Patent Publication Number: US-2020295282-A1

Title: Display device and manufacturing method thereof

Description:
FIELD OF INVENTION 
     The present disclosure relates to a display device, and in particular to a display device with an active matrix organic light emitting diode. 
     BACKGROUND OF INVENTION 
     Organic light emitting diode (OLED) displays are self-luminous displays. According to the driving method, they can be divided into passive matrix driving organic light emitting diode (PMOLED) displays and active matrix driving organic light emitting diode (AMOLED) displays. AMOLED displays have advantages, such as low manufacturing cost, fast response times, power savings, DC drive for portable devices, and a wide operating temperature range. Therefore, more and more AMOLED displays are used in a variety of displays with high performance. 
     Further, in the display device of the AMOLED display, a first flexible substrate layer, a buffer layer and a second flexible substrate layer are disposed on a glass substrate. Then the glass substrate peeled by laser, and a back plane is attached, wherein the first flexible substrate layer and the second flexible substrate layer can be an organic polyimide film, and the buffer layer is an inorganic layer (SiOx). 
     However, for display devices with a two-layer organic polyimide film, the adhesion ability of the organic polyimide film to the inorganic layer is limited. A neutral axis of a bending region of the display device is disposed on a metal axis layer that is susceptible to bending. Therefore, separation of the organic polyimide film from the inorganic layer is apt to occur at a starting position, an intermediate position, and an ending position of the bending region. 
     As a result, it is necessary to provide a display device and a manufacturing method of the display device to solve the problems existing in the conventional technologies, as described above. 
     SUMMARY OF THE INVENTION 
     An object of the present disclosure is to provide a display device and a manufacturing method thereof, wherein a risk of a first flexible substrate layer and a second flexible substrate layer being separated from a buffer layer is reduced by forming the pattern in a bending region of the buffer layer. 
     To achieve the above objects, the present disclosure provides a display device, and the display device comprises a first flexible substrate layer, at least one buffer layer, and a second flexible substrate layer. The second flexible substrate layer is formed on the buffer layer, and the buffer layer is formed on the first flexible substrate layer; a bending region of the buffer layer is formed with a patterned pattern such that the first flexible substrate layer is attached to the second flexible substrate layer through the pattern, and a material of the first flexible substrate layer and the second flexible substrate layer is polyimide. 
     In one embodiment of the present disclosure, the pattern is formed with a plurality of holes. 
     In one embodiment of the present disclosure, the holes are circular, vertical elliptical, transversely elliptical, square, equilateral, or inverted triangles. 
     In one embodiment of the present disclosure, the bending region of the buffer layer includes two corresponding sides, and a diameter of the hole located at two corresponding sides of the bending region is greater than a diameter of the hole located at a middle of the bending region. 
     In one embodiment of the present disclosure, the display device further includes a first back plane and a second back plane, and the first flexible substrate layer is disposed on the first back plane and the second back plane; a bending space is formed between the first back plane and the second back plane, and the bending region of the buffer layer corresponds to the bending space. 
     In one embodiment of the present disclosure, an inner surface of the second flexible substrate layer is attached to an outer surface of the buffer layer, an inner surface of the buffer layer is attached to an outer surface of the first flexible substrate layer, and the first back plane and the second back plane are attached to an inner surface of the first flexible substrate layer. 
     In one embodiment of the present disclosure, the display device further includes a panel, and an inner surface of the panel is attached to an outer surface of the second flexible substrate layer. 
     In one embodiment of the present disclosure, the display device further includes a stiffener, and the stiffener is disposed between the first back plane and the second back plane. 
     To achieve the above objects, the present disclosure provides a manufacturing method of a display device, and the manufacturing method comprises a first flexible substrate layer forming step, a buffer layer forming step, a second flexible substrate layer forming step, and a bending step. The first flexible substrate layer forming step is to form a first flexible substrate layer; the buffer layer forming step is to forme a buffer layer on the first flexible substrate later, wherein a bending region of the buffer layer is formed with a patterned pattern; the second flexible substrate layer forming step is to form a second flexible substrate layer on the buffer layer; the bending step is to bend the bending region of the buffer layer such that the first flexible substrate layer is attached to the second flexible substrate layer through the pattern. 
     In one embodiment of the present disclosure, in the buffer layer forming step, the pattern is formed with a plurality of holes, and the holes are circular, vertical elliptical, transversely elliptical, square, equilateral, or inverted triangles. 
     To achieve the above objects, the present disclosure provides a display device, and the display device comprises a first flexible substrate layer, at least one buffer layer, and a second flexible substrate layer. The the second flexible substrate layer is formed on the buffer layer, and the buffer layer is formed on the first flexible substrate layer; a bending region of the buffer layer is formed with a patterned pattern such that the first flexible substrate layer is attached to the second flexible substrate layer through the pattern. 
     In one embodiment of the present disclosure, the pattern is formed with a plurality of holes. 
     In one embodiment of the present disclosure, the holes are circular, vertical elliptical, transversely elliptical, square, equilateral, or inverted triangles. 
     In one embodiment of the present disclosure, the bending region of the buffer layer includes two corresponding sides, and a diameter of the hole located at two corresponding sides of the bending region is greater than a diameter of the hole located at a middle of the bending region. 
     In one embodiment of the present disclosure, the display device further includes a first back plane and a second back plane, and the first flexible substrate layer is disposed on the first back plane and the second back plane; a bending space is formed between the first back plane and the second back plane, and the bending region of the buffer layer corresponds to the bending space. 
     In one embodiment of the present disclosure, an inner surface of the second flexible substrate layer is attached to an outer surface of the buffer layer, an inner surface of the buffer layer is attached to an outer surface of the first flexible substrate layer, and the first back plane and the second back plane are attached to an inner surface of the first flexible substrate layer. 
     In one embodiment of the present disclosure, the display device further includes a panel, and an inner surface of the panel is attached to an outer surface of the second flexible substrate layer. 
     In one embodiment of the present disclosure, the display device further includes a stiffener, and the stiffener is disposed between the first back plane and the second back plane. 
     As described above, forming the pattern in the buffer layer, the first flexible substrate layer is attached to the second flexible substrate layer through the pattern. The contact area between the first flexible substrate layer and the second flexible substrate layer can be increased. In the bending process of the display device, the risk of the first flexible substrate layer and the second flexible substrate layer being separated from the buffer layer is reduced. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       In order to more clearly illustrate the embodiments or prior art technical solutions embodiment of the present disclosure, will implement the following figures for the cases described in prior art or require the use of a simple introduction. Obviously, the following description of the drawings are only some of those of ordinary skill in terms of creative effort without precondition, you can also obtain other drawings based on these drawings embodiments of the present disclosure. 
         FIG. 1  is a cross-sectional view of a display device according to a preferred embodiment of the present disclosure. 
         FIG. 2  is a top view of a buffer layer of the display device according to a preferred embodiment of the present disclosure. 
         FIG. 3  is a top view of another aspect of the buffer layer of a display device according to a preferred embodiment of the present disclosure. 
         FIG. 4  is a top view of still another aspect of the buffer layer of a display device according to a preferred embodiment of the present disclosure. 
         FIG. 5  is a flowchart of a manufacturing method of a display device according to a preferred embodiment of the present disclosure. 
         FIG. 6  is a schematic view of a first flexible substrate layer forming step of the manufacturing method of a display device according to a preferred embodiment of the present disclosure. 
         FIG. 7  is a schematic view of a buffer layer forming step of the manufacturing method of a display device according to a preferred embodiment of the present disclosure. 
         FIG. 8  is a schematic view of a second flexible substrate layer forming step of the manufacturing method of a display device according to a preferred embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Structure and technical means adopted by the present disclosure to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings. Furthermore, directional terms described by the present disclosure, such as upper, lower, front, back, left, right, inner, outer, side, longitudinal/vertical, transverse/horizontal, etc., are only directions by referring to the accompanying drawings, and thus the used directional terms are used to describe and understand the present disclosure, but the present disclosure is not limited thereto. 
     Referring to  FIG. 1 , a view of a display device according to a preferred embodiment of the present disclosure is illustrated. The display device includes a first flexible substrate layer  2 , a buffer layer  3 , a second flexible substrate layer  4 , a first back plane  5 , and a second back plane  6 . The detailed structure of each component, assembly relationships, and principles of operation in the present invention will be described in detail hereinafter. 
     Referring to  FIG. 1 , the second flexible substrate layer  4  is formed on the buffer layer  3 , the buffer layer  3  is formed on the first flexible substrate layer  2 , and the first flexible substrate layer  2  is formed on the first back plane  5  and the second back plane  6 . A bending space  101  is formed between the first back plane  5  and the second back plane  6 , and a bending region of the buffer layer  3  is formed with a patterned pattern such that the first flexible substrate layer  2  is attached to the second flexible substrate layer  4  through the pattern. In the embodiment, the pattern is formed with a plurality of holes  30 , and the holes  30  are disposed on the bending region  31  of the buffer layer  3  (shown in  FIG. 2 ), wherein the holes  30  correspond to the bending space  101 . 
     Referring to  FIG. 1 , in the embodiment, an inner surface of the second flexible substrate layer  4  is attached to an outer surface of the buffer layer  3 , an inner surface of the buffer layer  3  is attached to an outer surface of the first flexible substrate layer  2 , and the first back plane  5  and the second back plane  6  are attached to an inner surface of the first flexible substrate layer  2 . 
     Referring to  FIG. 1 , the display device further includes a panel  7  and a stiffener  8 , wherein an inner surface of the panel  7  is attached to an outer surface of the second flexible substrate layer  4 , and the panel  7  is an active matrix organic light emitting diode (AMOLED) screen in the embodiment. In other embodiment, the second flexible substrate layer  4  and the panel  7  can be replaced with a structure of a relevant layer of a liquid crystal display, which is not limited by this embodiment. In addition, the stiffener  8  is disposed between the first back plane  5  and the second back plane  6 , and the stiffener  8  is configured to prevent a bending angle between the first back plane  5  and the second back plane  6  from being too small to avoid metal wire breakage of the panel  7 . 
     Referring to  FIGS. 1 and 2 , in the embodiment, the holes  30  are circular, vertical elliptical, transversely elliptical, square, equilateral, or inverted triangles (not shown). In the other embodiment, the bending region  31  of the buffer layer  3  includes two corresponding sides, and a diameter A of the hole  30  located at two corresponding sides of the bending region  31  is greater than a diameter B of the hole  30  located at a middle of the bending region  31  (shown in  FIG. 3  or  FIG. 4 ). In addition, a material of the buffer layer  3  is silicon oxide, and a material of the first flexible substrate layer and the second flexible substrate layer is polyimide. 
     As described above, forming a plurality of holes  30  of the pattern in the buffer layer  3 , the first flexible substrate layer  2  is attached to the second flexible substrate layer  4  through the pattern. The contact area between the first flexible substrate layer  2  and the second flexible substrate layer  4  can be increased. Simultaneously, reducing the contact area of the first flexible substrate layer  2  and the buffer layer  3  and the contact area of the second flexible substrate layer  4  and the buffer layer  3 . In the bending process of the display device, the risk of the first flexible substrate layer  2  and the second flexible substrate layer  4  being separated from the buffer layer  3  is reduced. In addition, in the bending process, the design of the hole  30  with the diameter A and the hole  30  with the diameter B can further improve the reliability of the bending region  31  when bending. 
     Referring to  FIG. 5  in conjunction with  FIG. 6 , a flowchart of a manufacturing method of a display device according to a preferred embodiment of the present disclosure is illustrated, wherein the manufacturing method includes a first flexible substrate layer forming step S 201 , a buffer layer forming step S 202 , a second flexible substrate layer forming step S 203 , a panel forming step S 204 , a back plane bonding step S 205 , and a bending step S 206 . The detailed principles of operation for the present invention will be described in detail hereinafter. 
     Referring to  FIG. 5  in conjunction with  FIG. 6 , in the first flexible substrate layer forming step S 201 , a first flexible substrate layer  2  is formed on a glass substrate  102 . In the embodiment, a material of the first flexible substrate layer  2  is polyimide. 
     Referring to  FIG. 5  in conjunction with  FIG. 7 , in the buffer layer forming step S 202 , the buffer layer  3  is formed on the first flexible substrate layer  2 , and a bending region  31  of the buffer layer  3  is formed with a patterned pattern. In the embodiment, the pattern is formed with a plurality of holes  30 , and the holes  30  are disposed on the bending region  31  of the buffer layer  3 , wherein a material of the buffer layer  3  is silicon oxide. 
     Referring to  FIG. 5  in conjunction with  FIG. 8 , in the second flexible substrate layer forming step S 203 , the second flexible substrate layer  4  is formed on the buffer layer  3 . In the embodiment, a material of the second flexible substrate layer  4  is polyimide. 
     Referring to  FIG. 5  in conjunction with  FIG. 1 , in the panel forming step S 204 , a panel  7  is formed on the second flexible substrate layer  4 . In the embodiment, the panel  7  is an active matrix organic light emitting diode (AMOLED) screen, wherein the manufacturing process of the panel  7  is prior art, and thus will not be further described. 
     Referring to  FIG. 5  in conjunction with  FIG. 1 , in the back plane bonding step S 205 , the glass substrate  102  is removed. In the embodiment, the glass substrate  102  is peeled off from the first flexible substrate layer  2  by a laser lift off technique (LLO), and then a first back plane  5  and a second back plane  6  are attached to an inner surface of the first flexible substrate layer  2 . 
     Referring to  FIG. 5  in conjunction with  FIG. 1 , in the bending step S 206 , the second back plate  6  is bent toward the first back plate  5 , and the bending region  31  of the buffer layer  3  is bent simultaneously such that the first flexible substrate layer  2  is attached to the second flexible substrate layer  4  by the pattern. A stiffener  8  is then disposed between the first back plate  5  and the second back plate  6  to form the display device. In the embodiment, a bending space  101  is formed between the first back plate  5  and the second back plate  6 , and the holes  30  correspond to the bending space  101 . 
     As described above, forming a plurality of holes  30  of the pattern in the buffer layer  3 , the first flexible substrate layer  2  is attached to the second flexible substrate layer  4  through the pattern. The contact area between the first flexible substrate layer  2  and the second flexible substrate layer  4  can be increased. Simultaneously, reducing the contact area of the first flexible substrate layer  2  and the buffer layer  3  and the contact area of the second flexible substrate layer  4  and the buffer layer  3 . In the bending process of the display device, the risk of the first flexible substrate layer  2  and the second flexible substrate layer  4  being separated from the buffer layer  3  is reduced. In addition, in the bending process, the design of the hole  30  with the diameter A and the hole  30  with the diameter B can further improve the reliability of the bending region  31  when bending. 
     The present disclosure has been described with preferred embodiments thereof and it is understood that many changes and modifications to the described embodiments can be carried out without departing from the scope and the spirit of the disclosure that is intended to be limited only by the appended claims.