate and the plurality of anodes, a plurality of spacers located on the pixel definition layer, a plurality of openings being located on the pixel definition layer and respectively corresponding to the plurality of anodes, and a Hole Injection Layer, a Hole Transporting Layer, an organic light emitting layer, an Electron Transport Layer, an Electron Injection Layer and a cathode which are sequentially stacked up from bottom to top in the plurality of openings and on the cathodes; wherein both materials of the pixel definition layer and the plurality of spacers are inorganic materials. 
     The substrate is a TFT substrate. 
     The inorganic material comprises at least one of silicon nitride and silicon oxide. 
     A material of the anode is transparent conductive metal oxide, and a material of the cathode is metal. 
     The present invention further provides a manufacture method of an OLED substrate, comprising steps of: 
     step  1 , providing a substrate, and forming a plurality of anodes which are separately located on the substrate; depositing an inorganic film layer on the substrate and the plurality of anodes; 
     step  2 , employing a half tone mask to implement a patterning treatment to the inorganic film layer to obtain a pixel definition layer, a plurality of spacers located on the pixel definition layer, and a plurality of openings being located on the pixel definition layer and respectively corresponding to the plurality of anodes, and each opening exposes at least a portion of the corresponding anode to manufacture a first substrate; 
     step  3 , coating a photoresist layer on the first substrate, and the photoresist layer covering the pixel definition layer, the plurality of spacers and anodes; 
     cutting the first substrate coated with the photoresist layer to obtain a plurality of second substrates; 
     step  4 , stripping the photoresist layer on the second substrate to obtain a third substrate; 
     step  5 , sequentially forming a Hole Injection Layer, a Hole Transporting Layer, an organic light emitting layer, an Electron Transport Layer, an Electron Injection Layer and a cathode from bottom to top in the plurality of openings on the third substrate to manufacture the OLED substrate; 
     wherein the substrate is a TFT substrate; 
     wherein a material of the inorganic film layer comprises at least one of silicon nitride and silicon oxide. 
     The benefits of the present invention are: the present invention provides a manufacture method of an OLED substrate, and by utilizing the inorganic material to manufacture the pixel definition layer, it can reduce the risk that pixel definition layer is wrong stripped in the photoresist stripping process, and meanwhile, reduce the risk that the fine metal mask is polluted in the evaporation process, and thus to decrease the clean frequency of the fine metal mask and to raise the usage efficiency of the fine metal mask. The present invention provides an OLED substrate, which is manufactured by the aforesaid manufacture method of the OLED substrate. The structure of the pixel definition layer is complete, and can effectively protect the anodes and the substrate thereunder, and the element performance is good. 
     In order to better understand the characteristics and technical aspect of the invention, please refer to the following detailed description of the present invention is concerned with the diagrams, however, provide reference to the accompanying drawings and description only and is not intended to be limiting of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For better explaining the technical solution and the effect of the present invention, the present invention will be further described in detail with the accompanying drawings and the specific embodiments. 
       In drawings, 
         FIG. 1  is a structure diagram of an OLED display device according to prior art; 
         FIG. 2  is a photoresist coating diagram of an OLED substrate in the OLED display device according to prior art before the OLED process; 
         FIG. 3  is an evaporation process diagram of an OLED substrate in the OLED display device according to prior art; 
         FIG. 4  is a flowchart of a manufacture method of an OLED substrate according to the present invention; 
         FIGS. 5-6  are diagrams of step  1  of a manufacture method of an OLED substrate according to the present invention; 
         FIG. 7  is a diagram of step  2  of a manufacture method of an OLED substrate according to the present invention; 
         FIGS. 8-9  are diagrams of step  3  of a manufacture method of an OLED substrate according to the present invention; 
         FIG. 10  is a diagram of step  4  of a manufacture method of an OLED substrate according to the present invention; 
         FIGS. 11-12  are diagrams of step  5  of a manufacture method of an OLED substrate according to the present invention and  FIG. 12  is a structure diagram of the OLED substrate of the present invention; 
         FIG. 13  is a diagram of step  20  of a manufacture method of an OLED display device according to the present invention and also a structure diagram of the OLED display device of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     For better explaining the technical solution and the effect of the present invention, the present invention will be further described in detail with the specific embodiments. 
     Please refer to  FIG. 4 . The present invention first provides a manufacture method of an OLED substrate, comprising steps of: 
     step  1 , as shown in  FIG. 5 , providing a substrate  10 , and forming a plurality of anodes  20  which are separately located on the substrate  10 ; 
     as shown in  FIG. 6 , depositing an inorganic film layer  80  on the substrate  10  and the plurality of anodes  20 ; 
     Preferably, the substrate  10  is a TFT substrate. The OLED substrate manufactured in the following is applied in an AMOLED display device. 
     Specifically, a material of the inorganic film layer  80  comprises at least one of silicon nitride (SiNx) and silicon oxide (SiOx). 
     Specifically, a material of the anode  20  is transparent conductive metal oxide. Preferably, the material of the anode  20  is Indium Tin Oxide (ITO). 
     step  2 , as shown in  FIG. 7 , employing a half tone mask  85  to implement a patterning treatment to the inorganic film layer  80  to obtain a pixel definition layer  30 , a plurality of spacers  50  located on the pixel definition layer  30 , and a plurality of openings  31  being located on the pixel definition layer  30  and respectively corresponding to the plurality of anodes  20 , and each opening  31  exposes at least a portion of the corresponding anode  20  to manufacture a first substrate  91 . 
     Specifically, heights of the plurality of spacers  50  are the same; preferably, all the shapes of the plurality of spacers  50  are columnar. 
     step  3 , as shown in  FIG. 8 , coating a photoresist layer  95  on the first substrate  91 , and the photoresist layer  95  covering the pixel definition layer  30 , the plurality of spacers  50  and anodes  20 ; 
     as shown in  FIG. 9 , cutting the first substrate  91  coated with the photoresist layer  95  to obtain a plurality of second substrates  92 . 
     Specifically, in step  3 , a knife flywheel is employed to cut the first substrate  91  coated with the photoresist layer  95 . 
     step  4 , as shown in  FIG. 10 , stripping the photoresist layer  95  on the second substrate  92  to obtain a third substrate  93 . 
     Specifically, in step  4 , photoresist stripper is employed to strip the photoresist layer  95  on the second substrate  92 . In the phtoresist stripping process, because the material of the pixel definition layer  30  is inorganic material, the photoresist stripper will not damage the pixel definition layer  30 , and the pixel definition layer  30  can effectively protect the anodes  20  and the substrate  10  thereunder. 
     step  5 , as shown in  FIGS. 11-12 , sequentially forming a Hole Injection Layer  41 , a Hole Transporting Layer  42 , an organic light emitting layer  43 , an Electron Transport Layer  44 , an Electron Injection Layer  45  and a cathode  46  from bottom to top in the plurality of openings  31  on the third substrate  93  to manufacture the OLED substrate  60 . 
     Specifically, in step  5 , a fine metal mask  65  is employed with an evaporation method to sequentially form the Hole Injection Layer  41 , the Hole Transporting Layer  42 , the organic light emitting layer  43 , the Electron Transport Layer  44 , the Electron Injection Layer  45  and the cathode  46  from bottom to top in the plurality of openings  31  on the third substrate  93 . 
     Because the material of the pixel definition layer  30  is inorganic material, and the quality is more stable, and thus will not be volatilized to the fine metal mask  65  to lead to the pollution of the fine metal mask  65 , and thus to decrease the clean frequency of the fine metal mask  65  and to raise the usage efficiency of the fine metal mask  65 . 
     Specifically, a material of the cathode  46  is metal, and preferably, the material of the cathode  46  comprises at least one of magnesium, silver and aluminum. 
     In the aforesaid manufacture method of the OLED substrate, by utilizing the inorganic material to manufacture the pixel definition layer  30 , it can reduce the risk that pixel definition layer  30  is wrong stripped in the photoresist stripping process, and meanwhile, to reduce the risk that the fine metal mask  65  is polluted in the evaporation process, and thus to decrease the clean frequency of the fine metal mask  65  and to raise the usage efficiency of the fine metal mask  65 . 
     On the basis of the aforesaid manufacture method of the OLED substrate, the present invention further provides a manufacture method of an OLED display device, comprising steps of: 
     step  10 , as shown in  FIGS. 5-12 , manufacturing an OLED substrate  60  with the aforesaid manufactured method of the OLED substrate; 
     step  20 , as shown in  FIG. 13 , providing a package cover plate  70 , and para combining and tight fitting the package cover plate  70  and the OLED substrate  60 , and the package cover plate  70  contacting the plurality of spacers  50  on the OLED substrate  60  to manufacture an OLED display device. 
     Specifically, a material of the package cover plate  70  is glass. 
     Specifically, in the OLED display device, the spacers  50  act to support the package cover plate  70 . 
     In the aforesaid manufacture method of the OLED display device, by utilizing the manufacture method of the OLED substrate to manufacture the OLED substrate  60 , it can reduce the risk that pixel definition layer  30  is wrong stripped in the photoresist stripping process, and meanwhile, to reduce the risk that the fine metal mask  65  is polluted in the evaporation process, and thus to decrease the clean frequency of the fine metal mask  65  and to raise the usage efficiency of the fine metal mask  65 . 
     Please refer to  FIG. 12 . On the basis of the aforesaid manufacture method of the OLED substrate, the present invention further provides an OLED substrate  60 , comprising a substrate  10 , a plurality of anodes  20  separately located on the substrate  10 ; a pixel definition layer  30  located on the substrate  10  and the plurality of anodes  20 , a plurality of spacers  50  located on the pixel definition layer  30 , a plurality of openings  31  being located on the pixel definition layer  30  and respectively corresponding to the plurality of anodes  20 , and a Hole Injection Layer  41 , a Hole Transporting Layer  42 , an organic light emitting layer  43 , an Electron Transport Layer  44 , an Electron Injection Layer  45  and a cathode  46  which are sequentially stacked up from bottom to top in the plurality of openings  31  and on the cathodes  20 ; wherein both materials of the pixel definition layer  30  and the plurality of spacers  50  are inorganic materials. 
     Preferably, the substrate  10  is a TFT substrate. The OLED substrate is applied in an AMOLED display device. 
     Specifically, the inorganic material comprises at least one of silicon nitride (SiNx) and silicon oxide (SiOx). 
     Specifically, a material of the anode  20  is transparent conductive metal oxide. Preferably, the material of the anode  20  is Indium Tin Oxide (ITO). 
     Specifically, a material of the cathode  46  is metal, and preferably, the material of the cathode  46  comprises at least one of magnesium, silver and aluminum. 
     Specifically, heights of the plurality of spacers  50  are the same; preferably, all the shapes of the plurality of spacers  50  are columnar. 
     In the foregoing OLED substrate, by utilizing the inorganic material to manufacture the pixel definition layer  30 , it can reduce the risk that pixel definition layer  30  is wrong stripped in the photoresist stripping process. The structure of the pixel definition layer  30  is complete, and can effectively protect the anodes  20  and the substrate  10  thereunder, and the element performance is good. 
     Please refer to  FIG. 13 . On the basis of the aforesaid manufacture method of the OLED device, the present invention further provides an OLED display device, comprising an OLED substrate  60  and a package cover plate  70  which are oppositely located and tight fitted; 
     The OLED substrate  60  is the foregoing OLED substrate  60 , and the package cover plate  70  contacts the plurality of spacers  50  on the OLED substrate  60 . 
     Specifically, a material of the package cover plate  70  is glass. 
     Specifically, in the OLED display device, the spacers  50  act to support the package cover plate  70 . 
     The aforesaid OLED display device comprises the aforesaid OLED substrate, and the element performance is good. 
     In conclusion, the present invention provides an OLED substrate and a manufacture method thereof. In the manufacture method of the OLED substrate of the present invention, by utilizing the inorganic material to manufacture the pixel definition layer, it can reduce the risk that pixel definition layer is wrong stripped in the photoresist stripping process, and meanwhile, reduce the risk that the fine metal mask is polluted in the evaporation process, and thus to decrease the clean frequency of the fine metal mask and to raise the usage efficiency of the fine metal mask. The OLED substrate of the present invention is manufactured by the aforesaid manufacture method of the OLED substrate. The structure of the pixel definition layer is complete, and can effectively protect the anodes and the substrate thereunder, and the element performance is good. 
     Above are only specific embodiments of the present invention, the scope of the present invention is not limited to this, and to any persons who are skilled in the art, change or replacement which is easily derived should be covered by the protected scope of the invention. Thus, the protected scope of the invention should go by the subject claims.