Patent Publication Number: US-2022238842-A1

Title: Semiconductor device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2014-130279, filed on Jun. 25, 2014, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The present invention is related to a display device and a method of manufacturing the display device. 
     BACKGROUND 
     A display device which uses liquid crystals or OLED (Organic Light Emitting Diode) is conventionally manufactured by forming a display element above a glass substrate. In recent years, display devices are being developed which can curve by forming the display element above a substrate having flexibility (for example, Japanese Laid Open Patent 2007-183605). 
     The radius of curvature when curving a substrate having flexibility becomes smaller the greater the load on a layer formed above the substrate. The load often leads to defects such as breakage. In particular, operational defects occur when a conducting layer breaks. However, from the view point of design and convenience, it is desired that the radius of curvature be reduced as much as possible, that is, bending resistance be improved. 
     The present invention aims to improve the bending resistance of a display device. 
     SUMMARY 
     One embodiment provides a display device including a substrate including a first surface and a second surface and a curved part between the first surface and the second surface, a display element arranged on the first surface, a conducting layer connected with the display element and extending to the second surface from the first surface via the curved part, a plurality of protective layers having lower ductility than the substrate and arranged in the substrate side and/or opposite side to the substrate side with respect to the conducting layer and along the curved part, each of the plurality of protective layers spreading over the curved part, to a certain region of the first surface side from the curved part, and to a certain region of the second side from the curved part. 
     In addition, one embodiment provides a method of manufacturing a display device including forming a display element, conducting layer and a plurality of protective layers in a substrate including a first surface, a second surface and a curved planned region between the first surface and second surface respectively, the display element being formed in at least the first surface, the conducting layer connecting with the display element and extending to the second surface via the curved planned region from the first surface, each of the plurality of protective layers having lower ductility than the substrate, being arranged in the substrate side and/or opposite side to the substrate side with respect to the conducting layer, the protective layer spreading over the curved planned region, to a certain region of the first surface side from the curved planned region, and to a certain region of the second side from the curved planned region, and each of the plurality of the protective layers being arranged along the curved planned region, curving and fixing the substrate in the curved planned region, and baking the substrate. 
     In addition, one embodiment provides a display device including a substrate, a display element arranged in the substrate, a conducting layer connected with the display element and extending in a certain direction, and a plurality of protective layers having lower ductility than the substrate and arranged above a line along a direction different to a direction in which the conductive layer extends in the substrate side and/or opposite side to the substrate side with respect to the conducting layer. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A ˜ FIG. 1B  is a planar view showing an outline structure of a display device in a first embodiment; 
         FIG. 2  is a diagram for explaining a protective layer arranged in a curved part in the first embodiment; 
         FIG. 3  is a diagram for explaining a protective layer arranged in a curved part in the first embodiment; 
         FIG. 4  is a diagram for explaining another example of a protective layer arranged in a curved part in the first embodiment; 
         FIG. 5  is a schematic diagram showing a cross-structure of a display device in the first embodiment; 
         FIG. 6  is a diagram for explaining a process for forming a substrate among the methods of manufacturing a display device in the first embodiment; 
         FIG. 7  is a diagram for explaining a process continuing from  FIG. 6  among the methods of manufacturing a display device in the first embodiment; 
         FIG. 8  is a diagram for explaining a process continuing from  FIG. 7  among the methods of manufacturing a display device in the first embodiment; 
         FIG. 9  is a diagram for explaining a process continuing from  FIG. 8  among the methods of manufacturing a display device in the first embodiment; 
         FIG. 10  is a diagram for explaining a process continuing from  FIG. 9  among the methods of manufacturing a display device in the first embodiment; 
         FIG. 11  is a diagram for explaining a process continuing from  FIG. 10  among the methods of manufacturing a display device in the first embodiment; 
         FIG. 12  is a diagram for explaining a process continuing from  FIG. 11  among the methods of manufacturing a display device in the first embodiment; 
         FIG. 13  is a diagram related to a protective layer in a second embodiment and explains a positional relationship with another layer; 
         FIG. 14  is a diagram related to a protective layer in third embodiment and explains a positional relationship with another layer: 
         FIG. 15  is a diagram related to a protective layer in a fourth embodiment and explains a positional relationship with another layer; and 
         FIG. 16  is a diagram related to a protective layer in a fifth embodiment and explains a positional relationship with another layer. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Each embodiment of the present invention is explained below while referring to the diagrams. Furthermore, the disclosure is merely an example and appropriate modifications could be conceived while maintaining the scope of the invention which are also included in the scope of the present invention. In addition, in order to better clarify the invention, the width and shape etc of each part in drawings are sometimes shown schematically compared to the actual forms and should not be interpreted as limiting the present invention. In addition, in the specification and each drawing, the same reference symbols are attached to similar elements which have previously been described and a detailed explanation of these elements may be omitted where appropriate. 
     First Embodiment 
     [Outline Structure] 
     The display device in one embodiment of the present invention an organic EL (Electro-luminescence) display device which uses an OLED. 
     This display device includes flexibility. Furthermore, the display device in the present embodiment is not limited to a self-emitting type display device such as an organic EL display device and may be a liquid crystal display device using liquid crystals, an electronic paper type display device which uses an electrophoretic element or any other display device. 
     The display device uses an organic resin film which includes flexibility in a substrate. A display element for displaying an image is formed above the substrate including flexibility (sometimes referred to below as flexible substrate). A drive element such as a thin film transistor (TFT) for controlling the light emitting state of an OLED is included in the display element. The flexible substrate is supported by a glass substrate when forming a thin film transistor and is peeled from the glass substrate in the manufacturing process of the display device. 
     [External Appearance of a Display Device  1 ] 
       FIG. 1A ˜ 1 B are planar diagrams showing a schematic structure of a display device  1  in one embodiment. As is shown in  FIG. 1A , the display device  1  is arranged with a display region D 1 , D 2 , a scanning line drive circuit  103 , a driver IC  104  and a FPC (Flexible Printed Circuit)  106 . These are formed in a flexible substrate  10 . 
     The flexible substrate  10  includes a first surface S 1  including the first display region D 1 , a second surface S 2  including the display region D 2 , and a third surface S 3  including the scanning line drive circuit  103 . A display element is formed in the display regions D 1 , D 2 . In this way, the display regions D 1  and D 2  can display an image. The first surface S 1  and second surface S 2  are curved so that angle of approximately 90 degrees is formed. A bent region, that is, a region between the first surface S 1  and second surface S 2  is referred to as curved part C (see  FIG. 2  for example). The relationship between the first surface S 1  and third surface S 3  is the same as the relationship between the first surface S 1  and second surface S 2  in that they curve so as to form an angle of approximately 90 degrees. Furthermore, the curved angle is not limited to 90 degrees and may be 90 degrees or less and 90 degree or more. 
     When a part of a surface curves in this way, for example it is possible to arrange a display region as large as possible on the largest surface in a mobile terminal (smartphone etc) having a roughly rectangular case and form a drive circuit on a side surface. In addition, it is possible to arrange a display on a side surface. In addition, it is possible to adjust the curved angle of each surface of the display device  1  to the shape of a casing other than a rectangle and arrange a display region and drive circuit etc. 
     Furthermore, it is not necessary for a display region to exist on the second surface  2  and in this case a drive circuit of a circuit included in the display region  1  or a device such as a sensor which receives inputs from a user may be arranged. In addition, a display region may also be arranged on the third surface S 3 . As is shown in  FIG. 1A , the present invention is not limited to three surfaces, two surfaces or more than three surfaces may be included. 
     A case having a fourth surface is exemplified as a case where more surfaces are included. For example, a fourth surface S 4  may be arranged in an end part (edge facing an edge of the first surface S 1  side) of the second surface S 2 . The fourth surface S 4  may be formed on another edge side of the second surface S 2  or formed on an edge side opposite the FPC  106  of the first surface S 1 . 
     Scanning line  101  which extends to the second surface S 2  via the first surface S 1  from the third surface S 3  and data signal line  102  which crosses perpendicularly with the scanning line  101  are arranged in the display region D 1 . A pixel  105  is arranged in a position corresponding to an intersection point between the scanning line  101  and the data signal line  102 . The pixel  105  is arranged in a matrix shape. Furthermore, although one signal line extending in a direction along the scanning line  101  or data signal line  102  per pixel  105  is shown in  FIG. 1A , a plurality of signal lines may also be arranged. In addition, wiring which supplies a certain voltage such as a power source line may be arranged in the display region D 1 . 
     Although a description is omitted in  FIG. 1A , a pixel  105  may also be arranged in the display region D 2  the same as the display region D 1 . 
     The scanning line drive circuit  103  supplies a control signal to a scanning line  101 . The driver IC  104  supplies a data voltage to a data signal line  102  and controls the scanning drive circuit  104 . A display element including for controlling emitted light based on a control signal and a data voltage, and a light emitting element (OLED) which is controlled by the pixel circuit are arranged in each pixel  105 . The pixel circuit includes a thin film transistor and capacitor for example, the thin film transistor is driven by a control signal and data voltage and controls the emitted light of a light emitting element. An image is displayed in the display regions D 1 , D 2  by control of the emitted light. 
     In addition, an opposing substrate  20  (see  FIG. 5  for example) is bonded to the flexible substrate  10  so as to cover a pixel circuit of each pixel  105 . The opposing substrate  20  is an organic resin layer having flexibility. A color filter and light blocking material and the like may also be formed on the opposing substrate  20 . In this example, a filler is filled between the flexible substrate  10  and opposing substrate  20 . 
       FIG. 1B  shows a state before the second surface S 2  and third surface S 3  are curved. Each manufacturing process is performed in at least the stated shown in  FIG. 1B  until a display element is formed in the flexible substrate  10  and the opposing substrate  20  is bonded. Following this, the second surface S 2  and third surface S 3  are curved with respect to the first surface S 1  respectively. 
     In this example, the second surface S 2  and third surface S 3  are curved with respect to the first surface and baked in a state fixed to a metal mold or the like. The driver IC  104  and FPC  106  may be attached to the display device  1  shown in  FIG. 1A  or attached to the display device  1  shown in  FIG. 1B . 
     Next, a region Z 1  shown in  FIG. 1A , that is, a curved part between the first surface S 1  and second surface S 2  is explained using  FIG. 2 . 
     [Structure of a Protection Layer  50 ] 
       FIG. 2  is a diagram for explaining a protection layer  50  arranged in a curved part C in the first embodiment. In the explanation below, a region in which the flexible substrate  10  is curved between the first surface S 1  and second surface S 2  is referred to as curved part C. A scanning line  101  which is a conducting layer extends to the second surface  32  from the first surface S 1  via the curved part C. The scanning line  101  is connected with a display element of the display region D 1  and a display element of the display region D 2 . 
     In this example, the protection layer  50  is arranged so as to cover the scanning line  101 . The protection layer  50  is formed using a material with lower ductility than the flexible substrate  10 . For example, in the case where the flexible substrate  10  is formed using polyimide, the protection layer  50  is formed using an acrylic resin. 
     The protection layer  50  covers the scanning line  101  in a certain area of the curved part C and the first surface S 1  side from the curved part C, and a certain area of the second surface S 2  side from the curved part C. The certain area of the first surface S 1  is an area different to the display region D 1  and is determined so as not to overlap the display region D 1 . Similarly, the certain area of the second surface S 2  is an area different to the display region D 1  and is determined so as not to overlap the display region D 2 . 
     In the example in  FIG. 2 , one protection layer  50  is formed with respect to one scanning line  101 . In this way, the protection layer  50  is formed in an island shape and is arranged along the curved part C (along the boundary between the first surface S 1  and second surface S 2  in the case shown in  FIG. 1A ). Furthermore, the protection layer  50  may be formed in an island shape and one protection layer  50  may be formed with respect to a plurality of scanning lines  101 . As described above, the protection layer is formed using a material with lower ductility than the flexible substrate  10 . In order to easily curve the flexible substrate  10  in the curved part C, it is preferred to reduce the area occupied by the protection layer  50  which is a material with low ductility in the cured part C. Therefore, while the protection layer  50  is arranged so as to cover the scanning line  101  in the curved part C, it is preferred that a region in which the protection layer  50  does not exists is arranged between adjacent scanning lines  101 . 
     In addition, it is possible to suppress peeling of the protection layer  50  from the flexible substrate  10  by spreading the protection layer  50  up to the first surface S 1  and second surface S 2  from the curved part C. On the other hand, when the protection layer  50  is spread widely in the first surface S 1  and second surface S 2 , the effects of stress produced in the curved part C are transmitted to other regions (for example, display regions D 1  and D 2 ). Therefore, it is preferred that the protection in the first surface S 1  and second surface S 2  does not ad as far as the display regions D 1 , D 2 . 
     In addition, it order to suppress peeling of the protection layer  50  from the flexible substrate  10 , it is preferred that a pattern periphery edge part of the protection layer  50  does not include an angle. Therefore, as is shown in  FIG. 2 , it is preferred that the four corner  50 C of a pattern are formed into curved lines and the pattern periphery edge part of the protection layer  50  is formed into a pattern which is enclosed by lines which do not have a vertex. 
       FIG. 3  is a diagram for explaining the protection layer  50  in a curved part in the first embodiment.  FIG. 3  shows the protection layer  50  in a state before the second surface S 2  and third surface S 3  shown in  FIG. 1B  are curved. As is shown in  FIG. 3 , in the case where the first surface S 1  and second surface S 2  are positioned on the same planar surface, the curved part C is the region intended to be curved (referred to below as curved planned region). The scanning line  101  extends across the curved planned region. In addition, the protection layer  50  is formed in a straight line in a different direction to the direction in which the scanning line  101  extends. The curved planned region spreads along the straight line. 
     The substrate changes into the shape shown in  FIG. 2  when the flexible substrate  10  is curved in the direction of the arrow in  FIG. 3 . At this time, a force is applied in to the scanning line in a pulling direction (direction in which it is easily broken), On the other hand, by providing the protection layer  50  which has lower ductility than the flexible substrate  10  in the curved part C, the protection layer  50  produces a force in a direction which compresses the flexible substrate  10 . Therefore, it is possible to relieve the force whereby the flexible substrate  10  pulls the scanning line  101 . 
     When the flexible substrate  10  is baked in a curved state, the stress applied to an organic resin such as the flexible substrate  10  and protection layer  50  is relieved. In this way, the shape of the flexible substrate  10  can be easily maintained in a curved state. 
       FIG. 4  is a diagram for explaining another example of a protection layer arranged in a curved part C in the first embodiment. In the example described above, the protection layer  50  covers the scanning line  101 , that is, the protection layer  50  is arranged further to the opposite side (referred to simply as upper layer side below) of the flexible substrate  10  than the scanning line  101 . On the other hand, reversely, the protection layer  50  may be arranged further to the flexible substrate  10  side (referred to simply as lower layer side below) than the scanning layer  101 . Even in this case, the protection layer  50  adds a force in the direction where the flexible substrate  10  is compressed. Therefore, it is possible for the flexible substrate  10  to relieve the force which pulls the scanning line  101 . 
     Furthermore, by combining  FIG. 2  and  FIG. 4 , the protection layer  50  may be arranged on both sides (upper layer side and lower layer side) of the scanning line  101 . The positional relationship between the protection layer  50  and scanning line  101  is described in detail below. 
     [Cross-Sectional Structure of the Display Device  1 ]  FIG. 5  is a schematic diagram showing a cross-sectional structure of a display device in the first embodiment. In  FIG. 5  and  FIG. 6  to  FIG. 12  described below, D 1 , D 2 , S 1 , S 2 , S 3  and C correspond to the display region D 1 , first surface S 1 , second surface  32 , third surface  33  and curved part C described above. In addition, TA refers to a region arranged with terminal connected to the exterior parts such as FPC  106  and the like. 
     A thin film transistor  110  is arranged in the flexible substrate  10 . An interlayer insulation layer  111  is arranged so as to cover the thin film transistor  110 . A wiring layer  112  is arranged above the interlayer insulation layer  111 . The wiring layer  112  is connected to the thin film transistor  110  via a contact hole arranged in the interlayer insulation layer  111 . 
     An interlayer organic layer  151  is arranged to cover a wiring layer  112  in the display region D 1  and a pixel electrode layer  114  is arranged above the interlayer organic layer  151 . The pixel electrode layer  114  is connected to the wiring layer  12  via a contact hole arranged in the interlayer organic layer  151 . A rib organic layer  153  is arranged to expose a part of the pixel electrode layer  114  and cover an end part of the pixel electrode layer  114 . A light emitting layer  120  is arranged to be connected with the exposed pixel electrode layer  114 . 
     The light emitting layer  120  includes an OLED, a translucent electrode which allows light to pass through from the OLED, and a sealing layer which seals the OLED and translucent electrode. In this example, when a current is supplied to the OLED via the translucent electrode and pixel electrode layer  114 , light from the OLED passes through the translucent electrode and is emitted to the opposing substrate  20  side. This structure is generally called a top emission type structure. Furthermore, the reverse of the top emission type structure may be adopted in which light is emitted to the flexible substrate  10  side called a bottom emission type structure. 
     These structures which exist in the display region D 1  correspond to a display element. 
     The interlayer organic layer  151  is removed in the vicinity of the curved part C and the wiring layer  112  and pixel electrode layer  114  are stacked. In this example, the scanning line  101  is formed using the stacked structure of the wiring layer  112  and pixel electrode layer  114 . The rib organic layer  153  corresponding to the protection layer  50  described above is formed above the pixel electrode layer  114  in the curved part C and a certain region of the first surface S 1  side from the curved part C, and a certain region of the second side surface S 2  from the curved part C. 
     In a region which includes at least the display regions D 1 , D 2  except the terminal region TA in  FIG. 5  (in this example, a region which further includes the vicinity of the curved part C), each structure which exists in each region is covered by the opposing substrate  20 . A filler  170  is filled between each structure formed on the opposing substrate  20  and flexible substrate  10  side. Furthermore, a sealing material may be arranged so as to enclose the filler  170  along the periphery edge part of the opposing substrate  20 . 
     Furthermore, the second surface  32  has the same structure as the display region D 1 . In addition, the third surface  33  has a structure using a part of a display element of the display region D 1  in which a drive circuit etc is formed using the thin film transistor  110 . A similar structure as the curved part C between the first surface S 1  and second surface S 2  exists in the curved part C between the first surface S 1  and third surface  33 . 
     [Manufacturing Method of the Display Device  1 ] 
     Next, a manufacturing method of the display device  1  described above is explained using  FIG. 6  to  FIG. 12 . 
       FIG. 6  is a diagram for explaining a process for forming a substrate in the manufacturing method of the display device  1  in the first embodiment. The flexible substrate  10  is formed above a glass substrate  30 . The flexible substrate  10  is an organic resin layer and in this example is formed from polyimide. For example, the flexible substrate  10  is formed on the glass substrate  30  by coating and baking a solution containing polyimide above the glass substrate  30 . The thickness of the flexible substrate  10  is 1 μm or more and 100 μm or less and preferably 5 μm or more and 50 μm or less. Furthermore, the flexible substrate  10  is not limited to polyimide and may be formed from another organic resin layer. However, the flexible substrate  10  is preferred to be formed from a material having a maximum temperature (at least 300° C., preferably 400° C.) heat resistance in a thermal process when forming the thin film transistor  110 . 
     The glass substrate  30  is used as a support substrate for supporting the flexible substrate  10  when forming a display element and the like in the flexible substrate  10 . Furthermore, it is not always necessary to use a support substrate. 
       FIG. 7  is a diagram for explaining a process continuing from  FIG. 6  in the manufacturing method of the display device in the first embodiment. The thin film transistor  110  is formed in the flexible substrate  10 . A silicon oxide or silicon nitride insulation layer is formed between the flexible substrate  10  and thin film transistor  110 . The infiltration of moisture or gas to the interior is suppressed by this insulation layer. 
     Next; the interlayer insulation layer  111  is formed so as to cover the thin film transistor  110 . The interlayer insulation layer  111  may be formed by a silicon oxide or silicon nitride insulation layer or an insulation layer using an organic resin. 
       FIG. 8  is a diagram for explaining a process continuing from  FIG. 7  in the manufacturing method of the display device in the first embodiment. A part of the interlayer insulation layer  111  formed as described above is etched and a part (source and drain of a semiconductor layer and gate electrode etc) of the thin film transistor  110  is exposed. In addition, the wiring layer  112  is formed into a certain pattern after etching the interlayer insulation layer  111 . The wiring layer  112  is a conducting layer such as the scanning line  101  or data signal line  102  described above and is connected with the thin film transistor  110  exposed in a region where the interlayer insulation layer  111  is etched. This conducting layer is formed by stacking a metal such as aluminum or titanium for example, 
       FIG. 9  is a diagram for explaining a process continuing from  FIG. 8  in the manufacturing method of the display device in the first embodiment. A part of the wiring layer  112  is exposed and the interlayer organic layer  151  is formed. In this example, the interlayer organic layer  151  is an acrylic resin. The interlayer organic layer  151  is formed by coating a photosensitive acrylic resin on the flexible substrate  10  formed with each structure described above a certain pattern is formed by exposing, developing and baking. 
     Furthermore, the interlayer organic layer  151  is not limited to acrylic resin and may be formed using another organic resin. However, the interlayer organic layer  151  is preferred to be a material with lower ductility than the flexible substrate  10 . As in the embodiments described below, in the case where the interlayer organic layer  151  is used as the protection layer  50 , a material with lower ductility than the flexible substrate  10  is used for the interlayer organic layer  151 . The thickness of the interlayer organic layer  151  is 0.5 μm or more and 10 μm or less for example, and preferably 1 μm or more and 5 μm or less. 
       FIG. 10  is a diagram for explaining a process continuing from  FIG. 9  in the manufacturing method of the display device in the first embodiment. The pixel electrode layer  114  is formed above the interlayer organic layer  151  formed with the pattern described above. In this example, a metal oxide such as ITO (Indium Tin Oxide) is used for the pixel electrode layer  114  and an anode electrode of the OLEO is formed. In addition, in this example, the pixel electrode layer  114  is arranged above the wiring layer  112  in the vicinity of the curved part C to form the scanning line  101  using a stacked structure. Furthermore, the scanning line  101  may be formed in either the wiring layer  112  or pixel electrode layer  114  in the vicinity of the curved part C. 
       FIG. 11  is a diagram for explaining a process continuing from  FIG. 10  in the manufacturing method of the display device in the first embodiment. A part of the pixel electrode layer  114  is exposed and the rib organic layer  153  is formed. In this example the rib organic layer  153  is an acrylic resin. The rib organic layer  153  is formed by coating a photosensitive acrylic resin on the flexible substrate  10  formed with each structure described above and a desired pattern is formed by exposing, developing and baking. Furthermore, the rib organic layer  153  is not limited to an acrylic resin and can be formed from another organic resin. However, the rib organic layer  153  used as the protection layer  50  is required to be a material with lower ductility than the flexible substrate  10 . Furthermore, the rib organic layer  153  is not limited to this structure in the case where the rib organic layer  153  is not used as the protection layer  50  as is described in the embodiments below. The thickness of the rib organic layer  153  is 0.5 μm or more and 10 μm or less for example, and preferably 1 μm or more and 5 μm or less. 
     The rib organic layer  153  is formed so as to cover the periphery edge part of the pixel electrode layer  114  in the display region D 1 . In addition, the rib organic layer  153  is arranged in the curved part C and across a certain region on both sides of the curved part C in the vicinity of the curved part C and the protection layer  50  described above is formed. 
       FIG. 12  is a diagram for explaining a process continuing from  FIG. 11  in the manufacturing method of the display device in the first embodiment. The light emitting layer  120  is formed after forming the rib organic layer  153 . Following this, a display element of at least the display region D 1  and D 2  is sealed by the opposing substrate  20 . An acrylic resin filler  170  is filled between the opposing substrate  20  and flexible substrate  10  when sealing is performed. Furthermore, in this example the vicinity of the curved part C is also sealed by the opposing substrate  20 . 
     The opposing substrate  20  is formed from a material having flexibility such as an organic resin layer the same as the flexible substrate  10 . A color filter and light blocking layer and the like may also be formed in the opposing substrate  20 . 
     Following this, light such as a laser is irradiated from the glass substrate  30  side towards to the flexible substrate  10  and the glass substrate  30  is peeled from the flexible substrate  10 . When laser light is irradiated from the glass substrate  30  side, the laser light is absorbed by the organic resin layer at the boundary between the flexible substrate  10  and glass substrate  30  and heated. In this way, the organic resin layer breaks up, an adhesive force between the glass substrate  30  and the flexible substrate  10  is weakened and peeling becomes possible. In this way, the display device  1  shown in  FIG. 1B  and  FIG. 5  is manufactured. 
     In addition, as described above the display device  1  shown in  FIG. 1A  is completed when the second surface S 2  and third surface S 3  are cured and fixed with respect to the first surface S 1  and baked while in a fixed state. The baking temperature is 60° C. or more and 250° C. or less. In the case where an OLED is used in the display element, it is preferred that the sintering temperature is 60° C. or more and 100° C. or less and more preferably 70° C. or more and 80° C. or less considering the heat resistance of the OLED. Furthermore, in the case where a material with high heat resistance is used in the display element, or in the case when baking described above is performed before forming a material (OLED for example) with low heat resistance included in the display element, the baking temperature is 200° C. or more and 240° C. or less and more preferably 220° C. or more and 230° C. or less. 
     As described above, when the second surface S 2  and third surface  33  are curved with respect to the first surface S 1 , the scanning line  101  is applied with a force in a pulling direction (direction in which it breaks easily) due to the effects of the thickness of the flexible substrate  10 . As in the first embodiment, by providing the protection layer  50  which has lower ductility than the flexible substrate  10  in the curved part C, the protection layer  50  generates a force in the direction in which the flexible substrate  10  is compressed. Therefore, it is possible for the flexible substrate  10  to relieve the force pulling the scanning line  101 . In this way, in the case where a curved region is determined in advance, by arranging the protection layer  50  corresponding to a position of a conducting layer such as the scanning line  101 , it is possible to improve bending resistance properties of this region. 
     Second Embodiment 
     The interlayer organic layer  151  is used as the protection layer  50  in the second embodiment. 
       FIG. 13  is related to the protection layer  50  in the second embodiment and explains a positional relationship with other layers. As is shown in  FIG. 13 , the interlayer organic layer  151  is used as the protection layer  50  and the pixel electrode layer  114  is provided (corresponding to  FIG. 4 ) above the protection layer  50 , That is, in this example the protection layer  50  is sandwiched between the pixel electrode layer  114  and wiring layer  112 . 
     In this case, the interlayer organic layer  151  is formed with a material having lower ductility than the flexible substrate  10 . By adopting this structure, the load on the scanning layer  101  (wiring layer  112  and pixel electrode layer  114 ) in the curved part C is reduced by providing the protection layer  50  and it is possible to improve bending resistance properties. 
     Third Embodiment 
     The interlayer organic layer  151  and rib organic layer  153  are used as the protection layer  50  in the third embodiment. 
       FIG. 14  is related to the protection layer  50  in the third embodiment and explains a positional relationship with other layers. As is shown in  FIG. 14 , the interlayer organic layer  151  and rib organic layer  153  are provided in the vicinity of the curved part C and these form the protection layer  50 . In this example, the interlayer organic layer  151  is spread wider than the rib organic layer  153 . The rib organic layer  153  is provided only in the interior of the curve part C. 
     In this example, the pixel electrode layer  114  is sandwiched between the interlayer organic layer  151  and the rib organic layer  153 . That is, the pixel electrode layer  114  is sandwiched by the protection layer  50 . 
     The interlayer organic layer  151  and rib organic layer  153  are formed with a material having lower ductility than the flexible substrate  10 . 
     Furthermore, the rib organic layer  153  may be formed with a material having lower ductility than the interlayer organic layer  151  as well as the flexible substrate  10 . 
     By adopting this structure, the load on the scanning line  101  (wiring layer  112  and pixel electrode layer  114 ) in the curved part C is reduced by providing the protection layer  50  and it is possible to improve bending resistance properties. 
     Fourth Embodiment 
     The size relationship of the interlayer organic layer  151  and rib organic layer  153  in the third embodiment is in a reverse relationship in the fourth embodiment. 
       FIG. 15  is related to the protection layer  50  in the fourth embodiment and explains a positional relationship with other layers. As is shown in  FIG. 15 , the interlayer organic layer  151  and rib organic layer  153  are provided in the vicinity of the curved part C and these form the protection layer  50 . In this example, the rib organic layer  153  is spread wider than the interlayer organic layer  151 . The interlayer organic layer  151  is provided only in the interior of the curve part C. 
     In this example, the pixel electrode layer  114  is sandwiched between the interlayer organic layer  151  and the rib organic layer  153 . That is, the pixel electrode layer  114  is sandwiched by the protection layer  50 . 
     The interlayer organic layer  151  and the rib organic layer  153  are each formed with a material having material having lower ductility than the flexible substrate  10 . Furthermore, the rib organic layer  153  may be formed with a material having lower ductility than the interlayer organic layer  151  as well as the flexible substrate  10 . 
     By adopting this structure, the load on the scanning line  101  (wiring layer  112  and pixel electrode layer  114 ) in the curved part C is reduced by providing the protection layer  50  and it is possible to improve bending resistance properties. 
     Fifth Embodiment 
     The interlayer organic layer  151  and rib organic layer  153  in the third and fourth embodiments are spread from the curved part C to the first surface S 1  side and second surface S 2  side respectively in the fifth embodiment. 
       FIG. 16  is related to the protection layer  50  in the fifth embodiment and explains a positional relationship with other layers. As is shown in  FIG. 16 , the interlayer organic layer  151  and rib organic layer  153  are provided in the vicinity of the curved part C and these form the protection layer  50 . In this example, the rib organic layer  153  is spread wider than the interlayer organic layer  151 . Either the interlayer organic layer  151  or the rib organic layer  153  are spread from the curved part C to the first surface S 1  side and the second surface S 2  side. Furthermore, the size relationship between the interlayer organic layer  151  and rib organic layer  153  may be a reverse relationship. 
     In this example, the pixel electrode  114  is sandwiched in at least the entire curved part C by the interlayer organic layer  151  and rib organic layer  153 . That is, the pixel electrode  114  is sandwiched by the protection layer  50  in at least the entire curved part C. 
     The interlayer organic layer  151  and the rib organic layer  153  are each formed with a material having material having lower ductility than the flexible substrate  10 . Furthermore, the rib organic layer  153  may be formed with a material having lower ductility than the interlayer organic layer  151  as well as the flexible substrate  10 . 
     By adopting this structure, the load on the scanning line  101  (wiring layer  112  and pixel electrode layer  114 ) in the curved part C is reduced by providing the protection layer  50  and it is possible to improve bending resistance properties. Since the pixel electrode  114  is easier to break in the case where it is formed from a metal oxide rather than a metal layer, it is possible to further improve bending resistance properties by sandwiching the pixel electrode layer  114  between an upper and lower layer using the protection layer  50  in the entire curved part C. 
     In the category of the concept of the present invention, a person ordinarily skilled in the art could conceive of various modifications and correction examples and could understand that these modifications and correction examples belong to the scope of the present invention. For example, with respect to each embodiment described above, a person ordinarily skilled in the art could appropriately perform an addition or removal of structural components or design modification or an addition of processes or an omission or change in conditions which are included in the scope of the present invention as long as they do not depart from the subject matter of the present invention.