Patent Publication Number: US-2016246084-A1

Title: Method of Manufacturing Flexible Display Device and Flexible Display Device

Description:
TECHNICAL FIELD 
     Embodiments of the present invention relate to a method of manufacturing a flexible display device and the flexible display device manufactured by the method. 
     BACKGROUND 
     Liquid crystal display (LCD) technologies have developed dramatically in a recent decade, with great improvement from display sizes to display quality. Because a flexible display itself has a special bendable feature, the flexible display may be applied in many special user experiences. In existing technologies, an adhesion-peeling method is generally applied to manufacture flexible display devices. 
     SUMMARY 
     According to embodiments of the present invention, a method for manufacturing flexible display devices is provided, comprising: forming a sacrifice layer on a base substrate; forming a flexible substrate on the sacrifice layer; forming components of the flexible display device on the flexible substrate; irradiating the sacrifice layer with laser to separate the base substrate from the flexible substrate; and coating a material used to make a protection layer on the flexible substrate by a melted extrusion method for multiple times and cooling the material to form the protection layer. 
     In an example, the material for the sacrifice layer is one of amorphous silicon (a-Si), silicon oxide, silicon nitride and indium tin oxide (ITO). 
     In an example, the step of irradiating the sacrifice layer with laser to separate the base substrate from the flexible substrate comprises: absorbing the components of the flexible display device and rotating the flexible display device by 180 degrees by using a vacuum absorption manipulator, and then irradiating the sacrifice layer with laser to separate the flexible substrate from the base substrate. 
     In an example, the base substrate is a glass substrate. 
     According to embodiments of the present invention, another method for manufacturing flexible display devices is also provided, comprising: forming a sacrifice layer on a base substrate; forming components of the flexible display device on the sacrifice layer; irradiating the sacrifice layer with laser to separate the base substrate from the components of the flexible display device; and coating a material used to make a protection layer on the flexible display device by a melted extrusion method for multiple times and cooling the material to form the protection layer. 
     In an example, the material for the sacrifice layer is one of a-Si, silicon oxide, silicon nitride and indium tin oxide (ITO). 
     In an example, the step of irradiating the sacrifice layer with laser to separate the base substrate from the components of the flexible display device comprising: absorbing the components of the flexible display device and rotating the flexible display device by 180 degrees by using a vacuum absorption manipulator, and then irradiating the sacrifice layer with laser to separate the components of the flexible display device from the base substrate. 
     In an example, the base substrate is a glass substrate. 
     According to embodiments of the present invention, a flexible display device is provided. The flexible display device is made using any one of the methods described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to clearly illustrate the technical solution of the embodiments of the invention, the drawings of the embodiments will be briefly described in the following; it is obvious that the described drawings are only related to some embodiments of the invention and thus are not limitative of the invention. 
         FIGS. 1 a  to 1 d    show schematic views of a display device structure corresponding to a manufacturing process of a flexible display device provided in embodiments of the present invention. 
       
         
           
             
                 
               
                 
                     
                 
                 
                   Labels in the drawings: 
                 
                 
                     
                 
               
              
                 
                     
                 
              
             
             
                 
                 
              
                 
                   1-base substrate 
                   2-sacrifice layer 
                 
                 
                   3-components of the flexible display device 
                   4-vacuum absorption 
                 
                 
                     
                   manipulator 
                 
                 
                   5-extrusion and coating apparatus 
                   6-protection layer 
                 
                 
                     
                 
              
             
           
         
       
     
    
    
     DETAILED DESCRIPTION 
     In order to make objects, technical details and advantages of the embodiments of the invention apparent, the technical solutions of the embodiments will be described in a clearly and fully understandable way in connection with the drawings related to the embodiments of the invention. Apparently, the described embodiments are just a part but not all of the embodiments of the invention. Based on the described embodiments herein, those skilled in the art can obtain other embodiment(s), without any inventive work, which should be within the scope of the invention. 
     A known adhesion-peeling method includes: forming a sacrifice layer on a glass substrate; disposing a flexible substrate on the sacrifice layer; then forming components of the flexible display device on the flexible substrate; afterwards, separating the flexible display device, the sacrifice layer and the glass substrate with laser; and finally pressing and coating a protection layer on the flexible substrate to form the flexible display device. 
     However, during the pressing and coating of the protection layer, a coating machine is usually used to press and coat the protection layer that is attached with back glues on the flexible display device. The pressing and coating process may easily damage the components inside the flexible display device and cause creation of air bubbles, which produces pressure on the flexible display device and results in damage on one or more particular components of the flexible display device. Therefore, quality of the entire flexible display device may be affected. 
     Embodiment 1 
     According to embodiments of the present invention, a method for manufacturing flexible display devices is provided, comprising:
         step S 101 : forming a sacrifice layer on a base substrate;   step S 102 : forming a flexible substrate on the sacrifice layer;   step S 103 : forming components of a flexible display device on the flexible substrate;   step S 104 : irradiating the sacrifice layer with laser to separate the base substrate from the flexible substrate; and   step S 105 : coating a material used to make a protection layer on the flexible substrate by a melted extrusion method for multiple times and cooling the material to form the protection layer.       

     In the method of manufacturing flexible display devices provided in embodiments of the present invention, a melted extruding and coating method is applied to form the protection layer. Compared to forming the protection layer using the known pressing and coating method, pressure on components inside the flexible display device is reduced. Therefore, potential damage on the components inside the flexible display device is reduced and creation of air bubbles between film layers is avoided. In addition, it is convenient to adjust a thickness of the protection layer by using the melted extruding and coating method. 
     Thus, the method of manufacturing flexible display devices provided in embodiments of the present invention can improve production efficiency of flexible display devices and quality of the flexible display devices. 
     In an example, a thickness of the protection layer is controlled by a number of coating layers. For example, the thickness of the protection layer is 10-150 micrometers. 
     In an example, various materials are used for the sacrifice layer, as long as the materials are easy to be removed. For example, the material for the sacrifice layer is one of a-Si (amorphous silicon), silicon oxide, silicon nitride and ITO. 
     In an example, the step S 104  comprises: absorbing the components of the flexible display device and rotating the flexible display device by 180 degrees using a vacuum absorption manipulator; and irradiating the sacrifice layer with laser to separate the flexible substrate from the base substrate. After rotation of the flexible display device by 180 degrees, the components of the flexible display device are located at the bottom. When irradiating the sacrifice layer with laser, the sacrifice layer may be removed and the flexible substrate may be separated from the base substrate. In the step S 105 , the protection layer is coated on the flexible substrate. 
     In an example, various materials are used for the base substrate. For example, the base substrate is a glass substrate. 
     Embodiment 2 
       FIGS. 1 a  to 1 d    show schematic views of a display device structure corresponding to a manufacturing process of a flexible display device provided in embodiments of the present invention. Referring to  FIGS. 1 a    to  1   d,  the method for manufacturing flexible display devices provided in embodiments of the present invention comprises:
         step S 201 : forming a sacrifice layer  2  on a base substrate  1 ;   step S 202 : forming components  3  of a flexible display device on the sacrifice layer  2 , as illustrated in  FIG. 1   a;      step S 203 : irradiating the sacrifice layer  2  with laser to separate the base substrate  1  from the components  3  of the flexible display device, as illustrated in  FIG. 1   b;          
     step S 204 : coating a material used to make a protection layer on the flexible display device by a melted extrusion method for multiple times and cooling the material to form the protection layer  6 , as illustrated in  FIG. 1   c.  For example, the material used to form the protection layer  6  is melted first, and then the melted material is coated on the flexible display device using an extruding and coating apparatus  5 . 
     The flexible display device manufactured by performing the steps described above is illustrated in  FIG. 1   d.    
     Comparing Embodiment 2 to Embodiment 1, the step of forming the flexible substrate in Embodiment 1 is omitted, and the components  3  of the flexible display device are formed directly on the sacrifice layer  2 . Thus, a total time for manufacturing the flexible display device is reduced because the additional time needed to cure the flexible substrate to become a film during the manufacture of the flexible substrate is omitted. Besides, the flexible substrate has a yellow color, which may be detrimental for the formation of the components of a bottom-emitting flexible display device. 
     In an example, a thickness of the protection layer is controlled by a number of coating layers. For example, the thickness of the protection layer is 10-150 micrometers. 
     In an example, various materials are used for the sacrifice layer, as long as the materials are easy to be removed. For example, the material for the sacrifice layer is one of a-Si, silicon oxide, silicon nitride and ITO. 
     In an example, the step S 203  comprises: absorbing the components  3  of the flexible display device and rotating the flexible display device by 180 degrees using a vacuum absorption manipulator  4 ; and irradiating the sacrifice layer  2  with laser to separate the components  3  of the flexible display device from the base substrate  1 . After rotation of the flexible display device by 180 degrees, the components  3  of the flexible display device are located at the bottom. When irradiating the sacrifice layer  2  with laser, the sacrifice layer  2  is removed and the components  3  of the flexible display device are separated from the base substrate  1 . In the step S 204 , the protection layer is coated on a side of the components  3  that was attached to the sacrifice layer  2 . 
     In an example, various materials are used for the base substrate  1 . For example, the base substrate is a glass substrate. 
     Embodiment 3 
     The embodiment of the present invention provides a flexible display device that is manufactured by using any one of methods described above with reference to Embodiment 1 and Embodiment 2. Because pressure on components inside a flexible display device can be reduced by using any one of the methods described above, potential damage on the components inside the flexible display device is reduced and creation of air bubbles between film layers is avoided. Thus, the flexible display device manufactured by any one of the methods described above have a better quality. 
     What is described above is related to the illustrative embodiments of the disclosure only and not limitative to the scope of the disclosure; the scopes of the disclosure are defined by the accompanying claims. 
     The present application claims the priority of Chinese patent application No. 201410415163.6 filed on Aug. 21, 2014, the disclosure of which is incorporated herein by reference in its entirety.