Patent Publication Number: US-2022238820-A1

Title: Flexible display panel, method for forming the same and adhesive application device for the method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims a priority of the Chinese patent application No. 202110116426.3 filed on Jan. 28, 2021, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to the field of display panel, in particular to a flexible display panel, a method for forming the flexible display panel and an adhesive application device for the method. 
     BACKGROUND 
     Along with the development of the display technology, an electronic product has gradually shown such a trend of being miniaturized, light and thin, and thereby an Organic Light-Emitting Diode (OLED) flexible display panel has been rapidly developed. As compared with a conventional flat-panel display, a most prominent advantage of a flexible display lies in that it has broken through an inherent concept of original two-dimension display, so the flexible display is capable of being applied to more aspect of living scenario and portable devices. 
     SUMMARY 
     In one aspect, the present disclosure provides in some embodiments a flexible display panel, including a cover plate layer and a screen film layer. The screen film layer includes a plurality of film layers laminated one on another at one side of the cover plate layer, and an adhesive is filled into a gap between an edge of an outermost film layer of the screen film layer relative to the cover plate layer and the cover plate layer. 
     In a possible embodiment of the present disclosure, the screen film layer comprises a first bending portion and a first non-bending portion, the cover plate layer comprises a second bending portion and a second non-bending portion, and an edge of the screen film layer and an edge of the cover plate layer are arranged adjacent to the first bending portion of the screen film layer and the second bending portion of the cover plate layer respectively. 
     In a possible embodiment of the present disclosure, projections of at least two film layers of the plurality of film layers onto the cover plate layer partially overlap each other. 
     In a possible embodiment of the present disclosure, the screen film layer includes a polarizer, a display film, a back film and a heat dissipation layer laminated one on another in a direction away from the cover plate layer, and the adhesive covers each of edges of the polarizer, the display film, the back film and the heat dissipation layer. 
     In a possible embodiment of the present disclosure, the screen film layer includes a polarizer, a display film and a back film laminated one on another in a direction away from the cover plate layer, and the adhesive is arranged between the back film and the cover plate layer and covers each of edges of the polarizer and the display film. 
     In a possible embodiment of the present disclosure, the screen film layer includes a polarizer, a display film, a back film and a heat dissipation layer laminated one on another in a direction away from the cover plate layer, and the adhesive is arranged between the heat dissipation layer and the cover plate layer and covers each of edges of the polarizer, the display film and the back film. 
     In another aspect, the present disclosure provides in some embodiments a method for forming a flexible display panel. The flexible display panel includes a cover plate layer and a screen film layer, and the screen film layer includes a plurality of film layers. The method includes: attaching the plurality of film layers sequentially onto one side of the cover plate layer; and applying an adhesive into a gap between an edge of an outermost film layer of the screen film layer relative to the cover plate layer and the cover plate layer. 
     In a possible embodiment of the present disclosure, subsequent to applying the adhesive into the gap between the edge of the outermost film layer of the screen film layer relative to the cover plate layer and the cover plate layer, the method further includes: bending the cover plate layer and the screen film layer. The bent screen film layer includes a first bending portion and a first non-bending portion, the bent cover plate layer includes a second bending portion and a second non-bending portion, and an edge of the screen film layer and an edge of the cover plate layer are arranged adjacent to the first bending portion of the screen film layer and the second bending portion of the cover plate layer respectively. 
     In a possible embodiment of the present disclosure, projections of at least two film layers of the plurality of film layers onto the cover plate layer partially overlap each other. 
     In a possible embodiment of the present disclosure, the screen film layer includes a polarizer, a display film, a back film and a heat dissipation layer laminated one on another in a direction away from the cover plate layer. The applying the adhesive into the gap between the edge of the outermost film layer of the screen film layer relative to the cover plate layer and the cover plate layer includes: applying the adhesive into a gap between an edge of the heat dissipation layer and the cover plate layer in such a manner that the adhesive covers each of edges of the polarizer, the display film, the back film and the heat dissipation layer. 
     In a possible embodiment of the present disclosure, the screen film layer includes a polarizer, a display film and a back film laminated one on another in a direction away from the cover plate layer. The applying the adhesive into the gap between the edge of the outermost film layer of the screen film layer relative to the cover plate layer and the cover plate layer includes: applying the adhesive into a gap between an edge of the back film and the cover plate layer in such a manner that the adhesive covers each of edges of the polarizer and the display film. The screen film layer further includes a heat dissipation layer, and the method further includes attaching the heat dissipation layer onto a side of the back film away from the cover plate layer. 
     In a possible embodiment of the present disclosure, the screen film layer includes a polarizer, a display film and a back film laminated one on another in a direction away from the cover plate layer. The applying the adhesive into the gap between the edge of the outermost film layer of the screen film layer relative to the cover plate layer and the cover plate layer includes: applying the adhesive into a gap between an edge of the back film and the cover plate layer in such a manner that the adhesive covers each of edges of the polarizer, the display film and the back film. The screen film layer further includes a heat dissipation layer, and the method further includes attaching the heat dissipation layer onto a side of the back film away from the cover plate layer in such a manner that the adhesive is arranged between the heat dissipation layer and the cover plate layer. 
     In a possible embodiment of the present disclosure, after the application of the adhesive, the method further includes irradiating the adhesive with ultraviolet. 
     In yet another aspect, the present disclosure provides in some embodiments an adhesive application device for a method for forming a flexible display panel. The flexible display panel includes a cover plate layer and a screen film layer, and the screen film layer includes a plurality of film layers laminated one on another at one side of the cover plate layer. The adhesive application device includes a position capturing unit and an adhesive application mechanism. The position capturing unit is configured to obtain position information about an edge of an outermost film layer of the screen film layer relative to the cover plate layer and directly or indirectly transmit the position information to the adhesive application mechanism. The adhesive application mechanism is configured to apply an adhesive into a gap between the edge of the outermost film layer of the screen film layer relative to the cover plate layer and the cover plate layer. 
     In a possible embodiment of the present disclosure, when a bending angle at a bending portion of the flexible display panel is smaller than or equal to 90°, the position capturing unit is directly aligned with the edge of the outermost film layer of the screen film layer relative to the cover plate layer to capture the position information about the edge of the outermost film layer of the screen film layer relative to the cover plate layer. 
     In a possible embodiment of the present disclosure, when a bending angle at a bending portion of the flexible display panel is 180°, the position capturing unit is configured to capture the position information about the edge of the outermost film layer of the screen film layer relative to the cover plate layer through a reflector. 
     In a possible embodiment of the present disclosure, when a bending angle at a bending portion of the flexible display panel is greater than 90° and smaller than 180°, the position capturing unit is directly aligned with the edge of the screen film layer to capture the position information about the edge of the outermost film layer of the screen film layer relative to the cover plate layer, or the position capturing unit is configured to capture the position information about the edge of the outermost film layer of the screen film layer relative to the cover plate layer through a reflector. 
     In a possible embodiment of the present disclosure, the reflector has a planar or curved surface, or a surface having at least two linear portions. 
     In a possible embodiment of the present disclosure, the adhesive application mechanism is a one-piece or split-type mechanism. 
     The other aspects and the advantages of the present disclosure will be given as follows, or will become more apparent, or will be understood through practices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view showing a flexible display panel according to one embodiment of the present disclosure; 
         FIG. 2  is another schematic view showing the flexible display panel according to one embodiment of the present disclosure; 
         FIG. 3  is yet another schematic view showing the flexible display panel according to one embodiment of the present disclosure; 
         FIG. 4  is a schematic view showing the attachment of a cover plate layer, a polarizer, a display film and a back film according to one embodiment of the present disclosure; 
         FIG. 5  is a flow chart of a method for forming the flexible display panel according to one embodiment of the present disclosure; 
         FIG. 6  is another flow chart of the method for forming the flexible display panel according to one embodiment of the present disclosure; 
         FIG. 7  is yet another flow chart of the method for forming the flexible display panel according to one embodiment of the present disclosure; 
         FIG. 8  is still yet another flow chart of the method for forming the flexible display panel according to one embodiment of the present disclosure; 
         FIG. 9  is a schematic view showing an adhesive application device for the method for forming the flexible display panel according to one embodiment of the present disclosure; 
         FIG. 10  is another schematic view showing the adhesive application device according to one embodiment of the present disclosure; 
         FIG. 11  is yet another schematic view showing the adhesive application device according to one embodiment of the present disclosure; 
         FIG. 12  is still yet another schematic view showing the adhesive application device according to one embodiment of the present disclosure; 
         FIG. 13  is still yet another schematic view showing the adhesive application device according to one embodiment of the present disclosure; 
         FIG. 14  is still yet another schematic view showing the adhesive application device according to one embodiment of the present disclosure; 
         FIG. 15  is a schematic view showing a reflector with a curved surface according to one embodiment of the present disclosure; 
         FIG. 16  is a schematic view showing the reflector with a surface having two linear portions according to one embodiment of the present disclosure; 
         FIG. 17  is a schematic view showing the reflector with a surface having more than two linear portions according to one embodiment of the present disclosure; 
         FIG. 18  is a schematic view showing a one-piece adhesive application mechanism according to one embodiment of the present disclosure; 
         FIG. 19  is another schematic view showing the one-piece adhesive application mechanism according to one embodiment of the present disclosure; 
         FIG. 20  is a schematic view showing a split-type adhesive application mechanism according to one embodiment of the present disclosure; and 
         FIG. 21  is another schematic view showing the split-type adhesive application mechanism according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure will be described hereinafter in conjunction with the embodiments and the drawings. Identical or similar reference numbers in the drawings represent an identical or similar element or elements having an identical or similar function. The following embodiments are for illustrative purposes only, but shall not be used to limit the scope of the present disclosure. 
     In the embodiments of the present disclosure, it should be appreciated that, such words as “longitudinal”, “lateral”, “length”, “width”, “thickness”, “on/above”, “under/below”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside” and “outside” may be used to indicate directions or positions as viewed in the drawings, and they are merely used to facilitate the description in the present disclosure, rather than to indicate or imply that a device or member must be arranged or operated at a specific position. 
     Unless otherwise specified, such words as “arrange”, “connect”, “couple” and “fix” may have a general meaning, e.g., the word “connect” may refer to fixed connection, removable connection or integral connection, or mechanical or electrical connection, or direct connection or indirect connection via an intermediate component, or communication between two components, or an interaction relationship between two components. The meanings of these words may be understood by a person skilled in the art in accordance with the practical applications. 
     In the related art, an OLED device is susceptible to moisture and oxygen, and thereby pixels are damaged and its service life is shortened. Through an encapsulation technique, it is able to protect the OLED device from moisture and oxygen. After a screen is bent to be attached onto a surface of a glass cover plate, such film layers as a polarizer, a display film and a back film are harder to be deformed due to tension and compression as compared with adhesive layers therebetween. In addition, these film layers are bent at different bending radiuses. Hence, when the polarizer, the display film and the back film are bent, misplacement may occur. At this time, a gap is formed between the outermost back film and the glass cover plate, and thereby an overhanging structure is formed. When an edge of the screen is pressed, it is easily bent to generate cracks. The cracks at the film layers extend to the display area, and thereby an encapsulation layer is damaged. 
     The present disclosure provides in some embodiments a flexible display panel  10 , a method for forming the flexible display panel  10  and an adhesive application device for the method, which will be described hereinafter in conjunction with  FIGS. 1 to 21 . 
     As shown in  FIGS. 1 to 3 , the flexible display panel  10  in the embodiments of the present disclosure includes a cover plate layer  1  and a screen film layer  2 . The screen film layer  2  includes a plurality of film layers laminated one on another at one side of the cover plate layer  1 . An adhesive  4  is filled into a gap between an edge of an outermost film layer (e.g., a heat dissipation layer  24  in  FIGS. 1 to 3 ) of the screen film layer  2  relative to the cover plate layer and the cover plate layer  1 . 
     Generally, there is the gap between the edge of the outermost film layer of the screen film layer  2  and the cover plate layer  1 , and the adhesive  4  is filled into the gap so as to provide a support. In this way, even when the flexible display panel  10  is bent, it is less likely to generate the cracks at an edge of the screen film layer  2 , and thereby it is able to prevent the encapsulation layer from being damaged. 
     According to the flexible display panel  10  in the embodiments of the present disclosure, the edge of the screen film layer  2  is supported by the adhesive  4 , so it is able to avoid the formation of the overhanging structure between the edge of the screen film layer  2  (especially the edge of the outermost film layer of the screen film layer  2 ) and the cover plate layer  1 , and reinforce the connection between film layers of the flexible display panel  10 , thereby to reduce the probability of cracks generated when bending the edge of the screen. 
     As shown in  FIGS. 1 to 3 , the screen film layer comprises a first bending portion and a first non-bending portion, the cover plate layer comprises a second bending portion and a second non-bending portion, and the edge of the screen film layer  2  and an edge of the cover plate layer  1  are arranged adjacent to the first bending portion of the screen film layer  2  and the second bending portion of the cover plate layer  1  respectively. It should be appreciated that, in the case that the screen film layer includes the plurality of film layers, the edge of the screen film layer refer to edges of the plurality of film layers including the edge of the outermost film layer of the screen film layer relative to the cover plate layer. 
     As shown in  FIGS. 1 to 3 , projections of at least two film layers of the plurality of film layers onto the cover plate layer  1  partially overlap each other. It should be appreciated that projections of at least two film layers onto the second bending portion of the cover plate layer  1  refer to projections of at least two film layers onto the second bending portion of the cover plate layer  1  along a normal direction of the second bending portion. 
     As shown in  FIG. 1 , the screen film layer  2  includes a polarizer  21 , a display film  22 , a back film  23  and a heat dissipation layer  24  laminated one on another in a direction away from the cover plate layer  1 , and the adhesive  4  covers each of edges of the polarizer  21 , the display film  22 , the back film  23  and the heat dissipation layer  24 . 
     As shown in  FIGS. 1 to 3 , the polarizer  21  is arranged adjacent to the cover plate layer  1 , the back film  23  is arranged away from the cover plate layer  1 , the display film  22  is arranged between the polarizer  21  and the back film  23 , and the heat dissipation layer  24  is arranged at a side of the back film  23  away from the cover plate layer  1 . 
     Based on the above, it is able to support, through the adhesive  4 , the edges of the screen film layer  2  and the heat dissipation layer  24  in a better manner, and improve the connection between the cover plate layer  1  and the screen film layer  2  and between the screen film layer  2  and the heat dissipation layer  24 . 
     As shown in  FIG. 2 , the screen film layer  2  includes a polarizer  21 , a display film  22  and a back film  23  laminated one on another in a direction away from the cover plate layer  1 , and the adhesive  4  is arranged between the back film  23  and the cover plate layer  1  and covers each of edges of the polarizer  21  and the display film  22 . 
     Based on the above, it is able to support, through the adhesive  4 , the edges of the polarizer  21  and the display film  22  in a better manner, and improve the connection between the cover plate layer  1  and the polarizer  21  and between the polarizer  21  and the display film  22 . 
     As shown in  FIG. 3 , the screen film layer  2  includes a polarizer  21 , a display film  22 , a back film  23  and a heat dissipation layer  24  laminated one on another in a direction away from the cover plate layer  1 , and the adhesive  4  is arranged between the heat dissipation layer  24  and the cover plate layer  1  and covers each of edges of the polarizer  21 , the display film  22  and the back film  23 . 
     Based on the above, it is able to support, through the adhesive  4 , the edges of the polarizer  21 , the display film  22  and the back film  23  in a better manner, and improve the connection between the cover plate layer  1  and the polarizer  21 , between the polarizer  21  and the display film  22 , and between the display film  22  and the back film  23 . 
     As shown in  FIG. 4 , adhesive layers are arranged between the cover plate layer  1  and the polarizer  21 , between the polarizer  21  and the display film  22 , and between the display film  22  and the back film  23 , so as to adhere the adjacent layers. The adhesive layer between the cover plate layer  1  and the polarizer  21  is an Optically Clear Adhesive (OCA)  25 , and the adhesive layer between the polarizer  21  and the display film  22  and between the display film  22  and the back film  23  is a Pressure Sensitive Adhesive (PSA)  26 . 
     In a possible embodiment of the present disclosure, the OCA  25  has a thickness of 140 μm to 160 μm, and the PSA  26  has a thickness of 15 μm to 20 μm. 
     The present disclosure further provides a method for a forming flexible display panel  10 . As shown in  FIGS. 1 to 4 , the flexible display panel  10  includes a cover plate layer  1  and a screen film layer  2 , and the screen film layer  2  includes a plurality of film layers. As shown in  FIG. 5 , the method includes the following steps, i.e., S 1  and S 2 . 
     S 1 , attaching the plurality of film layers sequentially onto one side of the cover plate layer. 
     S 2 , applying an adhesive into a gap between an edge of an outermost film layer of the screen film layer relative to the cover plate layer and the cover plate layer. 
     It should be appreciated that a molding process for the flexible display panel may be a general term of the method for forming the flexible display panel. 
     In some embodiments, subsequent to applying the adhesive into the gap between the edge of the outermost film layer of the screen film layer relative to the cover plate layer and the cover plate layer, the method further includes: bending the cover plate layer and the screen film layer. The bent screen film layer includes a first bending portion and a first non-bending portion, the bent cover plate layer includes a second bending portion and a second non-bending portion, and an edge of the screen film layer and an edge of the cover plate layer are arranged adjacent to the first bending portion of the screen film layer and the second bending portion of the cover plate layer respectively. 
     In some embodiments, projections of at least two film layers of the plurality of film layers onto the cover plate layer partially overlap each other. 
     As shown in  FIGS. 1 to 4 , the screen film layer  2  includes a polarizer  21 , a display film  22 , a back film  23  and a heat dissipation layer  24  laminated one on another in a direction away from the cover plate layer. The applying the adhesive into the gap between the edge of the outermost film layer of the screen film layer relative to the cover plate layer  1  and the cover plate layer includes: applying the adhesive into a gap between an edge of the heat dissipation layer and the cover plate layer in such a manner that the adhesive covers each of edges of the polarizer, the display film, the back film and the heat dissipation layer. 
     In some embodiments of the present disclosure, the screen film layer  2  includes a polarizer  21 , a display film  22  and a back film  23  laminated one on another in a direction away from the cover plate layer  1 . The applying the adhesive into the gap between the edge of the outermost film layer of the screen film layer  2  relative to the cover plate layer  1  and the cover plate layer  1  includes: applying the adhesive into a gap between an edge of the back film  23  and the cover plate layer  1  in such a manner that the adhesive covers each of edges of the polarizer and the display film. The screen film layer further includes a heat dissipation layer  24 , and the method further includes attaching the heat dissipation layer  24  onto a side of the back film  23  away from the cover plate layer. 
     In some embodiments of the present disclosure, the screen film layer  2  includes a polarizer  21 , a display film  22  and a back film  23  laminated one on another in a direction away from the cover plate layer. The applying the adhesive into the gap between the edge of the outermost film layer of the screen film layer  2  relative to the cover plate layer  1  and the cover plate layer  1  includes: applying the adhesive into a gap between an edge of the back film and the cover plate layer in such a manner that the adhesive covers an edge of the screen film layer, The screen film layer further includes a heat dissipation layer  24 , and the method further includes attaching the heat dissipation layer onto a side of the back film away from the cover plate layer  1  in such a manner that the adhesive  4  is arranged between the heat dissipation layer  24  and the cover plate layer  1 . 
     In other words, the adhesive is applied prior to the attachment of the polarizer, the display film and the back film and subsequent to the attachment of the heat dissipation layer, or subsequent to the attachment of the heat dissipation layer, at each of the edges of the polarizer, the display film, the back film and the heat dissipation layer, or merely at each of the edges of the polarizer, the display film and the back film, or merely at each of the edges of the polarizer and the display film. 
     According to the method in the embodiments of the present disclosure, the flexible display panel is provided with the adhesive at the edge, and when the resultant flexible display panel is bent, it is able to avoid the occurrence of cracks at the edge, thereby to prevent an encapsulation layer from being damaged. The method is used to obtain the above-mentioned flexible display panel. 
     After the application of the adhesive, the method further includes S 3 . 
     S 3 , irradiating the adhesive with ultraviolet. 
     In this way, it is able to cure the adhesive and increase a support capability of the adhesive, thereby to support and protect the edge of the flexible display panel and increase an adhesion strength between the film layers. 
     To be specific, as shown in  FIG. 6 , the method includes the following steps, i.e., S 21 , S 22  and S 23 . 
     S 21 , attaching the polarizer, the display film, the back film and the heat dissipation layer sequentially onto the cover plate layer. 
     S 22 , applying the adhesive into the gap between the edge of the heat dissipation layer and the cover plate layer in such a manner that the adhesive covers each of the edges of the polarizer, the display film, the back film and the heat dissipation layer. 
     S 23 , irradiating the adhesive with ultraviolet. 
     In this way, it is able to obtain the flexible display panel in  FIG. 1 . 
     As shown in  FIG. 7 , the method includes the following steps, i.e., S 31 , S 32 , S 33  and S 34 . 
     S 31 , attaching the polarizer, the display film and the back film sequentially onto the cover plate layer. 
     S 32 , applying the adhesive into the gap between the edge of the back film and the cover plate layer in such a manner that the adhesive covers each of the edges of the polarizer and the display film. 
     S 33 , attaching the heat dissipation layer onto a side of the back film away from the cover plate layer. 
     S 34 , irradiating the adhesive with ultraviolet. 
     In this way, it is able to obtain the flexible display panel in  FIG. 2 . 
     As shown in  FIG. 8 , the method includes the following steps, i.e., S 41 , S 42 , S 43  and S 44 . 
     S 41 , attaching the polarizer, the display film and the back film sequentially onto the cover plate layer. 
     S 42 , applying the adhesive into the gap between the edge of the back film and the cover plate layer in such a manner that the adhesive covers each of the edges of the polarizer, the display film and the display film. 
     S 43 , attaching the heat dissipation layer onto a side of the back film away from the cover plate layer in such manner that the adhesive is arranged between the heat dissipation layer and the cover plate layer. 
     S 44 , irradiating the adhesive with ultraviolet. 
     In this way, it is able to obtain the flexible display panel in  FIG. 3 . 
     The present disclosure further provides in some embodiments an adhesive application device for a method for forming a flexible display panel  10 . As shown in  FIGS. 1 to 4 , the flexible display panel  10  includes a cover plate layer  1  and a screen film layer  2 , and the screen film layer  2  includes a plurality of film layers laminated one on another at one side of the cover plate layer. As shown in  FIGS. 9 to 14 , the adhesive application device includes a position capturing unit  201  and an adhesive application mechanism  202 . The position capturing unit  201  is configured to obtain position information about an edge of an outermost film layer of the screen film layer  2  relative to the cover plate layer  1  and directly or indirectly transmit the position information to the adhesive application mechanism  202 . The adhesive application mechanism  202  is configured to apply an adhesive into a gap between the edge of the outermost film layer of the screen film layer relative to the cover plate layer and the cover plate layer. 
     To be specific, the adhesive application mechanism  202  includes a nozzle  2021  for applying the adhesive to the edge. The nozzle  2021  of the adhesive application mechanism  202  directly moves to the edge of the screen film layer  2 , so as to directly apply the adhesive to the edge. In this way, it is able to solve the problem that it is difficult to apply the adhesive to the edge when a conventional adhesive application mechanism moves in a small space defined by the cover plate layer  1 . 
     According to the adhesive application device in the embodiments of the present disclosure, the position information about the edge of an outermost film layer of the screen film layer  2  relative to the cover plate layer  1  is obtained by the position capturing unit  201 , and then the adhesive is applied to the edge by the adhesive application mechanism  202  in accordance with the position information. As a result, it is able to obtain the flexible display panel  10  having the adhesive  4  at the edge, and prevent the occurrence of cracks at the edge when the resultant flexible display panel  10  is bent, thereby to prevent an encapsulation layer from being damaged. 
     The adhesive application device in the embodiments of the present disclosure is used to implement the above-mentioned method, so as to obtain the above-mentioned flexible display panel  10 . In addition, through obtaining the position information about the edge of the outermost film layer of the screen film layer  2  relative to the cover plate layer  1  by the position capturing unit  201 , it is able to simplify an adhesive application process. 
     As shown in  FIGS. 9 and 10 , when a bending angle at a bending portion of the flexible display panel  10  is smaller than or equal to 90°, the position capturing unit  201  is directly aligned with the edge of the screen film layer  2  to capture the position information about the edge of the screen film layer. 
     In other words, when the bending angle at the bending portion of the flexible display panel  10  is smaller than or equal to 90° (i.e., a flexible screen is arranged horizontally or curved at a small angle), the edge of the screen film layer  2  is easily captured by the position capturing unit  201  directly, so the adhesive is applied in a simple manner. 
     For the flexible display panel  10  having the bending angle smaller than or equal to 90° at the bending portion, during the application of the adhesive, an opening of the cover plate layer  1  faces upward, and the position capturing unit  201  is directly arranged above the edge of the screen film layer  2  to capture the position information about the edge of the outermost film layer of the screen film layer  2  relative to the cover plate layer  1 . A represents an optical path. The adhesive application mechanism  202  has a structure as shown in  FIGS. 9 to 10  to directly apply the adhesive to the edge of the screen film layer  2  in a vertical direction, or has a structure as shown in  FIGS. 18 and 20  to apply the adhesive to the edge of the screen film layer in a horizontal direction. 
     As shown in  FIGS. 11 and 12 , when the bending angle at the bending portion of the flexible display panel  10  is 180°, the position capturing unit  201  is configured to capture the position information about the edge of the outermost film layer of the screen film layer  2  relative to the cover plate layer  1  through a reflector  203 . 
     In other words, when the bending angle at the bending portion of the flexible display panel  10  is 180°, the edge of the screen film layer  2  is easily shielded by ink  11  on the cover plate layer  1  or a planar portion of the cover plate layer  1 , so it is difficult for the position capturing unit  201  to directly capture the edge of the screen film layer  2 . At this time, it is necessary to capture the edge of the screen film layer  2  through the reflector  203 . 
     For the flexible display panel  10  having the bending angle of 180° at the bending portion, during the application of the adhesive, the opening of the cover plate layer  1  faces downward, and the position capturing unit  201  captures the position information about the edge of the outermost film layer of the screen film layer  2  relative to the cover plate layer  1  through the reflector  203 . The position capturing unit  201  on the right is configured to capture a left edge of the screen film layer  2 , and the position capturing unit  201  on the left is configured to capture a right edge of the screen film layer  2 . A represents an optical path. The adhesive application mechanism  202  has a structure as shown in  FIGS. 11 and 12  to apply the adhesive to the edge of the screen film layer  2  in the horizontal direction, or has a structure as shown in  FIGS. 19 and 21  to directly apply the adhesive to the edge of the screen film layer in the vertical direction. 
     As shown in  FIGS. 13 and 14 , when the bending angle at the bending portion of the flexible display panel  10  is greater than 90° and smaller than 180°, the position capturing unit  201  is directly aligned with the edge of the screen film layer  2  to capture the position information about the edge of the outermost film layer of the screen film layer  2  relative to the cover plate layer  1 , or the position capturing unit  201  is configured to capture the position information about the edge of the outermost film layer of the screen film layer  2  relative to the cover plate layer  1  through the reflector  203 . 
     To be specific, when the bending angle at the bending portion approximates to 90°, the position capturing unit  201  is directly aligned with the edge of the screen film layer  2  to capture the position information about the edge of the outermost film layer of the screen film layer  2  relative to the cover plate layer  1 . The position capturing units  201  are arranged in such a manner that the position capturing unit  201  on the right captures the left edge of the screen film layer  2  and the position capturing unit  201  on the left captures the right edge of the screen film layer  2 . When the bending angle at the bending portion approximates to 180°, the position capturing unit  201  captures the position information about the edge of the outermost film layer of the screen film layer  2  relative to the cover plate layer  1  through the reflector  203 . Identically, the position capturing unit  201  on the right captures the left edge of the screen film layer  2 , and the position capturing unit  201  on the left captures the right edge of the screen film layer  2 . 
     For the flexible display panel  10  having the bending angle greater than 90° and smaller than 180° at the bending portion (i.e., the flexible display panel  10  is bent at a large angle), during the application of the adhesive, the opening of the cover plate layer  1  faces upward, and the position capturing unit  201  captures the position information about the edge of the outermost film layer of the screen film layer  2  relative to the cover plate layer  1  through the reflector  203  (as shown in  FIG. 13 ), or the position capturing units  201  are arranged in such a manner that the position capturing unit  201  on the right captures the left edge of the screen film layer  2  and the position capturing unit  201  on the left captures the right edge of the screen film layer  2  (as shown in  FIG. 14 ). A represents an optical path. The adhesive application mechanism  202  has a one-piece structure as shown in  FIGS. 13 and 14  to apply the adhesive to the edge of the screen film layer  2  in the horizontal direction, or has a split-type structure as shown in  FIG. 20  to apply the adhesive to the edge of the screen film layer in the horizontal direction. 
     The opening of the cover plate layer is arranged as shown in  FIGS. 9 to 14 , so as to store the adhesive between the edge of the screen and the cover plate layer  1 , and allow the adhesive to flow into the gap at the edge of the screen. Of course, in some other embodiments of the present disclosure, the opening of the cover plate layer  1  may also be arranged obliquely. In addition, the adhesive  4  is arranged above the ink  11 , so an illumination effect of the flexible display panel  10  is not adversely affected. 
     In a possible embodiment of the present disclosure, the reflector  203  has a planar or curved surface, or a surface having at least two linear portions. 
     For example, as shown in  FIGS. 11 to 13 , the reflector  203  has a planar surface; as shown in  FIG. 15 , the reflector  203  has a curved surface; as shown in  FIG. 16 , the reflector  203  has a surface having two linear portions; and as shown in  FIG. 17 , the reflector  203  has a surface having more than two linear portions. 
     In a possible embodiment of the present disclosure, the adhesive application mechanism  202  is a one-piece or split-type mechanism. 
     For example, as shown in  FIGS. 9, 11, 13-14 and 18-19 , the adhesive application mechanism  202  is a one-piece mechanism; and as shown in  FIGS. 10, 12 and 20-21  is a split-type mechanism. The adhesive application mechanism  202  in  FIG. 9  may also be replaced with the adhesive application mechanism  202  in  FIG. 18 , the adhesive application mechanism  202  in  FIG. 10  may also be replaced with the adhesive application mechanism  202  in  FIG. 20 , the adhesive application mechanism  202  in  FIG. 11  may also be replaced with the adhesive application mechanism  202  in  FIG. 19 , and the adhesive application mechanism  202  in  FIG. 12  may also be replaced with the adhesive application mechanism  202  in  FIG. 21 . 
     The adhesive is an ultraviolet (UV)-curable adhesive. After the application, the adhesive is irradiated with UV, so as to be cured. The UV curing process may be performed simultaneously with a curing process of the OCA  24 . 
     According to the adhesive application device in the embodiments of the present disclosure, for a small bending angle, the position capturing unit  201  directly captures the edge of the screen film layer  2 , and for a large bending angle, the position capturing unit  201  captures the edge of the screen film layer  2  through the reflector  203 , so it is able to accurately apply the adhesive to the edge of the screen film layer  2 . 
     It should be further appreciated that, such phrases as “one embodiment”, “some embodiments”, “an example”, “a specific example” or “some examples” intend to indicate that the features, structures, materials or characteristics are contained in at least one embodiment of the present disclosure, rather than referring to a same embodiment. In addition, the features, structures, materials or characteristics may be combined in any embodiment or embodiments in an appropriate manner. 
     The above embodiments are for illustrative purposes only, but the present disclosure is not limited thereto. Apparently, a person skilled in the art may make further modifications and improvements without departing from the spirit of the present disclosure, and these modifications and improvements shall also fall within the scope of the present disclosure.