Abstract:
The present invention relates to a flexible display panel for suppressing a problem in which a crack such as disconnection on an internal circuit layer or the like is generated or a required warpage level is not attainable in a warped area while bending an edge portion thereof. According to an embodiment of the present invention, the layer structure of a signal line portion for electrically connecting elements provided within a display area and a non-active area may be simplified, and a protective member may be formed thereon, thereby obtaining the effect of minimizing the damage of the layer structure due to bending.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2013-0040072, filed on Apr. 11, 2013 in Republic of Korea, which is hereby incorporated by reference for all purposes as if fully set forth herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a flexible display panel, and more particularly, to a flexible display panel for suppressing a problem in which a crack such as disconnection on an internal circuit layer or the like is generated or a required warpage level is not attainable in a warped area while bending an edge portion thereof. 
         [0004]    2. Description of the Related Art 
         [0005]    In recent years, while interest in information displays has risen and demand for using portable information media has increased, studies on flat panel display devices (FPDs) for replacing the existing display devices such as cathode ray tubes and commercialization thereof have been mostly carried out. 
         [0006]    In such a flat panel display field, though liquid lightweight and low-power liquid crystal display devices have been most noteworthy flat panel display devices up to now, development on new flat panel displays has been actively carried out according to various requirements. 
         [0007]    Since organic light emitting diode (OLED) display devices, which are one of new flat panel displays, are a spontaneous light-emitting type, they have excellent viewing angle and contrast range characteristics but do not require a backlight contrary to liquid crystal displays, and thus allowing a lightweight and low profile device as well as being beneficial in the aspect of power consumption. Furthermore, they have an advantage in low DC voltage drive and high response speed, and also particularly have a beneficial advantage in the aspect of fabrication cost. 
         [0008]    In particular, flexible display devices, which are not likely to be damaged even when folded or rolled up, will be emerged as a new technology in the flat panel display device field, and organic light emitting display devices in which pixel formation is easily made on a flexible plastic substrate are more suitable than liquid crystal displays, mostly using a glass substrate, in implementing a flexible display device with the development of technology. 
         [0009]      FIG. 1  is a view schematically illustrating a flexible display panel with a plastic material substrate used in a flexible display device according to the related art. 
         [0010]    Referring to  FIG. 1 , a flexible display device  1  is formed with an active area (A/A) in which an actual image is implemented on a plastic substrate  10  and a non-active area (N/A) surrounding the active area (A/A). Though not shown in the drawing, a pixel area defined by a plurality of gate lines and data lines is formed in the active area (A/A), a plurality of thin film transistor are formed in the pixel area. 
         [0011]    Furthermore, two gate driving circuits  30  are embedded therein in a gate-in-panel (GIP) structure at the left and right side ends of the non-active area (N/A) of the flexible display device  1 . The gate driving circuit  30  supplies a gate signal to each pixel through a signal line connected to a gate line in the active area (A/A). Furthermore, a data driving circuit  40  connected to a data line on the active area (A/A) is provided at one side of the non-active area (N/A). The data driving circuit  40  is electrically connected to a pad  46  formed at one side end of the flexible display panel  1 . In addition, a polarizing film  60  for compensating the optical characteristics of the flexible display panel  1  is adhered onto a front surface of the active area (A/A). 
         [0012]    In implementing a display device using a flexible display panel with the foregoing structure, there is proposed a structure in which a narrow bezel is implemented by bending at least one side end thereof. 
         [0013]      FIG. 2  is a view for explaining the bending structure of a narrow bezel structured flexible display panel according to the related art. 
         [0014]    Referring to  FIG. 2 , the flexible display device  1  defined by an active area (A/A) formed with a plurality of pixels and a non-active area (N/A) surrounding the active area (A/A) is configured with a form in which a plastic substrate  10  configured with a polyimide or the like, a driving element layer  20  including various signal lines and a plurality of thin film transistors formed on the substrate  10 , a light-emitting element layer  25  formed on the driving element layer  20  to implement an image, a barrier film  40  configured to protect the driving element layer  20  and light-emitting element layer  25  thereunder, and a polarizing film  60  configured to compensate optical characteristics are layered thereon. Furthermore, a supporting film  70  with a polyethylene terephthalate (PET) material for supporting the flexible display panel  1  is further adhered to a lower portion of the substrate  10 . Here, the non-active area (N/A) is not an area for displaying an image, and thus is configured not to include the light-emitting element layer  25 , barrier film  40 , and polarizing film  60 , but configured to include a predetermined signal line and thin film transistor constituting a gate driving circuit in a GIP manner. 
         [0015]    In order to implement a narrow bezel in a flexible display device with the foregoing structure, it is configured such that the non-active area (N/A) is warped in the rear surface direction of the display panel  1 . Here, metals constituting the signal lines and thin film transistors contained in the driving element layer  20  are formed of titanium/aluminum/titanium (Ti/Al/Ti) in case of source/drain electrodes, and formed of molybdenum niobium/aluminum (MoNb/Al) in case of a gate electrode, and a crack is often generated according to a force acting on the driving element layer  20  during the bending process. 
         [0016]    Furthermore, the supporting film  70  adhered to a lower portion of the plastic substrate  10  has a characteristic of not being easily warped compared to the plastic substrate  10 , thereby causing a problem in which the bending structure cannot be maintained as it is during the module process of the display device. 
       SUMMARY OF THE INVENTION 
       [0017]    The present invention is contrived to solve or address the foregoing problems, and an object of the present invention is to provide a flexible display device for warping each side end of the flexible display panel using a plastic substrate to implement a narrow bezel structure as well as minimizing the damage of the signal line, thin film transistor, and the like in a warped area. 
         [0018]    In order to accomplish the foregoing objects, a flexible display panel according to an embodiment of the present invention may include an active area provided with a plurality of pixel having a multi-layer structure; a non-active area configured to surround the active area, and provided with a gate driving circuit having a multi-layer structure; and a substrate defined with a bending area formed between the gate driving circuit and the active area, and at least one lateral surface of which is warped in a rear surface direction thereof, wherein the bending area comprises an auxiliary line formed with one layer for electrically connecting the gate driving circuit to the pixel. 
         [0019]    Furthermore, in order to accomplish the foregoing objects, a flexible display panel according to an embodiment of the present invention may include a substrate defined with an active area and a non-active area comprising a GIP area and a bending area, and the bending area of which is warped in a rear surface direction thereof; a driving element layer formed on the active area and GIP area, respectively, to comprise a thin film transistor connected to the gate line and data line; an auxiliary line formed on the bending area to be electrically connected to the driving element layer; a light-emitting element layer formed to be divided into each pixel on the driving element layer; a first passivation layer formed on the light-emitting element layer; an organic layer formed on the first passivation layer; and a second passivation layer formed on the first passivation layer of the active area, to an upper portion of which a protective film is adhered by an adhesive. 
         [0020]    According to a flexible display device in accordance with an embodiment of the present invention, the layer structure of a signal line portion for electrically connecting elements provided within an active area and a non-active area may be simplified, and a protective member may be formed thereon, thereby obtaining the effect of minimizing the damage of the layer structure due to bending. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The accompanying drawings, which are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
           [0022]    In the drawings: 
           [0023]      FIG. 1  is a view schematically illustrating a flexible display panel with a plastic material substrate used in a flexible display device according to the related art; 
           [0024]      FIG. 2  is a view for explaining the bending structure of a narrow bezel structured flexible display panel according to the related art; 
           [0025]      FIG. 3  is a view illustrating the structure of a flexible display panel according to an embodiment of the present invention; 
           [0026]      FIG. 4  is a cross-sectional view illustrating a portion taken along line IV-IV′ in  FIG. 3 ; 
           [0027]      FIG. 5A  is a view illustrating an example in which a flexible display panel according to an embodiment of the present invention is fixed in a bending structure, and  FIG. 5B  is a view illustrating the cross section of a portion taken along line V-V′ in  FIG. 5A ; and 
           [0028]      FIG. 6A  is a view for explaining a method of processing a flexible display panel according to another embodiment of the present invention, and  FIG. 6B  is a view illustrating a display device structure subsequent to the bending of the processed flexible display panel according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    Hereinafter, a flexible display device according to preferred embodiments of the present invention and a fabrication method thereof will be described with reference to the accompanying drawings. 
         [0030]      FIG. 3  is a view illustrating the structure of a flexible display panel according to an embodiment of the present invention. 
         [0031]    Referring to  FIG. 3 , a flexible display panel  100  according to the present invention is defined with an active area (A/A) configured to display an image on a plastic material substrate  101  having flexibility, and a non-active area (N/A) surrounding the outside of the active area (A/A). 
         [0032]    The active area (A/A) of the flexible display panel  100  is formed with a plurality of pixels (PXs) defined by a plurality of gate lines (not shown) and data lines (not shown) to include at least one thin film transistor. Furthermore, a plurality of power lines (not shown) is formed in parallel to a data line (not shown), and such various signal lines and thin film transistors may form a driving element layer (not shown) on the substrate. A polarizing film  160  for compensating the optical characteristics of the flexible display panel  100  is adhered onto the uppermost layer of the active area (A/A). 
         [0033]    In addition, a gate driving circuit  130  electrically connected to the gate line of the active area (A/A) to provide a gate driving signal is mounted in a GIP manner on the non-active area (N/A) at both side ends of the flexible display panel  100 . 
         [0034]    Furthermore, a data driving circuit  140  providing a data signal is mounted in a COG manner on the non-active area (N/A) at one side end of the flexible display panel  100 . The data driving circuit  140  is electrically connected to an external system through a pad  146  formed on the substrate  101 . 
         [0035]    In particular, the flexible display panel  100  according to the present invention is characterized in that an additional signal line is formed between the gate driving circuit  130  within the non-active area (N/A) and the active area (A/A) to be electrically connected to each other, and a protective layer  150  is formed thereon to minimize the damage of an organic layer, an inorganic layer and other signal lines during the bending of the flexible display panel  100 . 
         [0036]    In other words, a protective layer  150  is further formed in such a manner that an additional signal line (not shown) is formed on the substrate  101  to substitute a layer structure formed between the conventional active area (A/A) and gate driving circuit  130  to simplify the layer structure and minimize a force applied to the signal line (not shown) according to the substrate  101  being warped in the upward direction. 
         [0037]    Hereinafter, the structure of a flexible display panel according to an embodiment of the present invention will be described in more detail with reference to one cross section of the display panel  100 . 
         [0038]      FIG. 4  is a cross-sectional view illustrating a portion taken along line IV-IV′ in  FIG. 3 . 
         [0039]    As illustrated in the drawing, the display panel  100  according to an embodiment of the present invention is divided to an active area (A/A) configured to display an image and a non-active area (N/A) configured to surround the outside of the active area (A/A). 
         [0040]    Each pixel (PX) within the display area (A/A) may include an organic light emitting diode, and at least one switching thin film transistor and driving thin film transistor for controlling the organic light emitting diode. 
         [0041]    Furthermore, a barrier film  147  is positioned in a facing manner for the encapsulation of the pixel (PX) on an entire surface of the substrate, and a polarizing film  160  is adhered to an upper portion of the barrier film  147 . The polarizing film  160  performs the role of preventing image quality from being deteriorated by the reflection of light incident from the outside to the organic light emitting display device. 
         [0042]    A bending area (B/A) is further defined between a GIP area (G/A) including a gate driving circuit on the non-active area (N/A) and the active area (A/A), and an auxiliary line  120  for electrically connecting the GIP area (G/A) to the active area (A/A) and a protective layer  150  for preventing the damage of the auxiliary line  120  due to bending are further formed on the bending area (B/A). 
         [0043]    Here, a material capable of minimizing a force applied to the auxiliary line  120  as each side end thereof is bent is used for the protective layer  150 , and here, the thickness and Young&#39;s modulus of the auxiliary line  120  and substrate  101  may be taken into consideration. 
         [0044]    Referring to  FIG. 4 , a buffer layer (not shown) made of an insulating material, particularly, silicon oxide (SiO 2 ) or silicon nitride (SiNx), which is an inorganic insulating material, may be formed on the substrate  101 . The buffer layer (not shown) is formed to minimize the characteristic deterioration problem of the semiconductor layer  103  due to the emission of alkali ions taken out of the inside of the substrate  101  during the crystallization process of the semiconductor layer  103  which is a subsequent process, and thus can be omitted. 
         [0045]    Furthermore, at least one switching thin film transistor (not shown) and driving thin film transistor (TR 1 ) for controlling an organic light emitting diode is provided at each pixel (PX) within the display area (A/A) on the buffer layer (not shown). Here, a driving thin film transistor (TR 1 ) in pixel is formed along with a GIP thin film transistor (TR 2 ) on the GIP area (G/A). 
         [0046]    Furthermore, a semiconductor layer  103  configured with a first region  103   a  made of pure polysilicon to form a channel at a central portion thereof, and second regions  103   b ,  103   c  into which high concentration impurities are doped at both sides of the first region  103   a  are formed to correspond to each thin film transistor (TR 1 , TR 2 ). 
         [0047]    A gate insulating layer  105  is formed on the buffer layer including the semiconductor layer  103 . 
         [0048]    In addition, a gate electrode  107  is formed to correspond to the first region  103   a  of the semiconductor layer  103  in each thin film transistor (TR 1 , TR 2 ) on the gate insulating layer  105 . 
         [0049]    Furthermore, a gate line (not shown) connected to the gate electrode  107  of the switching thin film transistor (not shown) and extended in one direction is formed on the same layer as that of the gate electrode  107 . Here, the gate electrode  107  and the gate line may be formed with a single layer structure made of a first metal material, for example, any one of aluminum (Al), aluminum alloy (AlNd), molybdenum (Mo) and molybdenum titanium (MoTi) or formed with a double or triple layer structure made of two or more first metal materials. 
         [0050]    In addition, the auxiliary line  120  is further formed around the bending area (B/A) during the formation of the gate electrode  107  and gate line. The auxiliary line  120  is extended to the active area (A/A) and non-active area (N/A) to electrically connect the driving thin film transistor (TR 1 ) to the GIP thin film transistor (TR 2 ). On the drawing, it is illustrated an example in which the auxiliary line  120  connects the source of the driving thin film transistor (TR 1 ) to the drain of the GIP thin film transistor (TR 2 ), but the detailed connecting structure may be different from the drawing according to the circuit structure. 
         [0051]    Furthermore, on the drawing, it is illustrated an example in which the auxiliary line  120  is formed through the same metal as that of the gate line and gate electrode  107 , but the auxiliary line  120  may be formed using the source/drain metal which will be described later other than the gate metal. 
         [0052]    Moreover, the auxiliary line  120  may be formed using an additional metal having flexibility other than the gate metal or source/drain metal. The auxiliary line  120  is a portion being warped during the bending of the flexible display panel  100 , and thus a metal with a flexible material may be used, rather than typically used gate metals or source/drain metals to minimize damage. Accordingly, when the auxiliary line  120  is formed using a flexible copper (Cu) or copper alloy other than the foregoing metal, it may be possible to reduce a rate of damage due to bending. 
         [0053]    In addition, an interlayer insulating layer  109  made of an insulating material, for example, silicon oxide (SiO 2 ) or silicon nitride (SiNx), which is an inorganic insulating layer, is formed on an entire surface of the active area of the substrate including the gate electrode  107  and gate line. Here, a semiconductor layer contact hole (not shown) for exposing the second regions  103   b ,  103   c , respectively, positioned at both sides of the first region  103   a  of each semiconductor layer  103  is formed on the interlayer insulating layer  109  and the gate insulating layer  105  thereunder. 
         [0054]    A data line crossed with a scan line to define a pixel (PX) is formed on the interlayer insulating layer  109  including the semiconductor layer contact hole. Here, the data line and power supply line may be any one of aluminum (Al), aluminum alloy (AlNd), molybdenum (Mo), molybdenum titanium (MoTi), chromium (Cr) and titanium (Ti) or a combination of two or more thereof. 
         [0055]    In addition, a source electrode  113   a  and a drain electrode  113   b  brought into contact with the second regions  103   b ,  103   c , respectively, exposed through the semiconductor layer contact hole (not shown) and made of a second metal material as that of the data line are formed in each transistor region on the interlayer insulating layer  109 . Here, the sequentially layered semiconductor layer  103 , gate insulating layer  105  and the gate electrode  107  and interlayer insulating layer  109  and the source electrode  113   a  and drain electrode  113   b  formed to be separated from each other form a driving thin film transistor (TR 1 ), and a GIP thin film transistor (TR 2 ) formed on the GIP area (G/A) is formed with the same structure. 
         [0056]    In particular, though it is illustrated an example in the drawing that each thin film transistor (TR 1 , TR 2 ) has a polysilicon semiconductor layer  103  with a top gate type, a bottom gate type may be also applicable to the driving thin film transistor (TR 1 ). 
         [0057]    When the thin film transistors (TR 1 , TR 2 ) are configured with a bottom gate type, the layer structure may include a semiconductor layer separated from an active layer with a gate electrode/a gate insulating layer/with pure amorphous silicon and made of an ohmic contact layer with impurity amorphous silicon, and a source electrode and a drain electrode separated from each other. 
         [0058]    Furthermore, a planarization layer  115  having a drain contact hole (not shown) for exposing the drain electrode  113   b  is layered on the driving thin film transistor (TR 1 ). Either one of an insulating material, for example, silicon oxide (SiO 2 ) or silicon nitride (SiNx) which is an inorganic insulating material, or an organic insulating material including photo acryl may be used for the planarization layer  115 . 
         [0059]    In addition, a first electrode  121  brought into contact with the drain electrode  113   c  of the driving thin film transistor (TR 1 ) through the drain contact hole (not shown) to have a separated shape for each pixel (PX) may be formed on the planarization layer  115 . 
         [0060]    In addition, a bank  123  made of an insulating material, particularly, benzo-cyclo-butene (BCB), polyimide or photo acryl, is formed on the first electrode  121  up to the boundary of each pixel (PX) and non-active area (N/A). The bank  123  is formed in a shape surrounding each pixel (PX) to be overlapped with an edge of the first electrode  121 , and formed in a lattice shape having a plurality of opening portions as a whole on the active area (A/A). 
         [0061]    An organic light emitting layer  125  configured with an organic light emitting pattern (not shown) that emits red, green and blue colors, respectively, on the first electrode  121  within each pixel (PX) surrounded by the bank  123 . The organic light emitting layer  125  may be configured with a single layer made of an organic light emitting material or configured with a multi-layer having a hole injection layer, a hole transporting layer, an emitting material layer, an electron transporting layer, and an electron injection layer. 
         [0062]    A second electrode  127  is formed on an entire surface of the active area (A/A) on the organic light emitting layer  125  and bank  123 . Here, the first electrode  121  and second electrode  127  and an organic light emitting layer  125  interposed therebetween constitute one organic light emitting diode. 
         [0063]    In describing the operation of an organic light emitting diode having the foregoing structure, as a predetermined gradation value reflected voltage is applied to the first electrode  121  and second electrode  127 , a hole injected from the first electrode  121  and an electron provided from the second electrode  127  are transported to the organic light emitting layer  125  to form an exciton. When an excited state returns to a ground state, the exciton emits light as luminous energy, and the emitted light exits to the outside through the transparent second electrode  127 , and thus the flexible display panel  100  implements an arbitrary image. 
         [0064]    On the other hand, a first passivation layer  129  made of an insulating material, particularly, silicon oxide (SiO 2 ) or silicon nitride (SiNx), which is an inorganic insulating material, is formed on the active area (A/A) of the substrate including the second electrode  127 . The first passivation layer  129  is formed since moisture infiltration into the organic light emitting layer  125  cannot be blocked only with the second electrode  127 , and thus the first passivation layer  129  performing a protective role is formed on the second electrode  127  to minimize moisture infiltration into the organic light emitting layer  125 . 
         [0065]    Furthermore, the GIP thin film transistor (TR 2 ) on the GIP area (G/A) has a similar layer structure to that of the driving thin film transistor (TR 1 ) on the active area (A/A) from the semiconductor layer  103  to the first passivation layer  129 , but has a structure in which the first and the second electrode  121 ,  127  and organic light emitting layer  125  are omitted. 
         [0066]    On the contrary, the bending area (B/A) has a difference in that the gate insulating layer  105 , interlayer insulating layer  109 , planarization layer  115  and the like excluding the auxiliary line  120  as well as the foregoing thin film transistors (TR 1 , TR 2 ) are not formed thereon. 
         [0067]    On the other hand, an organic layer  141  made of a polymeric organic material such as a polymer is formed on the first passivation layer  129  of the active area (A/A). Here, an olefin-based polymer (polyethylene, polypropylene), polyethylene terephthalate (PET), epoxy resin, fluororesin, polysiloxane, and the like may be used for a polymer layer constituting an organic layer  131 . 
         [0068]    Furthermore, in order to block moisture from being infiltrated through the organic layer  141 , a second passivation layer  143  made of an insulating material, for example, silicon oxide (SiO 2 ) or silicon nitride (SiNx), which is an inorganic insulating material, is formed on the active area (A/A) including the organic layer  141 . 
         [0069]    In addition, a barrier film  147  is positioned in a facing manner for the encapsulation of the organic light emitting diode on an entire surface of the substrate including the second passivation layer  143 , and an adhesive  145  made of any one of a frit, an organic insulating material, and a polymeric material having transparent and adhesive characteristics is completely adhered to the substrate  101  and barrier film  147  with no air layer between the second passivation layer  143  and barrier film  147 . 
         [0070]    A polarizing film  160  is adhered to an upper portion of the barrier film  147 . The polarizing film  160  is completely closely adhered to the barrier film  147  with no gap to perform the role of preventing image quality from being deteriorated by the reflection of light incident from the outside to the organic light emitting display device. 
         [0071]    On the other hand, a protective layer  150  is formed on the auxiliary line  120  over the bending area (B/A). The protective layer  150  is provided to minimize the damage of the auxiliary line  120  due to the bending of the flexible display panel  100  as well as perform the role of preventing moisture infiltration, and a material having flexible characteristics is used for the protective layer  150 . 
         [0072]    In particular, when the bending area (B/A) is warped and the GIP area (G/A) is positioned on a rear surface of the flexible display panel  100  according to a narrow bezel structure, the protective layer  150  performs the role of minimizing an attractive force or tension applied to the protective layer  150  in consideration of the thickness and Young&#39;s modulus. To this end, the protective layer  150  may be formed of the same material with the same thickness as that of the substrate  101 . 
         [0073]    The protective layer  150  is formed to expose the auxiliary line  120  during the deposition of the foregoing gate insulating layer  105 , interlayer insulating layer  109 , planarization layer  115  and the like subsequent to the formation of the auxiliary line  120 , and formed prior to the adhesion of the barrier film  147  or polarizing film  160 . 
         [0074]    On the other hand, the flexible display panel  100  is warped in a gravitational direction due to the flexibility of the substrate  101  during the fabrication process of the display device, and thus has a disadvantage of being difficult to be applicable to the process. In the prior art, in order to solve the foregoing problem, a polyethylene terephthalate (PET) film is adhered over the entire rear surface area of the flexible display panel  100  to facilitate the fabrication process of the display device, but it also acts as a factor of disturbing the bending process. Accordingly, according to an embodiment of the present invention, the PET film  190  is adhered only to a portion corresponding to the active area (A/A) on a rear surface of the flexible display panel  100 . 
         [0075]    Hereinafter, an assembled form according to the bending structure of a flexible display panel according to an embodiment of the present invention will be described with reference to the accompanying drawings. 
         [0076]      FIG. 5A  is a view illustrating an example in which a flexible display panel according to an embodiment of the present invention is fixed in a bending structure, and  FIG. 5B  is a view illustrating the cross section of a portion taken along line V-V′ in  FIG. 5A . 
         [0077]    As illustrated in  FIGS. 5A and 5B , in a flexible display panel  100  according to the present invention, a pixel circuit layer  110  including a plurality of signal lines and transistors is formed in the active area (A/A) on the plastic substrate  101 , and a GIP circuit layer  111  including a gate driving circuit is formed on the non-active area (N/A) in a similar structure to that of the pixel circuit layer  110 . A PET film  180  for preventing the substrate  101  from being warped during the fabrication process is adhered to the active area (A/A) on a rear surface of the substrate  101 . Furthermore, a barrier film  140  for protecting the pixel circuit layer  110  and a polarizing film  160  for compensating optical characteristics are adhered to an upper portion of the pixel circuit layer  110 . 
         [0078]    The pixel circuit layer  110  may further include an organic light emitting layer for displaying an image as well as a thin film transistor contrary to the GIP circuit layer  111 . 
         [0079]    The substrate  101  is adhered to a mechanical structure  190  on a rear surface thereof through a predetermined adhesive  195 , and a side end of the mechanical structure  190  may have a circular structure such that a side end of the substrate  101  is warped while forming a predetermined radius. 
         [0080]    Furthermore, the bending area (B/A) being warped in a rear surface direction as the substrate  101  is adhered onto the mechanical structure  190  excluding the GIP area (G/A) is defined on the non-active area (N/A), and the auxiliary line  120  for electrically connecting the pixel circuit layer  110  to GIP circuit layer  111  is formed on the bending area (B/A). Furthermore, the protective layer  150  for minimizing a force acting on the auxiliary line  120  according to the warpage as well as preventing the auxiliary line  120  from being exposed to the outside to be damaged is formed on the auxiliary line  120 . Here, the thickness and material quality of the protective layer  150  are determined by the substrate  101  and auxiliary line  120 . 
         [0081]    Accordingly, in the flexible display panel  100  mounted on the mechanical structure  190 , the gate driving circuit is positioned on a rear surface of the mechanical structure  190  and the width of both the left and right bezel portions thereof is reduced when viewed from the front surface, thereby implementing a narrow bezel (N/B). 
         [0082]    On the other hand, the foregoing embodiment has a structure in which only both the left and right bezel portions of the flexible display panel  100  are bent, and a flexible display panel according to another embodiment of the present invention will be described with reference to the accompanying drawings. 
         [0083]      FIG. 6A  is a view for explaining a method of processing a flexible display panel according to another embodiment of the present invention, and  FIG. 6B  is a view illustrating a display device structure subsequent to the bending of the processed flexible display panel according to an embodiment of the present invention. 
         [0084]    Referring to  FIG. 6A , a flexible display device  200  according to the present invention is defined with an active area (A/A) in which an actual image is implemented on a substrate  201  and a non-active area (N/A) surrounding the active area (A/A), and a pixel area defined by a plurality of gate lines and data lines is formed in the active area (A/A), and each pixel area is formed with a thin film transistor. 
         [0085]    Furthermore, two gate driving circuits  230  connected to gate lines are embedded therein in a GIP structure at the left and right side ends of the non-active area (N/A) of the flexible display panel  200 . A data driving circuit  240  is electrically connected to a substrate pad  246  formed at one side end of the display panel  200 . Furthermore, a polarizing film  260  for compensating the optical characteristics of the display panel  200  is adhered onto a front surface of the active area (A/A). In particular, an auxiliary line and a protective layer  250  thereon are formed between the active area (A/A) and the gate driving circuit  230 . 
         [0086]    When at least one portion of each side end is bent to implement a narrow bezel for the flexible display panel  200  with the foregoing structure, there is a limit in that it is difficult to bend the left and right side ends thereof due to an interference of the folded portion when the top and bottom side ends thereof are bent, and also difficult to bend the top and bottom side ends thereof when the left and right side ends thereof are bent. 
         [0087]    In order to address these issues, according to another embodiment of the present invention, each corner region (a-d) illustrated in  FIG. 6A  is cut to minimize a mutual interference during the bending of four side ends. In other words, each corner region (a-d) is removed through a predetermined chamfering process prior to bending the flexible display panel  200 , and then the top, bottom, left and right side ends of the flexible display panel  200  are bent to implement a narrow bezel (N/B) for all side ends thereof. 
         [0088]    Here, though not shown in the drawing, a conventional layer structure is omitted between the active area (A/A) and the data driving circuit  240  to apply a structure forming an auxiliary line and a protective layer thereon, thereby minimizing the damage of the signal line and layer structure due to bending between the active area (A/A) and the data driving circuit  240 . 
         [0089]    Although many subject matters have been specifically disclosed in the foregoing description, they should be construed as an illustration of preferred embodiments rather than a limitation to the scope of invention. Consequently, the invention should not be determined by the embodiments disclosed herein but should be determined by the claims and the equivalents thereof.