Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of Korean Patent Application No. 10-2015-0108716 filed in the Republic of Korea on Jul. 31, 2015, which is hereby incorporated by reference. 
       BACKGROUND 
     Field of Technology 
       [0002]    The present disclosure relates to an organic light emitting display (OLED) device and more particularly to a foldable OLED device that prevents being damaged by moisture. 
       Discussion of the Related Art 
       [0003]    As information technology and mobile communication technology have been developed, a display device capable of displaying a visual image has also been developed. Flat panel display devices, such as a liquid crystal display (LCD) device and an OLED device, are developed and used. 
         [0004]    Among these flat panel display devices, since the OLED device has advantages in response time, contrast ratio, viewing angle, power consumption, and so on, the OLED device is widely developed. 
         [0005]    An emitting diode including an organic emitting layer is susceptible to damage from moisture. To prevent moisture penetration into the emitting diode and protect the emitting diode from external impacts, an encapsulation substrate of glass is attached onto the emitting diode. 
         [0006]    Recently, foldable or bendable display devices (hereinafter “foldable display device”) have been introduced. 
         [0007]    In the foldable OLED device, an encapsulation film including an inorganic layer and an organic layer is used instead of the encapsulation substrate. Namely, by using the encapsulation film for preventing moisture penetration into the emitting diode and to protect the emitting diode, the display device has a foldable property. 
         [0008]    However, when the foldable OLED device is operated under a condition of high temperature and high humidity, the emitting diode is damaged resulting in problems in display quality and a lifetime of the foldable OLED device. 
       SUMMARY 
       [0009]    Accordingly, the present invention is directed to a foldable OLED device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
         [0010]    An object of the present invention is to provide a foldable OLED device being capable of preventing damage by moisture. 
         [0011]    Another object of the present invention is to provide a foldable OLED device having advantages in production costs. 
         [0012]    Another object of the present invention is to provide a foldable OLED device having a narrow bezel. 
         [0013]    Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
         [0014]    To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, a foldable organic light emitting display (OLED) device comprises a substrate including a display region and a non-display region, the non-display region located at a periphery of the display region; an emitting diode in the display region; and an encapsulation film covering both the emitting diode and an entirety of the display region, and the encapsulation film covering a part of the non-display region without covering at least another part of the non-display region. 
         [0015]    In another aspect, a foldable organic light emitting display (OLED) device comprises a substrate including a folding region along a first direction in which the foldable device is foldable; an emitting diode on substrate; and an encapsulation film including a first inorganic layer covering the emitting diode, an organic layer on the first inorganic layer and a second inorganic layer on the organic layer, wherein in the first direction, the second inorganic layer is wider than the first inorganic layer and covers side surfaces of the first inorganic layer, and in a second direction that is perpendicular to the first direction, a width of the second inorganic layer is substantially the same as a width of the first inorganic layer. 
         [0016]    In another aspect, a foldable organic light emitting display (OLED) device comprises a flexible substrate including a display region and a non-display region located at a periphery of the display region, the flexible substrate folded across a folding region that is along a first direction of the foldable OLED device; an emitting diode in the display region; and an encapsulation film covering both the emitting diode and an entirety of the display region, and the encapsulation film covering a part of the non-display region without covering at least another part of the non-display region. 
         [0017]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    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. 
           [0019]      FIG. 1  is a schematic cross-sectional view illustrating a scribing process of a foldable OLED device. 
           [0020]      FIG. 2  is a schematic cross-sectional view illustrating damages in an encapsulation film of a foldable OLED device. 
           [0021]      FIG. 3A  is a schematic plane view illustrating a foldable OLED device according to one embodiment of the present disclosure. 
           [0022]      FIG. 3B  is a view of the foldable OLED device folded across the folding region according to one embodiment of the present disclosure. 
           [0023]      FIGS. 4A and 4B  are schematic cross-sectional views illustrating a foldable OLED device according to a first embodiment of the present disclosure. 
           [0024]      FIG. 5  is a schematic cross-sectional view illustrating a pixel structure of a foldable OLED device of the present disclosure. 
           [0025]      FIGS. 6A and 6B  are schematic cross-sectional views illustrating a foldable OLED device according to a second embodiment of the present disclosure. 
           [0026]      FIGS. 7A and 7B  are schematic cross-sectional views illustrating a foldable OLED device according to a third embodiment of the present disclosure. 
           [0027]      FIGS. 8A to 8D  are schematic views illustrating a foldable OLED device according to a fourth embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Reference will now be made in detail to the preferred embodiments, examples of which are illustrated in the accompanying drawings. 
         [0029]      FIG. 1  is a schematic cross-sectional view illustrating a scribing process of a foldable OLED device, and  FIG. 2  is a schematic cross-sectional view illustrating damages in an encapsulation film of a foldable OLED device. 
         [0030]    As shown in  FIGS. 1 and 2 , an OLED device  1  includes a flexible substrate  10 , an emitting diode D and an encapsulating film  20  covering the emitting diode D. 
         [0031]    The flexible substrate  10  may include polymer such as polyimide, and the emitting diode D is formed on or over the flexible substrate  10 . 
         [0032]    Although not shown, the emitting diode D includes first and second electrodes facing each other and an organic emitting layer between the first and second electrodes. In addition, on the flexible substrate  10 , a switching thin film transistor (TFT) as a switching element and a driving TFT as a driving element are formed, and the first electrode of the emitting diode D is connected to the driving TFT. 
         [0033]    The encapsulating film  20  covers the emitting diode D to prevent damage to the emitting diode D under conditions of high temperature and high humidity. 
         [0034]    In the encapsulation film  20 , an inorganic layer and an organic layer are alternately stacked. For example, the encapsulation film  20  may have a triple-layered structure including a first inorganic layer  22  on the emitting diode D, an organic layer  24  on the first inorganic layer  22  and a second inorganic layer  26  on the organic layer  24 . 
         [0035]    A plurality of cells are formed on a mother substrate, and each cell is separated by a scribing process to provide the OLED device  1 . 
         [0036]    Namely, a plurality of emitting diodes D are formed in each cell, and the encapsulation film  20  is formed to cover an entire surface of the mother substrate. Then, the scribing process is performed to separate each cell. 
         [0037]    Since the scribing process is performed onto the encapsulation film  20 , the encapsulation film  20  is damaged. Namely, cracks may be generated in the first inorganic layer  22  and the second inorganic layer  26 , and moisture may penetrate into the emitting diode D through the cracks as shown in  FIG. 2 . As a result, the emitting diode D may be damaged. 
         [0038]    In the foldable OLED device, stress by folding operation is concentrated into the encapsulation film  20  in a folding region. Accordingly, when damages, such as cracks, are generated in the encapsulation film  20  by the scribing process, the cracks can grow due to the folding operation causing further damage to the emitting diode D. 
         [0039]      FIG. 3A  is a schematic plane view illustrating a foldable OLED device according to one embodiment of the present disclosure. 
         [0040]    As shown in  FIG. 3 , an OLED device  100  is a foldable OLED device capable of being folded along a folding region FR. For example, the folding region FR is defined along a direction of a minor axis of the foldable OLED device  100 . Alternatively, the folding region FR may be defined along a direction of a major axis of the foldable OLED device  100 . 
         [0041]    When the folding region FR is defined along the direction of the minor axis of the foldable OLED device  100 , a pad region (not shown) is defined in at least one end along the direction of the major axis. 
         [0042]    In the foldable OLED device  100  of the present disclosure, a plurality of pixel regions P are defined on a flexible substrate  110 , and an emitting diode (not shown) is formed in a display region including the plurality of pixel regions P. In addition, an encapsulating film covering the emitting diode is formed. 
         [0043]    In the folding region FR, the encapsulation film has a width smaller than the flexible substrate  110 . Namely, in the direction of the minor axis, both ends of the encapsulation film are positioned inside both ends of the flexible substrate  110 . In addition, the end of the encapsulation film in the folding region and the end of the encapsulation film along a direction, which crosses the folding region, may have a symmetric structure or an asymmetric structure. 
         [0044]    Due to the encapsulation film, damages on the encapsulation film from the scribing process and the folding operation are prevented such that the problem of the display quality and the lifetime in the foldable OLED device  100  is overcome.  FIG. 3B  is a view of the foldable OLED device  100  folded across the folding region FR shown in  FIG. 3A . 
         [0045]      FIGS. 4A and 4B  are schematic cross-sectional views illustrating a foldable OLED device according to a first embodiment of the present disclosure, and  FIG. 5  is a schematic cross-sectional view illustrating a pixel structure of a foldable OLED device of the present disclosure.  FIG. 4B  is a cross-sectional view taken along the line A-A′ in  FIG. 3 , and  FIG. 5  is a cross-sectional view taken along the line B-B′ in  FIG. 3 . 
         [0046]    As shown in  FIG. 4A , an emitting diode D is formed to correspond to a display region of each cell in a mother substrate (not shown), and an encapsulation film  170  is formed to cover the emitting diode D and correspond to the display region and a part of a non-display region at peripheries of the display region. 
         [0047]    Next, a scribing process is performed to separate each cell such that the flexible OLED device  100  is fabricated. 
         [0048]    Since ends of the encapsulation film  170  are positioned inside scribing lines, the scribing process is not performed to the encapsulation film  170 . Accordingly, the damages, such as cracks, are not generated in the encapsulation film  170  in the scribing process. 
         [0049]    As shown in  FIG. 4B , the flexible OLED device  100  fabricated by the above scribing process includes the flexible substrate  110 , where the display region and the non-display region are defined, the emitting diode D corresponding to the display region and disposed on or over the flexible substrate  110 , and the encapsulation film  170  covering the emitting diode D and corresponding to the display region and a part of the non-display region. 
         [0050]    Referring to  FIG. 5 , a TFT Tr, the emitting diode D, and the encapsulation film  170  are sequentially stacked on the flexible substrate  110 . 
         [0051]    For example, the flexible substrate  110  may be a polyimide substrate. Since the flexible substrate  110  is inadequate to a process of forming elements, such as the TFT Tr, the process of forming the elements is performed on the flexible substrate  110  attached to a carrier substrate (not shown) such as a glass substrate. After the process of forming the elements, the carrier substrate and the flexible substrate  110  is separated or released. 
         [0052]    The TFT Tr is formed on the flexible substrate  110 . Although not shown, a buffer layer may be formed on the flexible substrate  110 , and the TFT Tr may be formed on the buffer layer. 
         [0053]    A semiconductor layer  122  is formed on the flexible substrate  110 . The semiconductor layer  122  may include an oxide semiconductor material or polycrystalline silicon. 
         [0054]    When the semiconductor layer  122  includes the oxide semiconductor material, a light-shielding pattern (not shown) may be formed under the semiconductor layer  122 . The light to the semiconductor layer  122  is shielded or blocked by the light-shielding pattern such that thermal degradation of the semiconductor layer  122  can be prevented. On the other hand, when the semiconductor layer  122  includes polycrystalline silicon, impurities may be doped into both sides of the semiconductor layer  122 . 
         [0055]    A gate insulating layer  124  is formed on the semiconductor layer  122 . The gate insulating layer  124  may be formed of an inorganic insulating material such as silicon oxide or silicon nitride. 
         [0056]    A gate electrode  130 , which is formed of a conductive material, e.g., metal, is formed on the gate insulating layer  124 . In one embodiment, the gate electrode  130  is formed at a location corresponding to a center of the semiconductor layer  122 . 
         [0057]    In  FIG. 5 , the gate insulating layer  124  is formed on the entire surface of the flexible substrate  110 . Alternatively, the gate insulating layer  124  may be patterned to have the same shape as the gate electrode  130 . 
         [0058]    An interlayer insulating layer  132 , which is formed of an insulating material, is formed on an entire surface of the flexible substrate  110  including the gate electrode  130 . The interlayer insulating layer  132  may be formed of an inorganic insulating material, e.g., silicon oxide or silicon nitride, or an organic insulating material, e.g., benzocyclobutene or photo-acryl. 
         [0059]    The interlayer insulating layer  132  includes a first contact hole  134  and a second contact hole  136  exposing both sides of the semiconductor layer  122 . The first contact hole  134  and second contact hole  136  are positioned at both sides of the gate electrode  130  to be spaced apart from the gate electrode  130 . 
         [0060]    In  FIG. 5 , the first contact hole  134  and second contact hole  136  extend into the gate insulating layer  124 . Alternatively, when the gate insulating layer  124  is patterned to have the same shape as the gate electrode  130 , there may be no first contact hole  134  and second contact hole  136  in the gate insulating layer  124 . 
         [0061]    A source electrode  140  and a drain electrode  142 , which are formed of a conductive material, e.g., metal, are formed on the interlayer insulating layer  132 . The source electrode  140  and the drain electrode  142  are spaced apart from each other with respect to the gate electrode  130  and respectively contact both sides of the semiconductor layer  122  through the first and second contact holes  134  and  136 . 
         [0062]    The semiconductor layer  122 , the gate electrode  130 , the source electrode  140  and the drain electrode  142  constitute the TFT Tr, and the TFT Tr serves as a driving element. 
         [0063]    In  FIG. 5 , the gate electrode  130 , the source electrode  140  and the drain electrode  142  are positioned over the semiconductor layer  122 . Namely, the TFT Tr has a coplanar structure. 
         [0064]    Alternatively, in the TFT Tr, the gate electrode may be positioned under the semiconductor layer, and the source and drain electrodes may be positioned over the semiconductor layer such that the TFT Tr may have an inverted staggered structure. In this instance, the semiconductor layer may include amorphous silicon. 
         [0065]    Although not shown, a gate line and a data line are disposed on or over the flexible substrate  110  and cross each other to define a pixel region. In addition, a switching element, which is electrically connected to the gate line and the data line, may be disposed on the flexible substrate  110 . The switching element is electrically connected to the TFT Tr as the driving element. 
         [0066]    In addition, a power line, which is parallel to and spaced apart from the gate line or the data line, may be formed on or over the flexible substrate  110 . Moreover, a storage capacitor for maintaining a voltage of the gate electrode  130  of the TFT Tr during one frame, may be further formed on the flexible substrate  110 . 
         [0067]    A passivation layer  150 , which includes a drain contact hole  152  exposing the drain electrode  142  of the TFT Tr, is formed to cover the TFT Tr. 
         [0068]    A first electrode  160 , which is connected to the drain electrode  142  of the TFT Tr through the drain contact hole  152 , is separately formed in each pixel region. The first electrode  160  may be an anode and may be formed a conductive material having a relatively high work function. For example, the first electrode  160  may be formed of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO). 
         [0069]    When the flexible OLED device  100  is operated in a top-emission type, a reflection electrode or a reflection layer may be formed under the first electrode  160 . For example, the reflection electrode or the reflection layer may be formed of aluminum-paladium-copper (APC) alloy. 
         [0070]    A bank layer  166 , which covers edges of the first electrode  160 , is formed on the passivation layer  150 . A center of the first electrode  160  in the pixel region is exposed through an opening of the bank layer  166 . 
         [0071]    An organic emitting layer  162  is formed on the first electrode  160 . The organic emitting layer  162  may have a single-layered structure of an emitting material layer formed of an emitting material. Alternatively, to improve emitting efficiency, the organic emitting layer  162  may have a multi-layered structure including a hole injection layer, a hole transporting layer, the emitting material layer, an electron transporting layer and an electron injection layer sequentially stacked on the first electrode  160 . 
         [0072]    A second electrode  164  is formed over the flexible substrate  110  including the organic emitting layer  162 . The second electrode  164  is positioned at an entire surface of the display area. The second electrode  164  may be a cathode and may be formed of a conductive material having a relatively low work function. For example, the second electrode  164  may be formed of aluminum (Al), magnesium (Mg) or Al—Mg alloy. 
         [0073]    The first electrode  160 , the organic emitting layer  162  and the second electrode  164  constitute the light emitting diode D. 
         [0074]    An encapsulation film  170  is formed on the light emitting diode D to prevent moisture penetration into the light emitting diode D. 
         [0075]    The encapsulation film  170  has a width smaller than the flexible substrate  110 , and the ends of the encapsulation film  170  are positioned on the flexible substrate  110 . 
         [0076]    Namely, as shown in  FIG. 4A , since the mother substrate including the encapsulation film  170 , which has a smaller area than the cell, is scribed, the width of the encapsulation film  170  is smaller than that of the flexible substrate  110  such that the ends of the encapsulation film  170  are positioned inside the ends of the flexible substrate  110 . As a result, the damages, such as cracks, in the encapsulation film by the scribing process are prevented. 
         [0077]    In addition, since there is no encapsulation film  170  in the end of the folding region FR, the folding stress generated in the folding operation is not concentrated in the encapsulation film  170 . Accordingly, the damages on the encapsulation film  170  by the folding operation is minimized or prevented. 
         [0078]    In other words, in the ends of the folding region FR, the encapsulation film  170  is removed such that one of the passivation layer  150  (of  FIG. 5 ), the interlayer insulating layer  132  (of  FIG. 5 ), the gate insulating layer  124  (of  FIG. 5 ) and the flexible substrate  110  is exposed and the ends of the encapsulation film  170  are disposed on the one of the passivation layer  150 , the interlayer insulating layer  132 , the gate insulating layer  124  and the flexible substrate  110 . 
         [0079]    On the other hand, to prevent the damages on the passivation layer  150 , the interlayer insulating layer  132  or the gate insulating layer  124  by the scribing process and moisture penetration into the display region, all of the passivation layer  150 , the interlayer insulating layer  132  and the gate insulating layer  124  may be removed in the ends of the folding region FR such that the encapsulation film  170  may contact the flexible substrate  110  in the ends of the folding region FR. 
         [0080]    The encapsulation film  170  includes a first inorganic layer  172 , an organic layer  174  and a second inorganic layer  176 . However, it is not limited thereto. 
         [0081]    For example, the encapsulation film  170  may further include an organic layer on the second inorganic layer  176  to have a quadruple-layered structure or may further include an organic layer and an inorganic layer on the second inorganic layer  176  to have a five-layered structure. 
         [0082]    The first and second inorganic layers  172  and  176  have the same plane area and completely overlap each other. The organic layer  174  is positioned between the first and second inorganic layers  172  and  176 . The organic layer  174  has a plane area smaller than the first and second inorganic layers  172  and  176  and completely overlaps the first and second inorganic layers  172  and  176 . Namely, the organic layer  174  is completely covered and protected by the second inorganic layer  176  such that moisture penetration through the organic layer  174  is prevented. 
         [0083]    For example, when the organic layer  174  has the same plane area as or larger area than the second inorganic layer  176 , a side surface of the organic layer  174  is exposed and moisture penetration may be generated through the side surface of the organic layer  174 . However, in the present disclosure, since the organic layer  174  is completely covered and protected by the second inorganic layer  176 , moisture penetration through the organic layer  174  is prevented. 
         [0084]    Each of the first inorganic layer  172  and second inorganic layer  176  may be formed of silicon oxide or silicon nitride, and the organic layer  174  may be formed of an epoxy compound or an acryl compound. 
         [0085]    Although not shown, a barrier film may be attached to the encapsulation film  170 , and a polarization plate for reducing an ambient light reflection may be attached to the barrier film. For example, the polarization plate may be a circular polarization plate. 
         [0086]    As mentioned above, in the flexible OLED device  100  of the present disclosure, since the encapsulation film  170  is positioned inside the flexible substrate  110 , the damages on the encapsulation film  170  by the scribing process are prevented. 
         [0087]    In addition, since the ends of the encapsulation film  170  in the folding region FR are positioned inside the ends of the flexible substrate  110 , the folding stress is not concentrated in the ends of the encapsulation film  170 . 
         [0088]    Accordingly, the decrease of the display quality and the lifetime in the flexible OLED device  100  generated by the damages on the elements, e.g., the emitting diode D, by the moisture penetration is minimized or prevented. 
         [0089]      FIGS. 6A and 6B  are schematic cross-sectional views illustrating a foldable OLED device according to a second embodiment of the present disclosure.  FIG. 6A  is a cross-sectional view taken along the line A-A′ in  FIG. 3 , and  FIG. 6B  is a cross-sectional view taken along the line C-C′ in  FIG. 3 . 
         [0090]    As shown in  FIGS. 6A and 6B , a flexible OLED device  200  according to the second embodiment of the present disclosure includes the flexible substrate  210 , where the display region and the non-display region are defined, the emitting diode D corresponding to the display region and disposed on or over the flexible substrate  210 , and the encapsulation film  270  covering the emitting diode D and corresponding to the display region and a part of the non-display region. 
         [0091]    For example, the flexible substrate  210  may be a polyimide substrate. The TFT Tr (of  FIG. 5 ), the emitting diode D and the encapsulation film  270  are formed on or over the flexible substrate  210 . 
         [0092]    As illustrated with  FIG. 5 , the TFT Tr may include the semiconductor layer  122 , the gate electrode  130 , the source electrode  140  and the drain electrode  142 , and the emitting diode D may include the first electrode  160 , which is connected to the drain electrode  142 , the second electrode  164 , which faces the first electrode  160 , and the organic emitting layer  162  between the first and second electrodes  160  and  164 . 
         [0093]    The encapsulation film  270  covers the emitting diode D and has an area smaller than the flexible substrate  210 . Namely, the ends of the encapsulation film  270  are positioned inside the ends of the flexible substrate  210 . 
         [0094]    In the ends of the folding region FR, the encapsulation film  270  is removed such that one of the passivation layer  150  (of  FIG. 5 ), the interlayer insulating layer  132  (of  FIG. 5 ), the gate insulating layer  124  (of  FIG. 5 ) and the flexible substrate  210  is exposed and the ends of the encapsulation film  270  are disposed on the one of the passivation layer  150 , the interlayer insulating layer  132 , the gate insulating layer  124  and the flexible substrate  210 . 
         [0095]    On the other hand, to prevent the damages on the passivation layer  150 , the interlayer insulating layer  132 , or the gate insulating layer  124  by the scribing process and moisture penetration into the display region, all of the passivation layer  150 , the interlayer insulating layer  132  and the gate insulating layer  124  may be removed in the ends of the folding region FR such that the encapsulation film  270  may contact the flexible substrate  210  in the ends of the folding region FR. 
         [0096]    The encapsulation film  270  includes a first inorganic layer  272 , an organic layer  274  and a second inorganic layer  276 . However, it is not limited thereto. 
         [0097]    For example, the encapsulation film  270  may further include an organic layer and an inorganic layer on the second inorganic layer  276  to have a five-layered structure. 
         [0098]    The first and second inorganic layers  272  and  276  have the same plane area and completely overlap each other. The organic layer  274  is positioned between the first and second inorganic layers  272  and  276 . The organic layer  274  has a plane area smaller than the first inorganic layer  272  and second inorganic layer  276  and completely overlaps the first inorganic layer  272  and second inorganic layer  276 . Namely, the organic layer  274  is completely covered and protected by the second inorganic layer  276  such that moisture penetration through the organic layer  274  is prevented. 
         [0099]    For example, when the organic layer  274  has the same plane area as or larger area than the second inorganic layer  276 , a side surface of the organic layer  274  is exposed and moisture penetration may be generated through the side surface of the organic layer  274 . However, in the present disclosure, since the organic layer  274  is completely covered and protected by the second inorganic layer  276 , moisture penetration through the organic layer  274  is prevented. 
         [0100]    Each of the first inorganic layer  272  and second inorganic layer may be formed of silicon oxide or silicon nitride, and the organic layer  274  may be formed of an epoxy compound or an acryl compound. 
         [0101]    As shown in  FIG. 6A , in the folding region FR, the end of the encapsulation film  270  has a first distance D 1  from the flexible substrate  210 . 
         [0102]    On the other hand, as shown in  FIG. 6B , in a side along a first direction, which is perpendicular to an extension direction (i.e., a second direction) of the folding region FR, the end of the encapsulation film  270  has a second distance D 2 , which is smaller than the first distance D 1 , from the flexible substrate  210 . 
         [0103]    Namely, the encapsulation film  270  has an asymmetric shape such that a distance between the end of the encapsulation film  270  and the end of the flexible substrate  210  is varied with respect to a direction. 
         [0104]    In other words, in the second direction, where the ends of the folding region FR, in which the folding stress is generated, are disposed, the end of the encapsulation film  270  is positioned to be far away from the end of the flexible substrate  210 , the damage on the encapsulation film  270  by the folding stress is minimized. 
         [0105]    In addition, in the first direction, which may be perpendicular to the extension direction of the folding region FR, since the end of the encapsulation film  270  is disposed to be relatively close to the end of the flexible substrate  210 , efficiency of the mother substrate is increased. Namely, since there is no folding stress in the end of the line C-C′ in  FIG. 3 , there is no damage in the encapsulation film  270  even when the end of the encapsulation film  270  has the second distance D 2 , which is a relatively small, from the end of the flexible substrate  210 . In this instance, since the end of the flexible substrate  210  and the end of the encapsulation film  270  is closer, the number of the cells in the direction of the line C-C′ can be increased. 
         [0106]    Moreover, as explained in  FIG. 4A , the encapsulation film  270  has a patterned shape, i.e., an island shape, in each cell of the mother substrate, the damage on the encapsulation film  270  by the scribing process is prevented. 
         [0107]    Accordingly, the damage on the emitting diode D by the moisture penetration is prevented, and the production costs of flexible OLED device are reduced. 
         [0108]      FIGS. 7A and 7B  are schematic cross-sectional views illustrating a foldable OLED device according to a third embodiment of the present disclosure.  FIG. 7A  is a cross-sectional view taken along the line A-A′ in  FIG. 3 , and  FIG. 7B  is a cross-sectional view taken along the line C-C′ in  FIG. 3 . 
         [0109]    As shown in  FIGS. 7A and 7B , a flexible OLED device  300  according to the third embodiment of the present disclosure includes the flexible substrate  310 , where the display region and the non-display region are defined, the emitting diode D corresponding to the display region and disposed on or over the flexible substrate  310 , and the encapsulation film  370  covering the emitting diode D and corresponding to the display region and a part of the non-display region. 
         [0110]    For example, the flexible substrate  310  may be a polyimide substrate. The TFT Tr (of  FIG. 5 ), the emitting diode D and the encapsulation film  370  are formed on or over the flexible substrate  310 . 
         [0111]    As illustrated with  FIG. 5 , the TFT Tr may include the semiconductor layer  122 , the gate electrode  130 , the source electrode  140  and the drain electrode  142 , and the emitting diode D may include the first electrode  160 , which is connected to the drain electrode  142 , the second electrode  164 , which faces the first electrode  160 , and the organic emitting layer  162  between the first and second electrodes  160  and  164 . 
         [0112]    The encapsulation film  370  covers the emitting diode D and has an area smaller than the flexible substrate  310 . Namely, the ends of the encapsulation film  370  are positioned inside the ends of the flexible substrate  310 . 
         [0113]    In the ends of the folding region FR, the encapsulation film  370  is removed such that one of the passivation layer  150  (of  FIG. 5 ), the interlayer insulating layer  132  (of  FIG. 5 ), the gate insulating layer  124  (of  FIG. 5 ) and the flexible substrate  310  is exposed and the ends of the encapsulation film  370  are disposed on the one of the passivation layer  150 , the interlayer insulating layer  132 , the gate insulating layer  124  and the flexible substrate  310 . 
         [0114]    On the other hand, to prevent the damages on the passivation layer  150 , the interlayer insulating layer  132  or the gate insulating layer  124  by the scribing process and moisture penetration into the display region, all of the passivation layer  150 , the interlayer insulating layer  132  and the gate insulating layer  124  may be removed in the ends of the folding region FR such that the encapsulation film  370  may contact the flexible substrate  310  in the ends of the folding region FR. 
         [0115]    The encapsulation film  370  includes a first inorganic layer  372 , an organic layer  374  and a second inorganic layer  376 . However, it is not limited thereto. 
         [0116]    For example, the encapsulation film  370  may further include an organic layer and an inorganic layer on the second inorganic layer  376  to have a five-layered structure. 
         [0117]    The organic layer  374  is positioned between the first inorganic layer  372  and second inorganic layer  376 . The organic layer  374  has a plane area smaller than the first and second inorganic layers  372  and  376  and completely overlaps the first and second inorganic layers  372  and  376 . Namely, the organic layer  374  is completely covered and protected by the second inorganic layer  376  such that moisture penetration through the organic layer  374  is prevented. 
         [0118]    For example, when the organic layer  374  has the same plane area as or larger area than the second inorganic layer  376 , a side surface of the organic layer  374  is exposed and moisture penetration may be generated through the side surface of the organic layer  374 . However, in the present disclosure, since the organic layer  374  is completely covered and protected by the second inorganic layer  376 , moisture penetration through the organic layer  374  is prevented. 
         [0119]    Each of the first and second inorganic layers  372  and  376  may be formed of silicon oxide or silicon nitride, and the organic layer  374  may be formed of an epoxy compound or an acryl compound. 
         [0120]    As shown in  FIG. 7A , in the folding region FR, the end of the encapsulation film  370  has a first distance D 1  from the flexible substrate  310 . 
         [0121]    On the other hand, as shown in  FIG. 7B , in a side along a direction, which is perpendicular to an extension direction of the folding region FR, the end of the encapsulation film  370  has a second distance D 2 , which is smaller than the first distance D 1 , from the flexible substrate  310 . 
         [0122]    Namely, the encapsulation film  370  has an asymmetric shape such that a distance between the end of the encapsulation film  370  and the end of the flexible substrate  310  is varied with respect to a direction. 
         [0123]    In other words, in a direction, where the ends of the folding region FR, in which the folding stress is generated, are disposed, the end of the encapsulation film  370  is positioned to be far away from the end of the flexible substrate  310 , the damage on the encapsulation film  370  by the folding stress is minimized. 
         [0124]    In addition, in a direction, which may be perpendicular to the extension direction of the folding region FR, since the end of the encapsulation film  370  is disposed to be relatively close to the end of the flexible substrate  310 , efficiency of the mother substrate is increased. Namely, since there is no folding stress in the end of the line C-C′ in  FIG. 3 , there is no damage in the encapsulation film  370  even when the end of the encapsulation film  370  has the second distance D 2 , which is a relatively small, from the end of the flexible substrate  310 . In this instance, since the end of the flexible substrate  310  and the end of the encapsulation film  370  is closer, the number of the cells in the direction of the line C-C′ can be increased. 
         [0125]    Moreover, as shown in  FIG. 7A , in a first direction, the second inorganic layer  376  covers a side surface of the first inorganic layer  372 . Namely, in the first direction, the second inorganic layer  376  has a width larger than the first inorganic layer  372 , and an end of the second inorganic layer  376  contacts an upper surface of the flexible substrate  310 . Accordingly, even though the folding stress is concentrated into the encapsulation film  370 , the first inorganic layer  372 , which is a final-protection element for the emitting diode D, is covered with the second inorganic layer  376  such that the damage on the emitting diode D by moisture penetration can be minimized. 
         [0126]    On the other hand, as shown in  FIG. 7B , in a second direction, the first and second inorganic layers  272  and  276  have the same width and completely overlap each other. To protect the emitting diode D, the first inorganic layer  372  should have a width being larger than a pre-determined width. In the present invention, since the second inorganic layer  376  in the second direction, where the folding stress is not generated, has the same width as the first inorganic layer  372 , an area increase of the non-display region in the second direction can be prevented. 
         [0127]    Accordingly, the damage on the emitting diode D by the moisture penetration is prevented, the production costs of the flexible OLED device are reduced, and the flexible OLED device having a narrow bezel is provided. 
         [0128]      FIGS. 8A to 8D  are schematic views illustrating a foldable OLED device according to a fourth embodiment of the present disclosure.  FIG. 8A  is a schematic plane view of the foldable OLED device, and  FIGS. 8B to 8D  are schematic cross-sectional views taken along the lines A-A′, C-C′ and D-D′ in  FIG. 8A . 
         [0129]    As shown in  FIGS. 8A to 8D , a flexible OLED device  400  according to the fourth embodiment of the present disclosure includes the flexible substrate  410 , where the display region and the non-display region are defined, the emitting diode D corresponding to the display region and disposed on or over the flexible substrate  410 , and the encapsulation film  470  covering the emitting diode D and corresponding to the display region and a part of the non-display region. 
         [0130]    For example, the flexible substrate  410  may be a polyimide substrate. The TFT Tr (of  FIG. 5 ), the emitting diode D and the encapsulation film  470  are formed on or over the flexible substrate  410 . 
         [0131]    As illustrated with  FIG. 5 , the TFT Tr may include the semiconductor layer  122 , the gate electrode  130 , the source electrode  140  and the drain electrode  142 , and the emitting diode D may include the first electrode  160 , which is connected to the drain electrode  142 , the second electrode  164 , which faces the first electrode  160 , and the organic emitting layer  162  between the first and second electrodes  160  and  164 . 
         [0132]    The encapsulation film  470  covers the emitting diode D and has an area smaller than the flexible substrate  410 . Namely, the ends of the encapsulation film  470  are positioned inside the ends of the flexible substrate  410 . 
         [0133]    In the ends of the folding region FR, the encapsulation film  470  is removed such that one of the passivation layer  150  (of  FIG. 5 ), the interlayer insulating layer  132  (of  FIG. 5 ), the gate insulating layer  124  (of  FIG. 5 ) and the flexible substrate  410  is exposed and the ends of the encapsulation film  470  are disposed on the one of the passivation layer  150 , the interlayer insulating layer  132 , the gate insulating layer  124  and the flexible substrate  410 . 
         [0134]    On the other hand, to prevent damage on the passivation layer  150 , the interlayer insulating layer  132 , or the gate insulating layer  124  by the scribing process and moisture penetration into the display region, all of the passivation layer  150 , the interlayer insulating layer  132  and the gate insulating layer  124  may be removed in the ends of the folding region FR such that the encapsulation film  470  may contact the flexible substrate  410  in the ends of the folding region FR. 
         [0135]    The encapsulation film  470  includes a first inorganic layer  472 , an organic layer  474  and a second inorganic layer  476 . However, it is not limited thereto. 
         [0136]    For example, the encapsulation film  470  may further include an organic layer and an inorganic layer on the second inorganic layer  476  to have a five-layered structure. 
         [0137]    The first and second inorganic layers  472  and  476  have the same plane area and completely overlap each other. 
         [0138]    Alternatively, as shown in  FIGS. 8B and 8C , in a first direction, i.e., an extension direction of the folding region FR, the second inorganic layer  476  may cover a side surface of the first inorganic layer  472  ( FIG. 8B ), and in a second direction, which may be perpendicular to the first direction, the second inorganic layer  476  may have the same width as the first inorganic layer  472  to completely overlap each other ( FIG. 8C ). As a result, the damage on the emitting diode D by moisture penetration in the folding region FR and an area increase of the non-display region in the second direction can be prevented. 
         [0139]    The organic layer  474  is positioned between the first inorganic layer  472  and second inorganic layer  476 . The organic layer  474  has a plane area smaller than the first and second inorganic layers  472  and  476  and is completely overlapped by the first and second inorganic layers  472  and  476 . Namely, the organic layer  474  is completely covered and protected by the second inorganic layer  476  such that moisture penetration through the organic layer  474  is prevented. 
         [0140]    For example, when the organic layer  474  has the same plane area as or larger area than the second inorganic layer  476 , a side surface of the organic layer  474  is exposed and moisture penetration may be generated through the side surface of the organic layer  474 . However, in the present disclosure, since the organic layer  474  is completely covered and protected by the second inorganic layer  476 , moisture penetration through the organic layer  474  is prevented. 
         [0141]    Each of the first inorganic layer  472  and second inorganic layer  476  may be formed of silicon oxide or silicon nitride, and the organic layer  474  may be formed of an epoxy compound or an acryl compound. 
         [0142]    As shown in  FIG. 8B , in the folding region FR (of  FIG. 8A ), the end of the encapsulation film  470  has a first distance D 1  from the flexible substrate  410 . 
         [0143]    On the other hand, as shown in  FIG. 8C , in a side along a second direction, which is perpendicular to an extension direction (i.e., a first direction) of the folding region FR, the end of the encapsulation film  470  has a second distance D 2 , which is smaller than the first distance D 1 , from the flexible substrate  410 . 
         [0144]    In addition, as shown in  FIG. 8D , in a unfolding region, which is a region in the first direction except the folding region FR (of  FIG. 8A ), the end of the encapsulation film  470  has a third distance D 3 , which is smaller than the first distance D 1 , from the end of the flexible substrate  410 . The third distance D 3  may be equal to or different from the second distance D 2 . 
         [0145]    In the ends of the folding region FR, the end of the encapsulation film  470  is positioned to be far away from the end of the flexible substrate  410  such that the damage on the encapsulation film  470  by the folding stress is minimized. 
         [0146]    In addition, in the second direction, which may be perpendicular to the extension direction of the folding region FR, since the end of the encapsulation film  470  is disposed to be relatively close to the end of the flexible substrate  410 , efficiency of the mother substrate is increased. 
         [0147]    Moreover, in the ends of the unfolding region in the first direction, a width of the encapsulation film  470  is increased in comparison to the folding region (FR) such that moisture penetration is minimized. 
         [0148]    Further, as explained in  FIG. 4A , the encapsulation film  470  has a patterned shape, i.e., an island shape, in each cell of the mother substrate, the damage on the encapsulation film  470  by the scribing process is prevented. 
         [0149]    Accordingly, the damage on the emitting diode D by the moisture penetration is prevented, and the production costs of flexible OLED device are reduced. 
         [0150]    It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Technology Category: 5