Patent Publication Number: US-2017351365-A1

Title: Display device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims the benefit of priority from the prior Japanese Patent Application No. 2016-112484, filed on Jun. 6, 2016, the entire contents of which are incorporated herein by reference. 
     FIELD 
     An embodiment of the present invention relates to a display device such as an organic EL display device and a manufacturing method thereof. For example, an embodiment relates to a display device on which a touch panel is mounted and a manufacturing method thereof. 
     BACKGROUND 
     A touch panel has been known as an interface for a user to input information. Arrangement of a touch panel over a screen of a display device allows a user to operate input buttons, icons, and the like displayed on a screen, by which information can be readily input to a display device. For instance, Japanese patent application publications No. 2001-154178 and No. 2001-117719 disclose a stacked-type display device in which a touch panel is installed over a liquid crystal display device. 
     SUMMARY 
     An embodiment of the present invention is a display device which includes: a base film having a display region, a touch region, and a boundary region between the display region and the touch region; an image-display portion provided in the display region; and a touch portion provided in the touch region. The image-display portion has a transistor including a gate electrode and a source/drain electrode. The touch portion has a plurality of electrodes electrically connected to each other with a connection electrode. The connection electrode exists in the same layer as one of the gate electrode and the source/drain electrode. The base film is folded in the boundary region so that a back surface of the touch portion opposes the image-display portion with the touch portion sandwiched therebetween. The image-display portion and the touch portion are sandwiched by the base film. The back surface of the touch portion is one of two surfaces of the touch portion opposing each other, which is closer to the base film. 
     An embodiment of the present invention is a display device which includes: a base film having a display region, a touch region, and a boundary region between the display region and the touch region; an image-display portion over the display region; and a touch portion over the touch region. The baes film is folded in the boundary region so that a front surface of the touch portion overlaps with the image-display portion with the touch portion sandwiched therebetween. The boundary region protrudes from a region in which the image-display portion and the touch portion overlap with each other, and the base film in a protruding portion has a three-folded structure. The front surface of the touch portion is one of two surfaces of the touch portion opposing each other, which is farther from the base film. 
     An embodiment of the present invention is a display device which includes: a base film having a display region, a touch region, and a boundary region between the display region and the touch region; an image-display portion over the display region; and a touch portion over the touch region. The baes film is folded in the boundary region so that a front surface of the touch portion overlaps with the image-display portion with the touch portion sandwiched therebetween. The base film in the boundary region has a three-folded structure and is sandwiched between the display region and the touch region. The front surface of the touch portion is one of two surfaces of the touch portion opposing each other, which is farther from the base film. 
     An embodiment of the present invention is a manufacturing method of a display device. The manufacturing method includes; forming a display panel and a touch panel over a base film; and folding the base film in a region sandwiched between the display panel and the touch panel so that a touch region is located over and overlaps with a display region and the base film extends from under the display panel to over the touch panel. 
     An embodiment of the present invention is a manufacturing method of a display device. The manufacturing method includes: forming a display panel and a touch panel over a base film; forming a slit in the base film in a region between the display panel and the touch panel; and three-folding the region so that the touch panel is located and overlaps with the display panel and the base film under the touch panel is sandwiched between the display panel and the touch panel. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  and  FIG. 1C  are schematic top views, and  FIG. 1B  is a schematic cross-sectional view of a display device according to an embodiment of the present invention; 
         FIG. 2  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 3  is a schematic top view of a touch portion of a display device according to an embodiment of the present invention; 
         FIG. 4  is a schematic top view of an image-display portion of a display device according to an embodiment of the present invention; 
         FIG. 5  is a schematic cross-sectional view of a display device according to an embodiment of the present invention; 
         FIG. 6A  and  FIG. 6B  are schematic cross-sectional views showing a manufacturing method of a display device according to an embodiment of the present invention; 
         FIG. 7A  and  FIG. 7B  are schematic cross-sectional views showing a manufacturing method of a display device according to an embodiment of the present invention; 
       FIG. 8 A and  FIG. 8B  are schematic cross-sectional views showing a manufacturing method of a display device according to an embodiment of the present invention; 
       FIG. 9 A and  FIG. 9B  are schematic cross-sectional views showing a manufacturing method of a display device according to an embodiment of the present invention; 
         FIG. 10A  and  FIG. 10B  are schematic cross-sectional views showing a manufacturing method of a display device according to an embodiment of the present invention; 
         FIG. 11A  and  FIG. 11B  are schematic cross-sectional views showing a manufacturing method of a display device according to an embodiment of the present invention; 
         FIG. 12A  and  FIG. 12B  are schematic cross-sectional views showing a manufacturing method of a display device according to an embodiment of the present invention; 
         FIG. 13A  and  FIG. 13B  are schematic cross-sectional views showing a manufacturing method of a display device according to an embodiment of the present invention; 
         FIG. 14  is a schematic cross-sectional view showing a manufacturing method of a display device according to an embodiment of the present invention; 
         FIG. 15A  and  FIG. 15B  are schematic cross-sectional views of a display device according to an embodiment of the present invention; 
         FIG. 16  is a schematic cross-sectional view of a display device according to an embodiment of the present invention; 
         FIG. 17  is a schematic cross-sectional view of a display device according to an embodiment of the present invention; 
         FIG. 18  is a schematic top view of a display device according to an embodiment of the present invention; 
         FIG. 19  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 20  is a schematic top view of a display device according to an embodiment of the present invention; 
         FIG. 21  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 22  is a schematic top view of a display device according to an embodiment of the present invention; 
         FIG. 23  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 24  is a schematic top view of a display device according to an embodiment of the present invention; 
         FIG. 25A  to  FIG. 25C  are schematic cross-sectional views of a display device according to an embodiment of the present invention; 
         FIG. 26  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 27  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 28  is a schematic top view of a display device according to an embodiment of the present invention; 
         FIG. 29A  to  FIG. 29C  are schematic cross-sectional views of a display device according to an embodiment of the present invention; 
         FIG. 30  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 31  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 32  is a schematic top view of a display device according to an embodiment of the present invention; 
         FIG. 33A  to  FIG. 33C  are schematic cross-sectional views of a display device according to an embodiment of the present invention; 
         FIG. 34  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 35  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 36  is a schematic top view of a display device according to an embodiment of the present invention; 
         FIG. 37A  and  FIG. 37B  are respectively a schematic cross-sectional view and side view of a display device according to an embodiment of the present invention; 
         FIG. 38  is a schematic top view of a display device according to an embodiment of the present invention; 
         FIG. 39  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 40  is a schematic top view of a display device according to an embodiment of the present invention; 
         FIG. 41  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 42  is a schematic top view of a display device according to an embodiment of the present invention; 
         FIG. 43  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 44A  and  FIG. 44B  are schematic top views of a display device according to an embodiment of the present invention; 
         FIG. 45A  to  FIG. 45C  are schematic cross-sectional views of a display device according to an embodiment of the present invention; 
         FIG. 46  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 47A  and  FIG. 47B  are schematic top views of a display device according to an embodiment of the present invention; 
         FIG. 48  is a schematic developed view of a display device according to an embodiment of the present invention; 
         FIG. 49  is a top view showing a manufacturing method of a display device according to an embodiment of the present invention; and 
         FIG. 50  is a top view showing a manufacturing method of a display device according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, the embodiments of the present invention are explained with reference to the drawings. The invention can be implemented in a variety of different modes within its concept and should not be interpreted only within the disclosure of the embodiments exemplified below. 
     The drawings may be illustrated so that the width, thickness, shape, and the like are illustrated more schematically compared with those of the actual modes in order to provide a clearer explanation. However, they are only an example, and do not limit the interpretation of the invention. In the specification and the drawings, the same reference number is provided to an element that is the same as that which appears in preceding drawings, and a detailed explanation may be omitted as appropriate. 
     In the present invention, when a plurality of films is formed by processing one film, the plurality of films may have functions or rules different from each other. However, the plurality of films originates from a film which is formed as the same layer in the same process. Therefore, the plurality of films is defined as films existing in the same layer. 
     In the specification and the scope of the claims, unless specifically stated, when a state is expressed where a structure is arranged “over” another structure, such an expression includes both a case where the substrate is arranged immediately above the “other structure” so as to be in contact with the “other structure” and a case where the structure is arranged over the “other structure” with an additional structure therebetween. 
     First Embodiment 
     1. Outline Structure 
     In the present embodiment, a structure of a display device  100  of an embodiment of the present invention is explained by using  FIG. 1A  to  FIG. 5 . 
     Schematic top views of the display device  100  of the present embodiment are shown in  FIG. 1A  and  FIG. 1C , and a schematic cross-sectional view along a chain line A-A′ of  FIG. 1A  is shown in  FIG. 1B . As shown in  FIG. 1B , the display device  100  has a base film  102 , and the base film  102  possesses a display region  120 , a touch region  140 , and a boundary region  160  between the display region  120  and the touch region  140 . The touch region  140  is located over and overlaps with the display region  120 . The boundary region  160  connects the display region  120  to the touch region  140 . The base film  102  is a plate or a film with flexibility and has a light-transmitting property to visible light. 
     An image-display portion  122  is provided over the base film  102  in the display region  120 . As described below, a plurality of pixels is disposed in the image-display portion  122 . A driver circuit and the like for driving the pixels can be provided to the display region  120 , and an image is reproduced on the image-display portion  122  by the plurality of pixels. 
     A touch portion  142  is provided under the base film  102  in the touch region  140 . The touch portion  142  is the same or substantially the same in size and shape as the image-display portion  122  and overlaps with the image-display portion  122  ( FIG. 1A ). As described below, the touch portion  142  has a function to sense a touch by contacting (hereinafter, referred to as touch) with an object such as a finger and a palm through the base film  102  and serves as an interface for inputting information by a user. For example, an electrostatic capacity type, a resistive film type, an electromagnetic induction type can be employed in the touch portion  142 . As shown in  FIG. 1A , a user recognizes the image-display portion  122  through the touch portion  142 . 
     As described above, the base film  102  in the display region  120  and the base film  102  in the touch region  140  are connected to each other in the boundary region  160 . In other words, the base film  102  in the boundary region  160 , the base film  102  in the display region  120 , and the base film  102  in the touch region  140  are integrated, and the base film  102  in the display region  120  extends from under the image-display portion  122  to over the touch portion  142  through the boundary region  160 . Therefore, the base films  102  of the display region  120 , the boundary region  160 , and the touch region  140  have a continuous structure, and the image-display portion  122  and the touch portion  142  are enclosed by the base film  102 . 
     The display region  120  further possesses a plurality of first terminals  124  and a plurality of second terminals  126  over the base film  102 . Each of the plurality of first terminals  124  and the plurality of second terminals  126  is arranged so that at least part of them does not overlap with the base film  102  of the touch region  140 . That is, each of the first terminals  124  and the plurality of second terminals  126  is at least partially exposed from the base film  102  of the touch region  140 . 
     The first terminals  124  and the second terminals  126  are arranged at a vicinity of a side (first side)  128  of the image-display portion  122  substantially parallel to the first side  128 . The first terminals  124  are electrically connected to the image-display portion  122  through wirings  130  provided over the base film  102 . On the other hand, the second terminals  126  are electrically connected to the touch portion  142  through wirings  132  formed over the base film  102  in the display region  120 . In  FIG. 1A , the plurality of second terminals  126  is illustrated so as to sandwich the plurality of first terminals  124 . However, the second terminals  126  may be collectively provided in one specified place. 
     As shown in  FIG. 1C , the first terminals  124  and the second terminals  126  are connected to a connector  170  such as a flexible printed circuit substrate (FPC), and signals are input to the image-display portion  122  and the touch portion  142  from an external circuit through the connector  170 , the first terminals  124 , and the second terminals  126 . For example, the first terminals  124  are supplied with image signals and a power source, and the second terminals  126  are supplied with detection signals for detecting a touch, and the like. 
     As shown in  FIG. 1A  to  FIG. 1C , the first terminals  124  and the second terminals  126  each are provided over the base film  102  in the display region  120  and are arranged at the vicinity of the first side  128  so as to be parallel to the first side  128 . Hence, the first terminals  124  and the second terminals  126  can be connected to a single connector  170 . Hence, compared with a case where the first terminals  124  and the second terminals  126  are connected to different connectors, the number of the connectors can be reduced by half, thereby decreasing manufacturing cost and simplifying a manufacturing process. 
     The display region  120  and the touch region  140  may be adhered to each other. For example, as shown in  FIG. 1  B, the display region  120  and the touch region  140  may be adhered through adhesion layers  182  and  184 . In this case, a transparent substrate  180  may be provided as an optional structure between the display region  120  and the touch region  140  to adjust a thickness of the display device  100 . It is preferred that the transparent substrate  180  have a light-transmitting property to visible light. The transparent substrate  180  may have flexibility. Note that an edge of the transparent substrate  180  close to the boundary region  160  may be subjected to chamfering so as to have a round shape in order to prevent the base film  102  in the boundary region  160  from being damaged by the transparent substrate  180 . 
     2. Developed Structure 
     A developed state of the display device  100  is shown in  FIG. 2  to explain the structure of the display device  100  in more detail.  FIG. 2  corresponds to a state where the transparent substrate  180  and the adhesion layers  182  and  184  are removed from the display device  100  shown in  FIG. 1  B and the boundary region  160  is flattened. 
     As shown in  FIG. 2 , the base film  102  has the display region  120 , the touch region  140 , and the boundary region  160  between the display region  120  and the touch region  140 . The touch region  140  is provided with the touch portion  142 , while the image-display portion  122  is provided to the display region  120 . In the display device  100  shown in  FIG. 2 , driver circuits  136  are disposed in the display region  120  so as to sandwich the image-display portion  122 . However, the driver circuits  136  are an optional structure, and a driver circuit formed on a different substrate and the like may be additionally provided to the display device  100 . In this case, the driver circuit can be mounted over the wirings  130 , connector  170 , or the like, for example. 
     The wirings  132  electrically connect the second terminals  126  to the touch portion  142 , pass through a region (frame) beside the image-display portion  122 , and extend to the touch region  140  from the display region  120  through the boundary region  160 . The wirings  130  electrically connect the first terminals  124  to the image-display portion  122 . Although not shown, the wirings  132  may be arranged in the boundary region  160  so as to extend in a direction inclined from each of the sides of the image-display portion  122  and the touch portion  142 . 
     Alignment markers  134  may be provided over the base film  102 . The boundary region  160  is folded along an axis  162  so that the alignment markers  134  overlap with each other and the display region  120  and the touch region  140  are adhered to each other, by which the display device  100  shown in  FIG. 1A  to  FIG. 1C  can be obtained. 
     3. Touch Portion 
     An enlarged figure of a partial region  144  of the touch portion  142  is schematically shown in  FIG. 3 . The touch portion  142  is able to detect a touch with a variety of modes. Here, explanation is given using a touch portion of an electrostatic capacity type as an example. 
     The touch portion  142  has a structure in which a plurality of wirings is arranged in a lattice form. Specifically, the touch portion  142  has a plurality of wirings (Tx wirings  146 ) extending in a first direction (e.g., a direction parallel to the first side  128 . See  FIG. 1A ) and a plurality of wirings (Rx wirings  148 ) perpendicularly intersecting with the Tx wirings  146 . Each wiring includes a plurality of substantially square electrodes  150 . For example, in each of the Tx wirings  146 , the plurality of electrodes  150  is arranged in the first direction, and the adjacent electrodes  150  are electrically connected with a Tx bridge electrode (connection electrode)  152 . In  FIG. 3 , an example is shown where the electrodes  150  are formed over the Tx bridge electrodes  152 . The wirings  132  are connected to terminal electrodes of the Tx wirings  146  (the left edge electrodes in  FIG. 3 ) through the wiring connection ports  154 . On the other hand, the Rx wirings  148  have a structure in which the plurality of electrodes  150  and Rx bridge portions  156  connecting the electrodes  150  with each other are integrally formed. The wirings  132  are connected to terminal electrodes (lower edge electrodes in  FIG. 3 ) of the Rx wirings  148  through the wiring connection ports  154 . 
     Each electrode  150  and Rx bridge portion  156  are formed with a conductor transmitting visible light, such as a conductive oxide, for example. On the other hand, it is not necessary for the Tx bridge electrodes  152  to transmit visible light, and the Tx bridge electrodes  152  may be formed with a metal which does not transmit visible light, in addition to a conductive oxide transmitting visible light. 
     4. Image-Display Portion 
     An enlarged figure of a region  138  which is a part of the image-display portion  122  is schematically shown in  FIG. 4 . The image-display portion  122  possesses a plurality of pixels  190 . Display elements such as a light-emitting element or a liquid crystal element can be provided in the plurality of pixels  190 . For example, three adjacent pixels  190  are configured to give red, green, or blue color, by which full-color display can be accomplished. There is also no limitation to an arrangement of the pixels  190 , and a stripe arrangement, a delta arrangement, a Pentile arrangement, and the like may be employed. Compared with the stripe arrangement and the delta arrangement, the Pentile arrangement is effective at increasing apparent resolution with a smaller number of pixels. For example, a part of RGB pixels is arranged in a matrix form with vertical and lateral directions, while the other part of the RGB pixels are arranged alternatively with the part of the pixels in a diagonal direction. The Pentile arrangement is characterized in that the number of sub-pixels is different between RGB. 
     One or a plurality of transistors are provided in each pixel  190 , and a plurality of signal lines  192 ,  194 , and  196  supplying signals to the respective transistors are formed in a lattice form. For example, the signal lines  194 ,  192 , and  196  can respectively supply an image signal, a scanning signal, and a high-potential power-source voltage to each pixel  190 . Although not shown, the image-display portion  122  may have a wiring other than the aforementioned wirings. These wirings are connected to the first terminals  124  through the driver circuits  136  or the wirings  130 . 
     5. Cross-Sectional Structure 
     
         
         5-1. Display Region 
       
    
     A cross-sectional structure of the display device  100  is explained in detail by using  FIG. 5 .  FIG. 5  is a schematic view of a cross-section along a chain line B-B′ of  FIG. 1A . 
     In the display region  120 , the image-display portion  122  is formed over the base film  102 , and each pixel  190  of the image-display portion  122  may include a transistor  200  and a light-emitting element  220  connected to the transistor  200 . An example is shown in  FIG. 5  in which one transistor is formed in each pixel  190 . However, each pixel  190  may possess a plurality of transistors. Moreover, each pixel  190  may contain semiconductor elements other than a transistor, such as a capacitor element. An undercoat  201  may be disposed as an optional structure between the base film  102  and the transistor  200 . 
     The transistor  200  has a semiconductor film  202 , a gate insulating film  204 , a gate electrode  206 , and a pair of source/drain electrodes  208 . A first interlayer film  210  may be arranged over the gate electrode  206 , and the source/drain electrodes  208  are connected to the semiconductor film  202  through opening portions provided in the gate insulating film  204  and the first interlayer film  210 . 
       FIG. 5  is illustrated so that the transistor  200  has a top-gate top-contact type structure. However, the structure of the transistor  200  is not limited, and the transistor  200  may possess a bottom-gate type or a top-gate type. There is also no limitation to a vertical relationship between the semiconductor film  202  and the source/drain electrode  208 . Additionally, a so-called multi-gate type structure in which a plurality of gate electrodes  206  are provided may be employed in the transistor  200 . 
     A second interlayer film  212  may be formed over the transistor  200 , and a leveling film  214  may be formed thereover to absorb depressions and projections caused by the transistor  200  and the like and give a flat surface. 
     The light-emitting element  220  has a first electrode  222 , a second electrode  226 , and an EL layer  224  provided between the first electrode  222  and the second electrode  226 . The first electrode  222  is electrically connected to one of the source/drain electrodes  208  of the transistor  200  through a connection electrode  216 . The first electrode  222  may include a conductive oxide with a light-transmitting property, a metal, or the like. When light obtained from the light-emitting element is extracted through the touch region  140 , a metal such as aluminum or silver or an alloy thereof can be used for the first electrode  222 . In this case, a stacked structure of the aforementioned metal or alloy with a conductive oxide having a light-transmitting property, e.g., a stacked structure in which a metal is sandwiched by a conductive oxide (indium-tin oxide (ITO)/silver/ITO, etc.), may be employed. 
     A partition wall  228  covering an edge portion of the first electrode  222  may be formed in the image-display portion  122 . The partition wall  228  is also called a bank (rib). The partition wall  228  has an opening portion to expose a part of the first electrode  222 , and an edge of the opening portion is preferred to have a tapered shape. A steep edge of the opening portion readily causes a coverage defect of the EL layer  224  and the second electrode  226 . 
     The EL layer  224  is formed so as to cover the first electrode  222  and the partition wall  228 . Note that, in the present specification, the EL layer  224  means all of the layers sandwiched by a pair of electrodes (here, the first electrode  222  and the second electrode  226 ). 
     For the second electrode  226 , it is possible to use a film containing a conductive oxide with a light-transmitting property, such as ITO and indium-zinc oxide (IZO), or a metal film which is formed at a thickness exhibiting a light-transmitting property and which includes silver, magnesium, aluminum, or the like. This structure allows the emission from the EL layer  224  to be extracted through the touch region  140 . 
     The image-display portion  122  may further possess a passivation film  240  over the light-emitting element  220 . The passivation film  240  has a function to prevent moisture from entering the light-emitting element  220  from outside and is preferred to have a high gas-barrier property. The passivation film  240  shown in  FIG. 5  has a three-layer structure and includes a first layer  242  and a third layer  246  containing an inorganic material and a second layer  244  interposed therebetween and containing an organic resin. 
     Note that the leveling film  214  may have, as an optional structure, an opening portion  250  reaching the second interlayer film  212  between the pixel  190  closest to the boundary region  160  and the boundary region  160 . Furthermore, the passivation film  240  may be formed so that the second interlayer film  212  is in contact with the third layer  246  in the opening portion  250 . Introduction of such a structure prevents impurities from being diffused in the leveling film  214  and entering the light-emitting element  220  from the boundary region  160 .
     5-2. Touch Region   

     The touch region  140  has the undercoat  201  extending from the display region  120  through the boundary region  160 , the gate insulating film  204 , and the first interlayer film  210  and possesses the touch portion  142  thereunder. As described above, the touch portion  142  has the Tx wirings  146  including the electrodes  150  and the Tx bridge electrodes  152 , and the Rx wirings  148  including the electrodes  150  and the Rx bridge portions  156 . As described below, the Tx bridge electrodes  152  can be simultaneously formed with the source/drain electrodes  208  or the gate electrode  206  of the transistor  200 . That is, the Tx bridge electrodes  152  are able to exist in the same layer as the source/drain electrodes  208  or the gate electrode  206  of the transistor  200 . Furthermore, the electrodes  150  and the Rx bridge portions  156  can be formed simultaneously with the connection electrode  216 , and therefore, they can exist in the same layer. 
     The second interlayer film  212  extending to the touch region  140  from the display region  120  through the boundary region  160  is provided between the Tx wirings  146  and the Rx wirings  148 , and a capacitor is formed by the Tx wirings  146 , the Rx wirings  148 , and the second interlayer film  212  which is an insulating film. A contact of a finger or a palm with the touch region  140  through the base film  102  causes capacitive coupling and changes a capacitance at the touched positon, by which a touched position can be sensed. 
     The leveling film  214  and the third layer  246  of the passivation film  240  extending from the image-display portion  122  through the boundary region  160  are provided under the touch portion  142 .
     5-3. Boundary Region   

     The base film  102  can be folded in the boundary region  160 . In the boundary region  160 , the undercoat  201 , the gate insulating film  204 , the first interlayer film  210 , the second interlayer film  212 , the leveling film  214 , and the third layer  246  extending from the display region  120  are provided to the base film  102 . These films further extend to the touch region  140 . In the boundary region  160 , the wirings  132  which exist in the same layer as the source/drain electrodes  208  or the gate electrode  206  are disposed between the first interlayer film  210  and the second interlayer film  212 . That is, the wirings  132  extend from the display region  120  to the touch region  140  through the boundary region  160 . 
     It is not always necessary that all of the undercoat  201 , the gate insulating film  204 , the first interlayer film  210 , the second interlayer film  212 , the leveling film  214 , and the third layer  246  are included in the boundary region  160 . It is preferred that at least one of the second interlayer film  212 , the leveling film  214 , and the third layer  246  be formed over the wirings  132  in order to avoid deterioration of the wirings  132 . 
     The display device  100  has the transparent substrate  180  as an optional structure, and the transparent substrate  180  overlaps with the display region  120  and the touch region  140  and is interposed therebetween. The transparent substrate  180  is adhered to the image-display portion  122  and the touch portion  142  with the adhesion layers  182  and  184 , respectively. The transparent substrate  180  may be flexible or has low flexibility similar to a glass substrate. The use of the transparent substrate  180  with low flexibility enables the shape of the display device  100  to be fixed. 
     Although described in detail in the Second Embodiment, each of the layers constructing the boundary region  160  and the touch region  140  is common to the display region  120 . Hence, the image-display portion  122  and the touch portion  142  can be simultaneously formed over one base film  102 . Therefore, it is not necessary to independently manufacture the image-display portion  122  and the touch portion  142 . Additionally, as shown in  FIG. 1A  and  FIG. 1C , signals can be supplied to the image-display portion  122  and the touch portion  142  from an external circuit by using a single connector for the first electrodes  124  and the second electrodes  126 . Thus, it is not necessary to separately connect the connectors to the first electrodes  124  and the second electrodes  126 . As a result, the structure of the display device  100  and the manufacturing process thereof can be simplified, and the display device  100  equipped with the touch portion  142  can be manufactured at low cost. Moreover, the use of the transparent substrate  180  with flexibility allows production of the flexible display device  100  installed with the touch portion  142 . 
     Second Embodiment 
     In the present embodiment, a manufacturing method of the display device  100  described in the First Embodiment is explained by using  FIG. 5  to  FIG. 14 . The contents which are the same as those described in the First Embodiment may be omitted. Note that  FIG. 6A  to  FIG. 14  are schematic cross-sectional views along a chain line C-C′ in  FIG. 2 . 
     As shown in  FIG. 6A , the base film  102  is first formed over a supporting substrate  260 . The supporting substrate  260  has a function to support the semiconductor elements included in the image-display portion  122 , such as the transistor  200 , and the touch portion  142  of the touch region  140 . Thus, it is possible to use a material which has heat resistance to the process temperature of the various elements formed thereover and chemical stability to the chemicals used in the process. Specifically, the supporting substrate  260  may include glass, quartz, plastics, a metal, ceramics, and the like. 
     The base film  102  is an insulating film with flexibility and may contain a material selected from polymer materials exemplified by a polyimide, a polyamide, a polyester, and a polycarbonate. The base film  102  can be prepared by applying a wet-type film-formation method such as a printing method, an ink-jet method, a spin-coating method, and a dip-coating method or a lamination method. 
     Next, as shown in  FIG. 6B , the undercoat  201  is formed over the base film  102 . The undercoat  201  is a film functioning to prevent diffusion of impurities from the supporting substrate  206  and the base film  102  to the transistor  200  and the like and may contain an inorganic insulator such as silicon nitride, silicon oxide, silicon nitride oxide, and silicon oxynitride. The undercoat  201  can be formed with a chemical vapor deposition method (CVD method), a sputtering method, a lamination method, and the like so as to have a single-layer or stacked-layer structure. Note that, when an impurity concentration of the base film  102  is low, the undercoat  201  may not be formed or be formed to only partly cover the base film  102 . 
     Next, the semiconductor film  202  is formed. The semiconductor film  202  may contain a Group  14  element such as silicon. Alternatively, the semiconductor film  202  may include an oxide semiconductor. As an oxide semiconductor, Group  13  elements such as indium and gallium are represented, and a mixed oxide of indium and gallium (IGO) is exemplified. When an oxide semiconductor is used, the semiconductor film  202  may further contain a Group  12  element, and a mixed oxide including indium, gallium, and zinc (IGZO) is represented as an example. Crystallinity of the semiconductor film  202  is not limited, and the semiconductor film  202  may be single crystalline, polycrystalline, microcrystalline, or amorphous. 
     When the semiconductor film  202  includes silicon, the semiconductor film  202  may be formed with a CVD method by using a silane gas and the like as a raw material. Crystallization may be conducted by performing a heat treatment or applying light such as a laser on the obtained amorphous silicon. When the semiconductor film  202  includes an oxide semiconductor, the semiconductor film  202  can be formed by utilizing a sputtering method. 
     Next, the gate insulating film  204  is formed so as to cover the semiconductor film  202 . The gate insulating film  204  may have a single-layer or stacked-layer structure and may be formed with a method similar to that of the undercoat  201 . 
     Next, the gate electrode  206  is formed over the gate insulating film  204  by applying a sputtering method or a CVD method ( FIG. 7A ). The gate electrode  206  can be formed with a metal such as titanium, aluminum, copper, molybdenum, tungsten, and tantalum or an alloy thereof so as to have a single-layer or stacked-layer structure. For example, a structure may be employed in which a metal with a high conductivity, such as aluminum and copper, is sandwiched by a metal with a relatively high melting point, such as titanium, tungsten, and molybdenum. 
     Next, the first interlayer film  210  is formed over the gate electrode  206  ( FIG. 7B ). The first interlayer film  210  may have a single-layer or a stacked-layer structure and can be formed with a method similar to that of the undercoat  201 . 
     Next, etching is carried out on the first interlayer film  210  and the gate insulating film  204  to form the opening portions reaching the semiconductor film  202  ( FIG. 8A ). The opening portions may be formed by performing plasma etching in a gas including a fluorine-containing hydrocarbon, for example. 
     Next, a metal film is formed to cover the opening portions and is processed with etching to form the wirings  132  and the Tx bridge electrodes  152  in addition to the source/drain electrodes  208  ( FIG. 8B ). Therefore, in the display device  100 , the source/drain electrodes  208 , the wirings  132 , and the Tx bridge electrodes  152  exist in the same layer. The metal film may possess a similar structure as the gate electrode  206  and may be formed with a similar method as that of the gate electrode  206 . Although not shown, the wirings  132  and the Tx bridge electrodes  152  may be prepared simultaneously when the gate electrode  206  is formed. 
     Next, as shown in  FIG. 9A , the second interlayer film  212  is formed over the source/drain electrodes  208 , the wirings  132 , and the Tx bridge electrodes  152 . The second interlayer film  212  may be formed similar to the undercoat  201 . Furthermore, the second interlayer film  212  is subjected to etching to form opening portions reaching the source/drain electrodes  208 , the wirings  132 , and the Tx bridge electrodes  152 . These opening portions may be also prepared with dry etching such as the aforementioned plasma etching. 
     Next, a conductive film is formed to cover the opening portions and processed with etching to form the connection electrode  216 , the electrodes  150 , and the Rx bridge portions  156  ( FIG. 9B ). The conductive film can be formed with a sputtering method by using a conductor transmitting visible light, such as ITO and IZO. Alternatively, the conducting film may be formed with a sol-gel method by using an alkoxide of a corresponding metal. Through the aforementioned process, the touch portion  142  is fabricated. Here, in the present specification and claims, one of the main surfaces of the touch portion  142  opposing each other, which is closer to the base film  102  is called a lower surface or a back surface, and the other of the main surfaces which is farther from the base film  102  is called an upper surface or a front surface. 
     Next, the leveling film  214  is formed to cover the connection electrode  216 , the electrodes  150 , and the Rx bridge portions  156  ( FIG. 10A ). The leveling film  214  has a function to absorb depressions and projections caused by the transistor  200  and the touch portion  142  including the Rx bridge portions  156  and the electrodes  150  to provide a flat surface. The leveling film  214  can be formed with an organic insulator. As an organic insulator, a polymer material such as an epoxy resin, an acrylic resin, a polyimide, a polyamide, a polyester, a polycarbonate, and a polysiloxane is represented, and the leveling film  214  can be formed with the aforementioned wet-type film-formation method. The leveling film  214  may have a stacked structure including a layer containing the aforementioned organic insulator and a layer containing an inorganic insulator. In this case, an inorganic insulator including silicon, such as silicon oxide, silicon nitride, silicon nitride oxide, and silicon oxynitride, is represented as an inorganic insulator, and the films including these inorganic insulators can be prepared with a sputtering method or a CVD method. 
     Next, etching is performed on the leveling film  214  to form an opening portion reaching the connection electrode  216 . After that, the first electrode  222  of the light-emitting element  220  is formed over the leveling film  214  with a sputtering method and the like to cover the opening portion ( FIG. 10B ). 
     Next, the partition wall  228  is formed so as to cover the edge portion of the first electrode  222  ( FIG. 11A ). With the partition wall  228 , a step caused by the first electrode  222  and the like is absorbed, and the first electrodes  222  of the adjacent pixels  190  can be electrically insulated from each other. The partition wall  228  may be formed with a wet-type film-formation method by using a material applicable in the leveling film  214 , such as an epoxy resin and an acrylic resin. 
     Next, the EL layer  224  and the second electrode  226  of the light-emitting element  220  are formed so as to cover the first electrode  222  and the partition wall  228  ( FIG. 11  B). The EL layer  224  may be formed with a single layer or a plurality of layers. For example, the EL layer  224  can be formed by appropriately combining a carrier-injection layer, a carrier-transporting layer, an emission layer, a carrier-blocking layer, an exciton-blocking layer, and the like. Additionally, the EL layer  224  may be different between the adjacent pixels  190 . For example, the EL layer  224  may be fabricated so that the emission layer is different but other layers have the same structure between the adjacent pixels  190 . On the contrary, the same EL layer  224  may be used in all of the pixels  190 . In this case, the EL layer  224  giving white emission is formed so as to be shared by the adjacent pixels  190 , and a color filter is used to select a wavelength of light extracted from each pixel  190 , for example. 
     The second electrode  226  can be formed with a similar method as that of the first electrode  222  by using a metal, a conductive oxide having a light-transmitting property, or the like. 
     Next, the passivation film  240  is formed. For example, the first layer  242  is first prepared over the second electrode  226  as shown in  FIG. 12A . The first layer  242  may contain an inorganic material such as silicon nitride, silicon oxide, silicon nitride oxide, or silicon oxynitride and can be formed with a similar method as that of the undercoat  201 . The first layer  242  may be selectively formed over the light-emitting element  220  as shown in  FIG. 12A  or formed in the boundary region  160  and the touch region  140 . 
     Next, the second layer  244  is formed ( FIG. 12A ). The second layer  244  may contain an organic resin including an acrylic resin, a polysiloxane, a polyimide, and a polyester. Furthermore, the second layer  244  may be prepared at a thickness to absorb depressions and projections caused by the partition wall  228  providing a flat surface. The second layer  244  may also be formed in a region where the boundary region  160  and the touch region  140  are formed. The second layer  244  can be formed with the aforementioned wet-type film-formation method. Alternatively, the second layer  244  may be formed by atomizing or vaporizing oligomers serving as a raw material of the aforementioned polymer materials under a reduced pressure, spraying the first layer  244  with the oligomers, and then polymerizing the oligomers. 
     Next, in the region between the pixel  190  of the display region  120  closest to the boundary region  160  and the boundary region  160 , the opening portion is formed in the leveling film  214  ( FIG. 12B ). The opening portion may be prepared with the aforementioned dry etching and the like. 
     After that, the third layer  246  is formed ( FIG. 13A ). The third layer  246  may have a similar structure and can be prepared with a similar method as those of the first layer  242 . The third layer  242  may be formed not only over the opening portion provided in the leveling film  214  and the light-emitting element  220  but also over the boundary region  160  and the touch region  140 . The third layer  246  is in contact with the second interlayer film  212  in the opening portion. This structure disconnects the leveling film  214 . With this structure, it is possible to prevent diffusion of impurities from the boundary region  160  to the display region  120  through the leveling film  214 , thereby improving reliability of the light-emitting element  220 . 
     After that, the supporting substrate  260  is separated. For example, light such as a laser is applied from a side of the supporting substrate  260  to decrease adhesion between the supporting substrate  260  and the base film  102 . Simultaneously, the transparent substrate  180  may be adhered to the touch region  140  by using the adhesion layer  182  ( FIG. 13B ). As the adhesion layer  182 , a photo-curable resin, a thermosetting resin, and the like can be used. As the transparent substrate  180 , a substrate containing a material transmitting visible light, such as a glass substrate and a plastic substrate, can be employed. 
     After adhering the transparent substrate  180  to the touch region  140 , the adhesion layer  184  is further applied on the transparent substrate  180  or the display region  120 , and the transparent substrate  180  is transferred as indicated by a curved arrow in  FIG. 14 . Namely, the base film  102  is folded so that a back surface of the touch portion  142  opposes the image-display portion  122  through the touch portion  142 . Pealing occurs at an interface with reduced adhesion (a straight arrow in  FIG. 14 ) between the supporting substrate  260  and the base film  102 . Adhesion of the transparent substrate  180  to the display region  120  via the adhesion layer  184  results in the formation of the display device  100  having the structure shown in  FIG. 5 . 
     As described above, application of the manufacturing method of the present embodiment enables the simultaneous formation of the display region  120  and the touch region  140 . Therefore, the process of the display device  100  can be simplified. As a result, the display device  100  installed with the touch portion  142  over the image-display portion  122  can be manufactured at low cost. 
     Third Embodiment 
     In the present embodiment, display devices different in structure from the display device  100  shown in the First Embodiment are explained by using  FIG. 15A  to  FIG. 17 . Contents which are the same as those described in the First and Second Embodiments may be omitted. FIG.  15 A to  FIG. 17  are schematic cross-sectional views along a chain line B-B′ in  FIG. 1A . 
     A display device  270  shown in  FIG. 15A  is different from the display device  100  shown in the First Embodiment in that the transparent substrate  180  is not included. For example, when the base film  102  is thin or flexibility thereof is high, the boundary region  160  can be largely folded. Thus, the display region  120  and the touch region  140  can be tightly adhered with only the adhesion layer  182  even though the transparent substrate  180  is not used. This structure allows the production of a flexible display device installed with a touch panel. 
     Note that, similar to the display device  272  shown in  FIG. 15B , the adhesion layer  182  may be provided so as to fill the entire region enclosed by the display region  120 , the touch region  140 , and the boundary region  160  by which strength of the boundary region  160  and a periphery thereof can be increased. 
     A display device  274  shown in  FIG. 16  is different from the display device  100  shown in the First Embodiment in that the third layer  246  of the passivation film  240  is selectively provided in the display region  120  and is not disposed in the boundary region  160  and the touch region  140 . As described in the Second Embodiment, since the third layer  246  can include an inorganic material, the third layer  246  is more rigid than the second layer  244  and the like which can include a polymer material. Therefore, the selective formation of the third layer  246  in the display region  120  offers high flexibility to the boundary region  160 , allowing the boundary region  160  to be readily folded. Additionally, an inorganic material usable in the third layer  246  has a higher refractive index compared with a polymer material. Hence, visibility of the image-display portion  122  can be improved without providing the third layer  246  in the touch region  140 . Moreover, the wirings  132  can be arranged close to a center line (a line passing through a center between the bottom surface and the upper surface of the boundary region  160 ) in the boundary region  160 . 
     A display device  276  shown in  FIG. 17  is different in structure of the Tx wiring and the Rx wiring of the touch portion  142  from the display device  274  shown in  FIG. 16 . Specifically, the electrodes  150  included in the Tx wirings  146  and the Rx wirings  148  and the Rx bridge portions  156  included in the Rx wirings  148  (see  FIG. 3 ) exist in the same layer as the connection electrode  216  of the display region  120 . On the other hand, a part of the Tx bridge electrodes  152  is located over the leveling film  214 . Furthermore, the Tx bridge electrodes  152  contain the layer included in the first electrode  222  of the light-emitting element  220 . Hence, the Tx bridge electrodes  152  exist in the same layer as the first electrode  222 . Specifically, as shown in an enlarged figure in  FIG. 17 , the first electrode  222  possesses a first layer  280 , a second layer  282 , and a third layer  284 , where the first layer  280  and the third layer  284  include a conductive oxide with a light-transmitting property and the second layer  282  includes a metal with a high reflectance, such as silver or aluminum. The Tx bridge electrodes  152  contain a metal included in the second layer  282  and exist in the same layer as the second layer  282 . 
     With this structure, the electrodes  150  are arranged at a position farther from the display region  120 , that is, a position closer to a user than the Tx bridge electrodes  152 . Therefore, visibility of the image-display portion  122  is increased, and an image with higher quality is provided. 
     Fourth Embodiment 
     In this embodiment, display devices different in structure from the display devices  270 ,  272 ,  274 , and  276  of the First Embodiment are explained by using  FIG. 18  to  FIG. 23 . The structures which are the same as those of the First to Third Embodiments may be omitted. Note that, for clarity, the base film  102  of the touch region  140  provided over the display region  120  is not illustrated in  FIG. 18 ,  FIG. 20 , and  FIG. 22 . 
     A top view of a display device  300  which is a display device of the present embodiment is shown in  FIG. 18 . As shown in  FIG. 18 , the base film  102  possesses the display region  120 , the touch region  140 , and the boundary region  160  between the display region  120  and the touch region  140 . The touch region  140  is located over and overlaps with the display region  120 . The display device  300  is different in structure of the boundary region  160  from the display device  100 . 
     Specifically, as shown in  FIG. 18 , the boundary region  160  has a portion (protruding portion)  302  protruding in a direction parallel to an upper surface or a lower surface of the base film  102  from a region where the image-display portion  122  and the touch portion  142  overlap with each other. A width of the protruding portion  302  is smaller than a width (a width in a direction of an axis  162  in  FIG. 19 ) of the base film  102  in the display region  120  and the touch region  140 . The wirings  132  connecting the second terminals  126  to the touch portion  142  extend to the touch region  140  through the protruding portion  302  of the boundary region  160 . Note that, in  FIG. 18 , the protruding portion  302  is located at a center of one side of the display device  300 . However, the protruding portion  302  may be arranged at a position shifted in any direction along this side. 
     A shape and arrangement of the protruding portion  302  is not limited to those of the display device  300 . For example, the boundary region  160  may have two protruding portions  302  as demonstrated by the display device  320  shown in  FIG. 20 . Alternatively, similar to a display device  330  shown in  FIG. 22 , two protruding portions  302  may be provided at edge portions of the base film  102  in the boundary region  160 . In these display devices  320  and  330 , the wirings  132  connecting the second terminals  126  to the touch portion  142  extend to the touch region  140  through the two protruding portions  302  in the boundary region  160 . In this case, the number of the wirings  132  arranged in the two protruding portions  302  may be different from each other. Additionally, the widths of the two protruding portions  302  may be different from each other. 
     As shown in  FIG. 19 , the display device  300  having such a structure can be fabricated by providing two slits  304  to the base film  102  in the boundary region  160  to reduce a width of a part of the base film  102  and then folding the base film  102  along the axis  162  passing through the region with the small width. Similarly, as shown in  FIG. 21 , the display device  320  can be fabricated by providing two slits  304  and an opening portion  308  therebetween to reduce the width of a part of the base film  102  and then folding the base film  102  at this part along the axis  162 . A shown in  FIG. 23 , the display device  330  can be fabricated by providing the boundary region  160  with an opening portion  308  having a length which is equal to or longer than the widths of the image-display portion  122  and the touch portion  142  and then folding the base film  102  at this part along the axis  162 . 
     Alignment markers  134  are formed in the display region  120  and the touch region  140 , and the base film  102  is folded so that the alignment markers  134  overlap with each other, by which the touch region  140  can be stacked over the display region  120  at high reproducibility and accuracy. 
     When the display device  300  or  320  is fabricated, a tip portion of the slit  304 , that is, a corner  306  of the slit  304  preferably has a curved shape ( FIG. 19 ,  FIG. 21 ). Similarly, a corner  310  of the opening portion  308  formed when the display device  320  or  330  is fabricated preferably has a curved shape ( FIG. 21 ,  FIG. 23 ). The formation of such a curved shape at the tip portion of the slit  304  and the corner  310  of the opening portion  308  prevents damage to the base film  102  when the base film  102  is folded, by which disconnection of the display region  120  from the touch region  140  can be prevented. 
     In the display devices  300 ,  320 , and  330 , since the width of the folded portion in the boundary region  160  is small, a force which is applied when the folded base film  102  recovers to its original shape (restoration force) can be reduced, by which the folding process can be facilitated and the shapes of the display devices  300 ,  320 , and  330  can be stably maintained. 
     Fifth Embodiment 
     In this embodiment, display devices different in structure from the display devices of the First to Fourth Embodiments are explained by using  FIG. 24  to  FIG. 43 . The structures which are the same as those of the First to Fourth Embodiments may be omitted. Note that, for clarity, the base film  102  of the touch region  140  provided over the display region  120  is not illustrated in  FIG. 24 ,  FIG. 28 ,  FIG. 32 ,  FIG. 36 ,  FIG. 38 ,  FIG. 40 , and  FIG. 42 . 
     A top view of a display device  350  which is a display device of the present embodiment is shown in  FIG. 24 , and cross-sectional views along chain lines D-D′, E-E′, and F-F′ of  FIG. 24  are illustrated in  FIG. 25A ,  FIG. 25B , and  FIG. 25C , respectively. As shown in  FIG. 24  and  FIG. 25A  to  FIG. 25C , the base film  102  has the display region  120 , the touch region  140 , and the boundary region  160  between the display region  120  and the touch region  140 . The touch region  140  is located over and overlaps with the display region  120 . The display device  350  is different from the display device  100  in position and structure of the boundary region  160  and in vertical relationship between the touch portion  142  and the base film  102 . 
     Specifically, as shown in  FIG. 24 , the boundary region has the protruding portion  302 . The protruding portion  302  protrudes in a direction parallel to the first side  128  from a region where the display region  120  and the touch region  140  overlap with each other. The wirings  132  connecting the second terminals  126  to the touch portion  142  extend to the touch region  140  from the display region  120  through the protruding portion  302 . Additionally, the protruding portion  302  has a three-folded structure. For example, as shown in  FIG. 25A , the base film  102  has a three-folded structure having two bent portions, and the wirings  132  are folded according to the folded structure of the base film  102 . 
     On the other hand, as shown in  FIG. 25B  and  FIG. 25C , although the touch region  140  is located over and overlaps with the display region  120 , the touch portion  142  is located over the base film  102  of the touch region  140 . Hence, the transparent substrate  180  is not directly adhered to the touch portion  142  but adhered to the base film  102  in the touch region  140  with the adhesion layer  184 . Therefore, the base film  102  has a three-layer structure in the protruding portion  302  but has a two-layer structure in the region where the display region  120  overlaps with the touch region  140   
     The display device  350  having such a structure can be fabricated by the following method. For example, as shown in  FIG. 26 , the image-display portion  122  and the touch portion  142  are respectively formed in the display region  120  and the touch region  140  over the base film  102 . The boundary region  160  is not arranged to be sandwiched between the display region  120  and the touch region  140 , but arranged so as to be in contact with side surfaces of the display region  120  and the touch region  140 , which are not sandwiched by the display region  120  and the touch region  140 . Here, the side surfaces of the display region  120  and the touch region  140 , which are in contact with the boundary region  160 , are perpendicular to the first side  128  of the image-display portion  122 . A length Lb (a length in a direction perpendicular to the first side  128 ) of the boundary region  160  is ½ or more of a summation of a length Ld of the side surface of the display region  120  and a length Lt of the side surface of the touch region  140 . Moreover, the opening portion  308  in contact with the side surfaces of the display region  120  and the touch region  140  is provided in the boundary region  160 . Similar to the Fourth Embodiment, it is preferred that the corner of the opening portion  308  have a curved shape. 
     After that, the base film  102  is folded so that the front surface of the touch portion  142  overlaps with the image-display portion  122  with the touch portion  142  interposed therebetween. Specifically, as indicated by an arrow in the drawing, the boundary region  160  is folded twice along axes  166  and  168 . Here, the axes  166  and  168  each intersect the opening portion  308 , and the axis  166  is closer to the touch region  140  than the other. More specifically, as shown in  FIG. 27 , the boundary region  160  is folded so that a portion of the boundary region  160  further up than the axis  166  covers a portion lower than the axis  166  and that a portion of the boundary region  166  between the axes  166  and  168  covers a portion of the boundary region  160  lower than the axis  168 . In this case, the touch region  140  is placed over the display region  120  so that the alignment markers in the display region  120  and the touch region  140  overlap with each other, thereby giving the display device  350 . 
     Note that, in  FIG. 26  and  FIG. 27 , a case is illustrated where the display device  350  is fabricated from a state in which the touch region  140  is positioned over the display region  120  in the developed state. 
     However, the display device  350  may be fabricated from a state where the display region  120  is positioned over the touch region  140 . In this case, the boundary region  160  is folded so that the portion of the boundary region  160  lower than the axis  168  covers a portion further up than the axis  168  and that the portion of the boundary region  166  between the axes  166  and  168  covers the portion of the boundary region  166  further up than the axis  166 . 
     A display device of the present embodiment may be a display device  360  having a structure shown in  FIG. 28 ,  FIG. 29A ,  FIG. 29B , and  FIG. 29C .  FIG. 29A ,  FIG. 29B , and  FIG. 29C  are schematic cross-sectional views along chain lines G-G′, H-H′, and I-I′ of  FIG. 28 , respectively. The display device  360  is different from the display device  350  in the folding mode of the boundary region  160 . More specifically, the boundary region  160  is folded along the axis  166  so that the portion of the boundary region  160  further up than the axis  166  in  FIG. 30  is arranged under the portion lower than the axis  168  and that the touch portion  142  is located under the base film  102  of the touch region  140  ( FIG. 31 ). Furthermore, as indicated by an arrow in  FIG. 31 , the boundary region  160  is folded along the axes  166  and  168 , and the touch region  140  is arranged over the display region  120  so that the alignment markers  134  in the touch region  140  match the alignment markers  134  in the display region  120 . 
     Such deformation allows production of the display device  360 . Hence, as shown in  FIG. 29C , a part of the boundary region  160  is positioned under the display region  120 . 
     Alternatively, a display device of the present embodiment may be a display device  370  having a structure shown in  FIG. 32 ,  FIG. 33A ,  FIG. 33B , and  FIG. 33C .  FIG. 33A ,  FIG. 33B , and  FIG. 33C  are schematic cross-sectional views along chain lines J-J′, K-K′, and L-L′ of  FIG. 32 , respectively. The display device  370  is different from the display devices  350  and  360  in folding mode of the boundary region  160 . More specifically, as shown in  FIG. 34  and  FIG. 35 , the boundary region  160  is folded along the axis  168 , the portion of the boundary region  160  further up than the axis  168  is lifted up, and the touch portion  142  is arranged so as to face the image-display portion  122 . After that, the boundary region  160  is further folded along the axis  166 , and the touch region  140  is arranged over the display region  120  so that the alignment markers in the touch region  140  cover the alignment markers  134  in the display region  120 . 
     Such deformation allows production of the display device  370 . Hence, as shown in  FIG. 33C , a part of the boundary region  160  is positioned over the touch region  140 . 
     Alternatively, a display device of the present embodiment may be a display device  380  having a structure shown in  FIG. 36 ,  FIG. 37A , and  FIG. 37B .  FIG. 37A  is a cross-sectional view along a chain line M-M′ of  FIG. 36 , and  FIG. 37B  is a side view observed from a M side of the chain line M-M′. That is, the boundary region  160  may possess an overlapping portion  312  which is positioned under the display region  120  and overlaps with the display region  120  and the touch region  140  and the protruding portion  302  protruding in a direction parallel to the first side  128  from a region in which the display region  120  and the touch region  140  overlap with each other. The protruding portion  302  connects the overlapping portion  312  to the display region  120  and the overlapping portion  312  to the touch region  140 . Wirings  132  extend from the display region  120  to the touch region  140  through the protruding portion  302 , the overlapping portion  312 , and the protruding portion  302  in this order. Therefore, the wirings  132  extend on a side surface of the protruding portion  302  from under the display region  120  to the touch region  140  ( FIG. 37B ). 
     Such a structure can be formed by folding the protruding portion  302  of the display device  350  shown in  FIG. 24  along an axis  164  and placing a part of the protruding portion  302  under the display region  120 . With this structure, an area (an area of a frame) other than that of the display region  120  or the touch region  140  can be reduced. 
     Furthermore, another mode of a display device of the present embodiment is a display device  390  shown in  FIG. 38 . The display device  390  is different from the display device  350  in position of the protruding portion  302  originating from the boundary region  160 . Namely, the protruding portion  302  of the display device  390  is formed on side surfaces of the display region  120  and the touch region  140  which are close to the first terminals  124  and the second terminals  126 . 
     The display device  390  having such a structure can be fabricated by a method similar to that of the display device  350 . A difference from the fabrication method of the display device  350  is that the boundary region  160  is formed so as to extend to the side surface of the touch region  140  close to the first terminals  124  and the second terminals  126  from the side surface of the display region  120  close to the first terminals  124  and the second terminals  126  as shown in  FIG. 39 . Similar to the display device  350 , the display device  390  can be formed by folding the boundary region  160  along the axes  166  and  168  according to a direction of an arrow and placing the touch region  140  over the display region  120  so that the alignment markers  134  in the touch region  140  and the display region  120  overlap with each other. 
     In the display device  390 , the wirings  132  extending from the second terminals  126  to the touch portion  142  pass through the boundary region  160  but are not arranged in the frame beside the image-display portion  122 . Hence, the wirings  132  are arranged apart from the image-display portion  122  by which influence of a variety of signals supplied to the image-display portion  122  on the operation of the touch portion  142  can be suppressed. 
     The protruding portion  302  originating from the boundary region  160  is not limited to one. For example, as demonstrated by a display device  400  shown in  FIG. 40 , the protruding portions  302  may be disposed on both sides of the display device so as to sandwich the image-display portion  122  and the touch portion  142 . Similar to the display device  390 , the display device  400  can be fabricated by folding the boundary region  160  along the axes  166  and  168  according to a direction of an arrow and placing the touch region  140  over the display region  120  so that the alignment markers  134  of the touch region  140  and the display region  120  overlap with each other as shown in  FIG. 41 . 
     In the display device  400 , the wirings  132  extending from the second terminals  126  are connected to the touch portion  142  via one of the two boundary regions  160 . Therefore, widths of the left and right boundary regions  160  can be reduced. 
     It is not always necessary to arrange the protruding portion  302  on the side surface of the display device, and the protruding portion  302  may be formed on an upper portion of the image-display portion  122  or the touch portion  142  as demonstrated by a display device  410  shown in  FIG. 42 . That is, the protruding portion  302  may be formed on a side surface opposing the first side  128  with the image-display portion  122  interposed therebetween. In this case, the protruding portion  302  protrudes in a direction perpendicular to the first side  128 . Moreover, the protruding portion  302  may be disposed at a position shifted in a left or right direction. 
     As shown in  FIG. 43 , the display device  410  can be fabricated by respectively arranging the display region  120  and the touch region  140  on left and right sides and folding the base film  102  having the boundary region  160  connected to upper sides thereof along the axes  166  and  168  so that the touch region  140  covers the display region  120 . A length Lb of the boundary region  160  may be ½ or more of a summation of a width Wd of the display region  120  and a width Wt of the touch region  140 . In  FIG. 43 , an example is shown in which the display region  120  is positioned on a right side with respect to the touch region  140 . However, the display region  120  may be disposed on a left side with respect to the touch region  140 . 
     As described above, the display devices  350 ,  360 ,  370 ,  380 ,  390 ,  400 , and  410  described in this embodiment are different from the display devices  100 ,  270 ,  272 ,  274 , and  276  in that the touch portion  142  is formed over the base film  102  in the touch region  140 . That is, the touch portion  142  is arranged on a position closer to a user. Hence, it is possible to sense a touch by a user at a higher sensitivity. 
     Sixth Embodiment 
     In the present embodiment, display devices with a structure different from those of the display devices described in the First, and Third to Fifth Embodiments are explained by using  FIG. 44A  to  FIG. 50 . The structures which are the same as those of the First to Fifth Embodiments may be omitted. Note that the base film  102  of the touch region  140  provided over the display region  120  is not illustrated in  FIG. 44A ,  FIG. 44B ,  FIG. 47A , and  FIG. 47B  for clarity. 
     Top views of display devices  420  and  430  of the present embodiment are shown in  FIG. 44A  and  FIG. 44B , respectively. The display device  420  and  430  are different from the display devices described in the First and Third to Fifth Embodiments in that a part of or the entire boundary portion  160  exists in a region in which the display region  120  overlaps with the touch region  140 . In the display device  420 , a part of the boundary region  160  exists in the region where the display region  120  overlaps with the touch region  140 , and another part thereof sticks out of this region to form the protruding portion  302 . On the other hand, in the display device  430 , the entire boundary region  160  exists in the region where the display region  120  overlaps with the touch region  140 . 
     Schematic views of cross-sections along chain lines N-N′, O-O′, and P-P′ in  FIG. 44B  are shown in  FIG. 45A ,  FIG. 45B , and  FIG. 45C , respectively. As shown in  FIG. 45A  and  FIG. 45C , the base film  102  has a three-folded structure, and the boundary region  160  exists in the region where the display region  120  overlaps with the touch region  140 . As shown in  FIG. 45B , the touch portion  142  is formed over the base film  102  in the touch region  140 . Hence, the transparent substrate  180  is not in contact with the touch portion  142  but adhered to the base film  102  of the touch region  140  through the adhesion layer  184 . In such a structure, the touch portion  142  is arranged at a position closer to a user. Hence, it is possible to sense a touch by a user at a higher sensitivity. 
     The display device  430  can be fabricated by a method shown in  FIG. 46 . That is, the slit  304  in contact with the display region  120  and the touch region  140  is provided to the base film  102  in the boundary region  160  between the display region  120  and the touch region  140 . A length Ls of the slit  304  may be equal to or longer than a summation of a width of the touch portion  142  or the image-display portion  122  and a width Lf of the frame. Therefore, a width of the boundary region  160  is equal to or smaller than that of the frame. A width Ws of the slit  304  may be at least equal to or larger than a length Lt of the touch region  140 . After that, the boundary region  160  is folded along the axis  166  and an axis  169  overlapping with a side of the display region  120  so that the touch region  140  is positioned over the display region  120 , the front surface of the touch portion  142  overlaps with the image-display portion  122  with the touch portion  142  sandwiched therebetween, and the alignment markers  134  in the touch region  140  match the alignment markers  134  in the display region  120 , thereby giving the display device  430 . Note that the display device  420  can be obtained when the display region  160  is folded along the axis  168  which is closer to the touch portion  142  than the axis  169 . 
     In the display devices  420  and  430 , the first terminals  124  and the second terminals  126  are each formed over the base film  102  in the display region  120 . However, the present embodiment is not limited to such a structure. For example, as demonstrated by display devices  450  and  460  shown in  FIG. 47A  and  FIG. 47B , the first terminals  124  may be formed over the base film  102  in the display region  120 , while the second terminals  126  may be formed over the base film  102  in the touch region  140 . Additionally, the wirings  132  are provided over the base film  102  in the touch region  140 . In this case, it is preferred that a tab  314  be provided to the base film  102  in the touch region  140  and the second terminals  126  be formed thereover. This structure allows both first terminals  124  and second terminals  126  to be arranged at a vicinity of the first side  128  and the first terminals  124  to be exposed from the base film  102  of the touch region  140 . 
     Similar to the display devices  420  and  430 , the display devices  450  and  460  can be fabricated with a method shown in  FIG. 48 . The display device  460  is obtained by folding along the axes  166  and  169 , whereas the display device  450  is obtained by folding along the axes  166  and  168 . 
     As shown  FIG. 48 , it is not necessary to arrange the wirings  132  in the boundary region  160  in the display device  450  and  460 . Hence, a width of the boundary region  160  can be reduced. As a result, a width of the frame can be decreased. 
     When the display device  420 ,  430 ,  450 , or  460  is mass-produced, a plurality of display devices is fabricated over a large-size mother glass and separated from each other. For example, an arrangement example in the case where the display devices  430  are mass-produced is shown in  FIG. 49 . As shown in  FIG. 49 , the display devices  430  which are in the developed state prior to folding the boundary region  160  are regularly arranged. In this case, one of a pair of the display devices  430  may be placed upside down, and the display region  120  thereof is inserted to the slit  304  (see  FIG. 46 ) of the other display devices  430  to form a substantially rectangular region  472 . Arrangement of the rectangular regions  472  on the mother glass  470  enables the display devices  430  in the developed state to be more densely arranged since the mother glass  470  is normally rectangular. Hence, manufacturing cost of the display device  430  can be decreased. 
     Alternatively, the rectangular region  472  may be formed by combining two display devices  430  with symmetric structures. In  FIG. 50 , the touch region  140  of one of two display devices  430  is inserted to the slit  304  of the other display device  430 . 
     The aforementioned modes described as the embodiments of the present invention can be implemented by appropriately combining with each other as long as no contradiction is caused. Furthermore, any mode which is realized by persons ordinarily skilled in the art through the appropriate addition, deletion, or design change of elements or through the addition, deletion, or condition change of a process is included in the scope of the present invention as long as they possess the concept of the present invention. 
     In the specification, although the cases of the organic EL display device are exemplified, the embodiments can be applied to any kind of display devices of the flat panel type such as other self-emission type display devices, liquid crystal display devices, and electronic paper type display device having electrophoretic elements and the like. In addition, it is apparent that the size of the display device is not limited, and the embodiment can be applied to display devices having any size from medium to large. 
     It is properly understood that another effect different from that provided by the modes of the aforementioned embodiments is achieved by the present invention if the effect is obvious from the description in the specification or readily conceived by persons ordinarily skilled in the art.