Abstract:
An input device, a display device and an electronic apparatus are disclosed. The input device includes a substrate with a main surface. First and second detection electrodes, first and second connecting electrodes, first and second insulating layer are disposed on the main surface. The first and second detection electrodes are aligned in first and second directions, respectively. The first connecting electrodes each connect two of the neighboring first detection electrodes. The second connecting electrodes each connect two of the neighboring second detection electrodes. The first insulating layer is located on the first connecting electrode. The second insulating layer is disposed between the main surface of the substrate, and at least one of the first and second detection electrodes and the first connecting electrodes. The second insulating layer separates the main surface from the at least one of the first and second detection electrodes and the first connecting electrodes.

Description:
TECHNICAL FIELD 
     The present invention relates to an input device, a display device, and an electronic apparatus. 
     BACKGROUND ART 
     Capacitive touch panels with which an input position is detected by a change in capacitance between a finger and a detection electrode are known as the input devices (for example, refer to PTL 1 and PTL 2), for example. 
     An input device of this type includes a substrate having a main surface, first detection electrodes disposed on the main surface of the substrate and aligned in a first direction, and second detection electrodes disposed on the main surface of the substrate and aligned in a second direction. The input device also includes a first connecting electrode that is disposed on the main surface of the substrate and connects the first detection electrodes adjacent to each other, an insulating layer disposed on the main surface of the substrate and positioned on the first connecting electrode, and a second connecting electrode that is disposed on the insulating layer and connects the second detection electrodes adjacent to each other. 
     However, there was a possibility that the strength of the substrate of such an input device would be degraded since the first detection electrodes, the second detection electrodes, and the first connecting electrode are directly formed on the main surface of the substrate. 
     [PTL 1] Japanese Unexamined Patent Application Publication No. 2008-97283 
     [PTL 2] Japanese Unexamined Patent Application Publication No. 2008-310551 
     SUMMARY OF INVENTION 
     The present invention has been made to address the aforementioned issue, and an object thereof is related to an input device, a display device, and an electronic apparatus with which the possibility of the decrease in strength of the substrate can be lowered. 
     An embodiment of an input device according to the present invention includes: a substrate including a main surface; first detection electrodes provided on the main surface of the substrate and aligned in a first direction; second detection electrodes provided on the main surface of the substrate and aligned in a second direction; first connecting electrodes provided on the main surface of the substrate and connecting the first detection electrodes next to each other; a first insulating layer provided on the main surface of the substrate and positioned on the first connecting electrode, second connecting electrodes provided on the first insulating layer and connecting the second detection electrodes next to each other; and a second insulating layer provided between the main surface of the substrate and at least one of the first detection electrodes, the second detection electrodes, and the first connecting electrodes, the second insulating layer separating the main surface of the substrate from the at least one of the first detection electrodes, the second detection electrodes, and the first connecting electrodes. 
     An embodiment of a display device according to the present invention includes the input device described above, a display panel arranged to face the input device, and a casing that houses the display panel. 
     An embodiment of an electronic apparatus according to the present invention includes the display device described above. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a plan view showing a schematic structure of an input device according to a first embodiment of the present invention. 
         FIG. 2  is a cross-sectional view taken along line I-I in  FIG. 1 . 
         FIG. 3  is a cross-sectional view taken along line II-II in  FIG. 1 . 
         FIG. 4( a )  is a diagram obtained by observation of a cross section of a glass substrate with a scanning electron microscope and 
         FIG. 4( b )  is a diagram showing a potassium ion concentration distribution observed by electron beam microanalysis on the cross section of the glass substrate. 
         FIG. 5( a )  is a diagram obtained by observation of a cross section of a glass substrate with a scanning electron microscope. In  FIG. 5( a ) , an electrode is disposed on a part of a main surface. 
         FIG. 5( b )  is a diagram showing a potassium ion concentration distribution observed by electron beam microanalysis on the cross section of the glass substrate. In  FIG. 5( b )  also, an electrode is formed on a part of the main surface. 
         FIG. 6  is a diagram showing a potassium ion concentration distribution observed by electron beam microanalysis on a cross section of a glass substrate. In  FIG. 6 , an insulating layer is disposed on a main surface of the glass substrate and an electrode is disposed on the insulating layer. 
         FIG. 7  is a cross-sectional view taken along line III-III in  FIG. 1 . 
         FIG. 8  is a cross-sectional view showing another example of the above-described input device and shows the same portion as in  FIG. 7 . 
         FIG. 9  is a cross-sectional view showing yet another example of the above-described input device and shows the same portion as in  FIG. 7 . 
         FIG. 10  is a cross-sectional view showing still another example of the above-described input device and shows the same portion as in  FIG. 7 . 
         FIG. 11  is a cross-sectional view showing a schematic structure of a display device according to the first embodiment of the present invention. 
         FIG. 12  is a perspective view showing a schematic structure of a portable terminal according to the first embodiment of the present invention. 
         FIG. 13  is a plan view showing a schematic structure of an input device according to a second embodiment of the present invention. 
         FIG. 14  is a cross-sectional view taken along line IV-IV in  FIG. 13 . 
         FIG. 15  is a cross-sectional view taken along line V-V in  FIG. 13 . 
         FIG. 16  is a plan view showing a schematic structure of an input device according to a third embodiment of the present invention. 
         FIG. 17  is a cross-sectional view taken along line VI-VI in  FIG. 16 . 
         FIG. 18  is a cross-sectional view taken along line VII-VII in  FIG. 16 . 
         FIG. 19  is a cross-sectional view showing another example of the above-described input device and shows the same portion as in  FIG. 17 . 
         FIG. 20  is a cross-sectional view showing yet another example of the above-described input device and shows the same portion as in  FIG. 18 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention will now be described with reference to drawings. 
     It should be noted that for the sake of convenience, the drawings referred to in the description below provide simplified representations of main components needed to explain the present invention among the structural components of an embodiment of the present invention. Accordingly, the input device, the display device, and the electronic apparatus according to the present invention may each include any structural component not shown in the drawings referred to in this specification. 
     First Embodiment 
     Referring to  FIG. 1 , an input device X 1  according to this embodiment is a capacitive touch panel. The input device X 1  has an input region E 1  and a non-input region E 2 . The input region E 1  allows a user to perform an input operation. The non-input region E 2  does not allow a user to perform an input operation. The non-input region E 2  according to this embodiment is located outside the input region E 1  so as to surround the input region E 1  but is not limited to this region. For example, the non-input region E 2  may be located within the input region E 1 . 
     As shown in  FIGS. 1 to 3 , the input device X 1  includes a substrate  2 . 
     The substrate  2  supports first detection electrodes  3   a , first connecting electrodes  3   b , second detection electrodes  4   a , and second connecting electrodes  4   b  in the input region E 1 . The substrate  2  supports detection wires  7  in the non-input region E 2 . The substrate  2  has a first main surface  2   a , a second main surface  2   b , and an end surface  2   c . The first main surface  2   a  is a surface on which an input operation is performed by a user through a protective sheet  11  described below. The second main surface  2   b  is a surface opposite of the first main surface  2   a . The end surface  2   c  is the surface adjacent to the first main surface  2   a  and the second main surface  2   b.    
     The substrate  2  has an insulating property. The substrate  2  has optical transparency to light incident in a direction intersecting the first main surface  2   a  and the second main surface  2   b . It should be noted that, in this specification, the “optical transparency” means transparency for visible light. Although the contour of the substrate  2  of this embodiment is substantially rectangular with rounded corners in a plan view, the contour is not limited to this. The corners need not be rounded and the contour of the substrate  2  may be circular or triangular, for example, in a plan view. 
     Examples of the material constituting the substrate  2  include those having optical transparency such as glass or plastic. Among these, glass is preferable from the viewpoint of visibility. Among various types of glasses, a strengthened glass is particularly preferable from the viewpoint of improving the strength of the substrate  2 . Thus, in this embodiment, a strengthened glass chemically strengthened by ion exchange is used as a material constituting the substrate  2 . In the case where the substrate  2  is formed of a strengthened glass, the substrate  2  is produced by the following method, for example. 
     That is, a glass is brought into contact with an aqueous solution containing potassium ions and heated to substitute sodium ions present in the surface layer of the glass by potassium ions. As the sodium ions present in the surface layer of the glass are substituted by potassium ions, a compression stress layer is formed on the surface layer of the glass. In other words, because potassium ions have a larger particle diameter than the sodium ions, potassium ions occupying holes formed by removal of the sodium ions help achieve higher compression stress on a molecular level. As a result, a chemically strengthened substrate  2  is obtained. 
     As shown in  FIGS. 1 to 3 , the first detection electrodes  3   a , the first connecting electrodes  3   b , the second detection electrodes  4   a , the second connecting electrodes  4   b , and first insulating layers  5  are formed on the second main surface  2   b  of the substrate  2  corresponding to the input region E 1 . 
     The first detection electrodes  3   a  each have a function of generating a capacitance between the electrode and a finger F 1 . The first detection electrode  3   a  detects a Y-direction position of the input made by the user&#39;s finger F 1  near the input region E 1 . The first detection electrodes  3   a  are disposed on the second main surface  2   b  of the substrate  2  and spaced from each other by particular gaps therebetween in an X direction (first direction). Although the shape of the first detection electrodes  3   a  in this embodiment is substantially rhombic in a plan view from the standpoint of improving detection sensitivity, the shape is not limited to this. 
     The first connecting electrodes  3   b  electrically connects adjacent first detection electrodes  3   a  to each other. The first connecting electrodes  3   b  are disposed on the second main surface  2   b  of the substrate  2 . 
     The second detection electrodes  4   a  each have a function of generating a capacitance between the electrode and the finger F 1 . The second detection electrodes  4   a  detect an X-direction position of the input made by the user&#39;s finger F 1  near the input region E 1 . The second detection electrodes  4   a  are disposed on the second main surface  2   b  of the substrate  2  and spaced from each other by particular gaps therebetween in a Y direction (second direction). Although the shape of the second detection electrodes  4   a  in this embodiment is substantially rhombic in a plan view from the standpoint of improving detection sensitivity, the shape is not limited to this. 
     The second connecting electrodes  4   b  electrically connect the second detection electrodes  4   a  adjacent to each other. Each second connecting electrode  4   b  is disposed on the first insulating layer  5  so as to cross the first insulating layer  5  and be electrically insulated from the first connecting electrode  3   b . The first insulating layer  5  is disposed on the second main surface  2   b  of the substrate  2  so as to cover the first connecting electrode  3   b . Examples of the material constituting the first insulating layer  5  include transparent resins such as acrylic resins, epoxy resins, silicone resins, and urethane resins. Examples of the method for forming the first insulating layer  5  include a transfer printing method, a spin coating method, and a slit coating method. 
     Examples of the material constituting the first detection electrodes  3   a , the first connecting electrodes  3   b , the second detection electrodes  4   a , and the second connecting electrodes  4   b  include electrically conductive materials having optical transparency. Examples of the electrically conductive materials having optical transparency include ITO (indium tin oxide), IZO (indium zinc oxide), ATO (antimony tin oxide), AZO (Al-doped zinc oxide), tin oxide, zinc oxide, and conductive polymers. 
     The first detection electrodes  3   a , the first connecting electrodes  3   b , the second detection electrodes  4   a , and the second connecting electrodes  4   b  are formed by, for example, forming films of the above-described materials on the second main surface  2   b  of the substrate  2  by a sputtering method, a vapor deposition method, or a CVD (chemical vapor deposition) method. A photosensitive resin is applied to a surface of the resulting film and the resulting film is patterned through exposure, development, and etching steps. As a result, the first detection electrodes  3   a , the first connecting electrodes  3   b , the second detection electrodes  4   a , and the second connecting electrodes  4   b  are formed. 
     Referring to  FIGS. 2 and 3 , a second insulating layer  6  is disposed between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  and between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 . The second insulating layer  6  is also disposed between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2 . In this embodiment, the second insulating layer  6  is disposed on the substantially entire second main surface  2   b  of the substrate  2  corresponding to the input region E 1 . In this specification, “substantially” is a concept that includes production errors and the like. 
     Since the second insulating layer  6  is formed between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  and between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 , the first detection electrodes  3   a  and the second detection electrodes  4   a  are separated from the second main surface  2   b  of the substrate  2 . Since the second insulating layer  6  is disposed between the second main surface  2   b  of the substrate  2  and the first connecting electrodes  3   b , the second main surface  2   b  of the substrate  2  becomes separated from the first connecting electrodes  3   b.    
     The second insulating layer  6  lowers the possibility of the decrease in strength of the substrate  2 . Examples of the material constituting the second insulating layer  6  are the same as those for the first insulating layers  5 . Examples of the method for forming the second insulating layer  6  are also the same as those for the first insulating layers  5 . 
     Consider a conventional input device in which first detection electrodes, second detection electrodes, and first connecting electrodes are directly formed on a second main surface of a substrate. Because the first detection electrodes, the second detection electrodes, and the first connecting electrodes are directly formed on the second main surface of the substrate in the conventional input device, there was a possibility that the strength of the substrate would be lowered. The reason for this is described below with reference to  FIGS. 4 and 5 . 
       FIG. 4( a )  is an image of a cross section of a glass substrate  50  observed with a scanning electron microscope.  FIG. 4( b )  shows the potassium ion concentration distribution found by electron beam microanalysis on the cross section of the glass substrate  50 .  FIG. 4( b )  and  FIG. 4( b )  show the same section. Here, as with the substrate  2  of the present embodiment, a strengthened glass chemically strengthened by ion exchange is used as the glass substrate  50 . In both  FIGS. 4( a ) and ( b ) , no electrodes are formed on a main surface  50   a  of the glass substrate  50 . The glass substrate  50  is a glass substrate in an original state. 
     As shown in  FIGS. 4( a ) and 4( b ) , a compression stress layer  51  is formed in the glass substrate  50  from the main surface  50   a  down to a certain depth. In this embodiment, this certain depth is 17 μm. As shown in  FIG. 4( b ) , no electrodes are formed on the main surface  50   a  of the glass substrate  50 . It can be understood that potassium ions are evenly distributed in the compression stress layer  51  if the glass substrate  50  is a glass substrate in an original state. 
       FIG. 5( a )  is an image of a cross section of the glass substrate  50  observed with a scanning electron microscope. In  FIG. 5( a ) , an electrode  60  is formed on a part of the main surface  50   a .  FIG. 5( b )  shows the potassium ion concentration distribution found by electron beam microanalysis on the cross section of the glass substrate  50 . In  FIG. 5( b )  also, an electrode  60  is formed on a part of the main surface  50   a .  FIGS. 5( a ) and 5( b )  show the same section. The material constituting the electrode  60  is the same as those for the first detection electrodes  3   a  and the second detection electrodes  3   b . The electrode  60  is formed on the main surface  50   a  of the glass substrate  50  by sputtering. 
       FIG. 5( b )  shows that potassium ions are concentrated in a portion C 1  in the compression stress layer  51  located directly bellow the electrode  60 . In this embodiment, it was found that extensive concentration of potassium ions was observed in a region of the compression stress layer  51  from the main surface  50   a  down to a depth of 3 μm. In other words, because potassium ions are highly concentrated in the portion C 1 , cracks may readily occur in the glass substrate  50 , starting from the boundary between the portion C 1  and a portion C 2  in the compression stress layer  51  where the electrode  60  is absent. As a result, the strength of the glass substrate  50  is decreased. 
     What causes potassium ions to concentrate in the portion C 1  in the compression stress layer  51  located directly below the electrode  60 , leading to a difference in potassium ion concentration distribution between the portion C 1  and the portion C 2 , is not known in details but may be explained as follows. That is, in forming the electrode  60  by sputtering on the main surface  50   a  of the glass substrate  50 , thermal energy generated by sputtering causes the electrode  60  to react with potassium ions and the potassium ions to migrate toward the electrode  60 . In the portion C 2  where the electrode  60  is absent, potassium ions in the compression stress layer  51  do not react with the electrode  60 . However, in the portion C 2 , the potassium ions migrate toward the interior of the more stable glass substrate  50  by the thermal energy caused by sputtering. As a result, potassium ions are concentrated in the portion C 1  and a difference in potassium ion concentration distribution is generated between the portion C 1  and the portion C 2 . The same applies when the electrode  60  is formed on the main surface  50   a  of the glass substrate  50  by a vapor deposition method or a CVD method. 
       FIG. 6  shows the potassium ion concentration distribution found by electron beam microanalysis of a cross section of the glass substrate  50 . In  FIG. 6 , an insulating layer  70  is disposed on the main surface  50   a  of the glass substrate  50  and the electrode  60  is disposed on the insulating layer  70 . The material constituting the insulating layer  70  is the same as that of the second insulating layer  6 . The insulating layer  70  is formed on the main surface  50   a  of the glass substrate  50  by a spin coating method. As shown in  FIG. 6 , potassium ions are evenly distributed in the compression stress layer  51 . 
     In other words, the insulating layer  70  is temporarily formed on the main surface  50   a  of the glass substrate  50  so that the thermal energy generated by sputtering in forming the electrode  60  on the insulating layer  70  by sputtering is blocked by the insulating layer  70 . As a result, the possibility that the potassium ions in the portion C 1  would react with the electrode  60  and migrate toward the electrode  60  can be lowered. Moreover, the possibility that the potassium ions in the portion C 2  would migrate toward the interior of the glass substrate  50  can be lowered. As such, if the insulating layer  70  is temporarily formed on the main surface  50   a  of the glass substrate  50  and then the electrode  60  is formed on the insulating layer  70 , the possibility that the potassium ions would become concentrated in the portion C 1 , thereby creating a difference in potassium ion concentration distribution between the portion C 1  and the portion C 2 , can be lowered. Thus, according to the structure shown in  FIG. 6 , the possibility of the decrease in strength of the glass substrate  50  can be lowered. 
     As described above, in this embodiment, the second insulating layer  6  is disposed between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  and between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 . Accordingly, the first detection electrodes  3   a  and the second detection electrodes  4   a  are separated from the second main surface  2   b  of the substrate  2 . Moreover, since the second insulating layer  6  is disposed between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2 , the first connecting electrodes  3   b  are separated from the second main surface  2   b  of the substrate  2 . Thus, in the input device X 1 , the possibility of the decrease in strength of the substrate  2  can be lowered. 
     As shown in  FIG. 7 , the detection wires  7 , a third insulating layer  8 , and a protective layer  9  are disposed on the second main surface  2   b  of the substrate  2  corresponding to the non-input region E 2 . 
     The detection wires  7  detect changes in capacitance generated between the first detection electrodes  3   a  and the finger F 1  and between the second detection electrodes  4   a  and the finger F 1 . In this embodiment, as shown in  FIG. 1 , plural detection wires  7  are disposed in the non-input region E 2  located along one of the long sides of the substrate  2  as well as in the non-input region E 2  located at one of the short sides of the substrate  2 . The detection wires  7  have one ends electrically connected to the first detection electrodes  3   a  and the second detection electrodes  4   a  and the other ends located in an outer conduction region G 1 . A flexible substrate not shown in the drawing is connected to the outer conduction region G 1 . The flexible substrate is, for example, equipped with a position detection driver not shown in the drawing. 
     The detection wires  7  are formed of metal thin films, for example. When the detection wires  7  are formed of metal thin films, high hardness and high shape stability are achieved, which is preferable. Examples of the metal thin films include aluminum films, aluminum alloy films, laminate films of chromium films and aluminum films, laminate films of chromium films and aluminum alloy films, silver films, silver alloy films, and gold alloy films. Examples of the method for forming the metal thin films include a sputtering method, a vapor deposition method, and a CVD method. 
     The third insulating layer  8  is disposed between the detection wires  7  and the second main surface  2   b  of the substrate  2 . As a result, the detection wires  7  are separated from the second main surface  2   b  of the substrate  2 . In this embodiment, the third insulating layer  8  is provided substantially over the entire second main surface  2   b  of the substrate  2  corresponding to the non-input region E 2 . Since the third insulating layer  8  is disposed between the detection wires  7  and the second main surface  2   b  of the substrate  2 , the possibility of the decrease in strength of the substrate  2  can be lowered as with the case in which the second insulating layer  6  is disposed between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  and between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2  and the case in which the second insulating layer  6  is disposed between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2 . 
     Examples of the material constituting the third insulating layer  8  are the same as those of the first insulating layers  5  and the second insulating layer  6 . Examples of the method for forming the third insulating layer  8  are the same as those of the first insulating layers  5  and the second insulating layer  6 . 
     The second insulating layer  6  and the third insulating layer  8  may be formed simultaneously on the second main surface  2   b  of the substrate  2  in the same step. In such a case, although the second insulating layer  6  is distinguished from the third insulating layer  8  in this embodiment, one insulating layer is actually formed on the second main surface  2   b  of the substrate  2  corresponding to the input region E 1  and the non-input region E 2 . In such a case, the insulating layer located between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2 , between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 , and between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2  is the second insulating layer  6 , and the insulating layer located between the detection wires  7  and the second main surface  2   b  of the substrate  2  is the third insulating layer  8 . Alternatively, the second insulating layer  6  and the third insulating layer  8  may be separately formed by separate steps on the second main surface  2   b  of the substrate  2 . 
     As shown in  FIG. 8 , the third insulating layer  8  is preferably separated from an edge  21  at the end surface  2   c  of the substrate  2  and on the second main surface  2   b  side. In the example shown in  FIG. 8 , the third insulating layer  8  is distant from the edge  21  at the end surface  2   c  of the substrate  2  by a particular distance L1. In this embodiment, L1 is in the range of 0.85 to 1.15 mm. When the third insulating layer  8  is separated from the edge  21  at the end surface  2   c  of the substrate  2 , the possibility of detachment of the third insulating layer  8  from the second main surface  2   b  of the substrate  2  can be lowered. 
     As shown in  FIG. 7 , in the case where the third insulating layer  8  is provided up to the edge  21  at the end surface  2   c  of the substrate  2 , there is a possibility that the third insulating layer  8  would detach from the second main surface  2   b  of the substrate  2  starting from the third insulating layer  8  at the edge  21 . To be more specific, if the substrate  2  is repeatedly pressed by a user, stress acts on the third insulating layer  8  at the edge  21  of the end surface  2   c  of the substrate  2 , and the third insulating layer  8  at the edge  21  of the end surface  2   c  of the substrate  2  possibly becomes the starting point from which the third insulating layer  8  detaches from the second main surface  2   b  of the substrate  2 . Moreover, in the process of producing the input device X 1 , for example, when the end surface  2   c  of the substrate  2  is physically or chemically polished, there is a possibility that the third insulating layer  8  would detach from the second main surface  2   b  of the substrate  2  by polishing. 
     In contrast, according to an example shown in  FIG. 8  in which the third insulating layer  8  is separated from the edge  21  at the end surface  2   c  of the substrate  2 , the possibility of occurrence of the aforementioned problem can be lowered. Accordingly, compared to the example shown in  FIG. 7 , the example shown in  FIG. 8  can lower the possibility of detachment of the third insulating layer  8  from the second main surface  2   b  of the substrate  2 . 
     The protective layer  9  protects the detection wires  7 . An example of protection provided to the detection wires  7  is protection of the detection wires  7  from the corrosion caused by absorption of moisture. The protective layer  9  covers the detection wires  7 . Examples of the material constituting the protective layer  9  include transparent resins such as acrylic resins, epoxy resins, silicone resins, and urethane resins. Examples of the method for forming the protective layer  9  include a transfer printing method, a spin coating method, and a slit coating method. 
     A third connecting electrode  7   a  electrically connects the first detection electrode  3   a  and the second detection electrode  4   a  to the detection wires  7 . The third connecting electrode  7   a  has one end electrically connected to the first detection electrode  3   a  and the second detection electrode  4   a  and the other end electrically connected to the detection wire  7  through a through hole  9   a  formed in the protective layer  9  and extending from the upper surface of the protective layer  9 . Examples of the material constituting the third connecting electrode  7   a  are the same as those of the first connecting electrodes  3   b  and the second connecting electrodes  4   b . Examples of the method for forming the third connecting electrode  7   a  are the same as those for the first connecting electrodes  3   b  and the second connecting electrodes  4   b.    
     As shown in  FIG. 7 , the protective layer  9  preferably has a curved inner edge  91  on the input region E 1  side. When the inner edge  91  is curved, the possibility of detachment of the third connecting electrode  7   a  located on the inner edge  91  can be lowered. Moreover, when the inner edge  91  is curved, the stress acting on the protective layer  9  upon user&#39;s input operation can be relaxed at the inner edge  91 . 
     As shown in  FIGS. 2, 3, and 7 , the protective sheet  11  is disposed on the first main surface  2   a  of the substrate  2  corresponding to the input region E 1  and the non-input region E 2  with an adhesive layer  10  therebetween. 
     The protective sheet  11  protects the first main surface  2   a  of the substrate  2  from being scratched by the user&#39;s finger F 1 . The protective sheet  11  is formed on the entire first main surface  2   a  of the substrate  2  with the adhesive layer  10  therebetween. The protective sheet  11  may be formed only on the first main surface  2   a  of the substrate  2  corresponding to the input region E 1 . Examples of the material constituting the protective sheet  11  include glass, plastic, and polyethylene terephthalate films. Examples of the material constituting the adhesive layer  10  include acrylic resins, urethane resins, epoxy resins, silicone resins, phenolic resins, and polyamide resins. 
     A color layer may be provided in the protective sheet  11  corresponding to the non-input region E 2 . According to this structure, the non-input region E 2  of the input device X 1  can be decorated. 
     If there is no need to prevent scratching of the first main surface  2   a  of the substrate  2  by the user&#39;s finger F 1 , the protective sheet  11  does not have to be provided on the first main surface  2   a  of the substrate  2 . 
     As shown in  FIGS. 2, 3, and 7 , a protective member  12  is provided on the second main surface  2   b  of the substrate  2  corresponding to the input region E 1  and the non-input region E 2 . 
     The protective member  12  protects the first detection electrodes  3   a , the first connecting electrodes  3   b , the second detection electrodes  4   a , the second connecting electrodes  4   b , and the third connecting electrode  7   a . Examples of the protection provided to the first detection electrodes  3   a , the first connecting electrodes  3   b , the second detection electrodes  4   a , the second connecting electrodes  4   b , and the third connecting electrode  7   a  include protection from the corrosion caused by absorption of moisture and a role of lowering the possibility of malfunction of the input device X 1  by entrance of static electricity. Examples of the material constituting the protective member  12  include silicon dioxide and silicon nitride. Examples of the method for forming the protective member  12  include a sputtering method, an ion plating method, a screen printing method, and an ink jet printing method. 
     Next, the principle of detection in the input device X 1  is described. 
     A position detection driver is electrically connected to the detection wires  7  located in the outer conduction region G 1 . The position detection driver includes a power supply unit. The power supply unit of the position detection driver provides a voltage to the first detection electrodes  3   a  and the second detection electrodes  4   a . When the finger F 1 , which is a conductor, approaches the first main surface  2   a  of the substrate  2  corresponding to the input region E 1  with the protective sheet  11  therebetween, a capacitance is generated between the finger F 1  and the first detection electrode  3   a  and between the finger F 1  and the second detection electrode  4   a . The position detection driver constantly detects the capacitance generated at the first detection electrodes  3   a  and the second detection electrodes  4   a . The position detection driver detects the input position where the user performed the input operation on the basis of the combination of the first detection electrode  3   a  and the second detection electrode  4   a  at which a capacitance of a particular value or higher is detected. As such, the input device X 1  can detect the input position. 
     As described above, the input device X 1  can lower the possibility of the decrease in strength of the substrate  2 . 
     As shown in  FIG. 9 , a light-shielding layer  13  may be provided between the third insulating layer  8  and the second main surface  2   b  of the substrate  2 . In particular, the light-shielding layer  13  is disposed on the second main surface  2   b  of the substrate  2  and the third insulating layer  8  is disposed on the second main surface  2   b  of the substrate  2  and covers the light-shielding layer  13 . In this embodiment, the light-shielding layer  13  has a frame shape surrounding the input region E 1  and is disposed on the second main surface  2   b  of the substrate  2  corresponding to the non-input region E 2 . 
     The light-shielding layer  13  has a light-shielding property. In this specification, the “light-shielding property” is a property to shield some or all components of visible light by reflection or absorption. Examples of the material constituting the light-shielding layer  13  are resin materials containing coloring materials. Examples of the resin material include transparent resins such as acrylic resins, epoxy resins, silicone resins, and urethane resins. Examples of the coloring material include carbon, titanium, and chromium. The color of the light-shielding layer  13  is not limited to black and may be any other color. Examples of the method for forming the light-shielding layer  13  include a screen printing method, a sputtering method, a CVD method, and a vapor deposition method. 
     The detection wires  7  are formed on the light-shielding layer  13  with the third insulating layer  8  therebetween. Since the detection wires  7  are formed on the light-shielding layer  13  with the third insulating layer  8  therebetween, the possibility that the detection wire  7  would become recognizable by the user can be lowered. 
     In order to decrease the possibility that the detection wires  7  would become recognizable by the user, preferably all of the detection wires  7  are disposed on the light-shielding layer  13  with the third insulating layer  8  therebetween. However, it is not necessary that all detection wires  7  be disposed on the light-shielding layer  13  with the third insulating layer  8  therebetween. In other words, it would suffice if at least some of the detection wires  7  are disposed on the light-shielding layer  13  with the third insulating layer  8  therebetween. 
     Alternatively, as shown in  FIG. 10 , the light-shielding layer  13  may be disposed on the third insulating layer  8 . In this case, the detection wires  7  are disposed on the light-shielding layer  13 . Since the detection wires  7  are disposed on the light-shielding layer  13 , the possibility that the detection wires  7  would become recognizable by the user can be lowered. 
     Next, a display device Y 1  that includes the input device X 1  is described with reference to  FIG. 11 . 
     As shown in  FIG. 11 , the display device Y 1  according to this embodiment includes the input device X 1 , a liquid crystal panel  101 , a backlight  102 , a circuit board  103 , and a first casing  104 . 
     The liquid crystal panel  101  is a display panel that uses a liquid crystal composition for display. The liquid crystal panel  101  is arranged to oppose the input device X 1  with a space S 1  therebetween. A display panel such as a plasma panel, an organic EL panel, or an electronic paper may be used instead of the liquid crystal panel  101 . The organic EL panel is a display panel that uses a substance that emits light upon application of voltage. In particular, in an organic EL panel, an illuminant that contains an organic substance such as a diamine is vapor-deposited on a substrate and display is performed by applying a direct voltage of 5 to 10 V. If an organic EL panel is used instead of the liquid crystal panel  101 , the backlight  102  is no longer necessary. 
     The backlight  102  includes a light source  102   a  and a light guiding panel  102   b . The light source  102   a  emits light toward the light guiding panel  102   b . The backlight  102  is constituted by, for example, LEDs (light-emitting diodes). A cold cathode fluorescent lamp, a halogen lamp, a xenon lamp, or EL (electro-luminescence) may be used instead of LEDs. The light guiding panel  102   b  substantially evenly guides light from the light source  102   a  over the entire lower surface of the liquid crystal panel  101 . 
     The circuit board  103  is a plate-shape or a film-shape board in which parts such as ICs (integrated circuits), resistors, and capacitors are mounted on a surface and connected to one another with wires so as to constitute an electronic circuit. The circuit board  103  is disposed on the rear side of the backlight  102 . The circuit board  103  includes a connector. A flexible substrate connected to the outer conduction region G 1  is inserted into the connector. 
     The first casing  104  houses the liquid crystal panel  101 , the backlight  102 , and the circuit board  103 . Examples of the material constituting the first casing  104  include resins such as polycarbonate or metals such as stainless steel and aluminum. 
     The first casing  104  includes a supporting member  104   a . The supporting member  104   a  supports the input device X 1 . In particular, the supporting member  104   a  supports the non-input region E 2  by surrounding the input region E 1 . The input device X 1  is bonded to the supporting member  104   a  with an adhesive member such as a double-sided adhesive tape or the like. 
     As such, various types of data can be input to the input device X 1  by performing input operation in the input region E 1  while watching the liquid crystal panel  101 . Note that the input device X 1  may be provided with a function of causing various sensations, such as pressing sensations, tracing sensations, and feel sensations, to the user inputting the data in inputting various types of data. In such a case, the substrate  2  of the input device X 1  includes one or more piezoelectric elements so that when a particular input operation or a particular pressing load is detected, the piezoelectric elements can be vibrated at a particular frequency. 
     Since the display device Y 1  includes the input device X 1 , the possibility of the decrease in strength of the substrate  2  can be lowered. 
     Although the example described above is an example in which the input device X 1  opposes the liquid crystal panel  101  with the space S 1  therebetween, the example is not limiting. The input device X 1  may be arranged to oppose the liquid crystal panel  101  without the space S 1  therebetween. In other words, the input device X 1  may be arranged to oppose and make contact with the liquid crystal panel  101 . 
     Next, a portable terminal P 1  including the display device Y 1  is described with reference to  FIG. 12 . 
     As shown in  FIG. 12 , the portable terminal P 1  of this embodiment is an electronic apparatus such as a cellular phone, a smart phone, a PDA (personal digital assistant), or the like. The portable terminal P 1  includes the display device Y 1 , a sound input unit  201 , a sound output unit  202 , a key input unit  203 , and a second casing  204 . 
     The sound input unit  201  is constituted by a microphone, for example, and voice or the like of the user is input to the sound input unit  201 . The sound output unit  202  is constituted by a speaker or the like and voice or the like from person at the other end is output from the sound output unit  202 . The key input unit  203  is constituted by, for example, mechanical keys. The key input unit  203  may be operation keys displayed in the display screen. The second casing  204  houses the display device Y 1 , the sound input unit  201 , the sound output unit  202 , and the key input unit  203 . 
     The portable terminal P 1  may additionally include a digital camera unit, a one-segment broadcasting tuner, a near field communication unit such as an infrared transmission functional unit, and various types of interfaces depending on the required functions. However, detail illustrations and descriptions of these units are omitted. 
     Since the portable terminal P 1  includes the display device Y 1 , the possibility of the decrease in strength of the substrate  2  can be lowered. 
     Note that although an example of the portable terminal P 1  that includes the sound input unit  201  is described above, this example is not limiting. That is, the portable terminal P 1  need not include the sound input unit  201 . 
     Moreover, although an example of the portable terminal P 1  that includes the second casing  204  housing the display device Y 1 , the sound input unit  201 , the sound output unit  202 , and the key input unit  203  is described above, this example is not limiting. The second casing  204  need not be separately provided and the first casing  104  of the display device Y 1  may serve as the casing of the portable terminal P 1 . 
     The display device Y 1  may be installed in various types of electronic appliances such as an industrial programmable display device, a vehicle-mounted display device, an electronic organizer, a personal computer, a copy machine, a terminal machine for gaming, a television, and a digital camera, instead of the portable terminal P 1 . 
     Second Embodiment 
       FIG. 13  is a plan view showing a schematic structure of an input device X 2  according to this embodiment.  FIG. 14  is a cross-sectional view taken along line IV-IV in  FIG. 13 .  FIG. 15  is a cross-sectional view taken along line V-V in  FIG. 13 . In  FIGS. 13 to 15 , the structures having the same functions as those in  FIGS. 1 to 3  are represented by the same reference signs and the detail descriptions thereof are omitted. 
     As shown in  FIGS. 14 and 15 , the input device X 2  includes a second insulating layer  61  instead of the second insulating layer  6  in the first embodiment. 
     The second insulating layer  61  is formed between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  and between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 . As a result, the first detection electrodes  3   a  and the second detection electrodes  4   a  become separated from the second main surface  2   b  of the substrate  2 . In this embodiment, the second insulating layer  61  is not disposed between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2 . In other words, the first connecting electrodes  3   b  are disposed on the second main surface  2   b  of the substrate  2  without the second insulating layer  61  therebetween. 
     In this input device X 2 , the second insulating layer  61  is disposed between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  and between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2  but not between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2 . Thus, although the input device X 2  can lower the possibility of the decrease in strength of the substrate  2  compared to conventional input devices, there is still a possibility of the decrease in strength of the substrate  2  at the portion corresponding to the first connecting electrodes  3   b  compared to the input device X 1 . 
     However, in the input device X 2 , the second insulating layer  61  is disposed between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  and between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 , but not between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2 . Accordingly, the height position of the first detection electrodes  3   a  and the second detection electrodes  4   a  with respect to the second main surface  2   b  of the substrate  2  approaches the height position of the second connecting electrodes  4   b  with respect to the second main surface  2   b  of the substrate  2 . Thus, the possibility that the transmittance and reflectance for visible light differ between the portion where the first detection electrodes  3   a  and the second detection electrodes  4   a  are formed and the portion where the second connecting electrodes  4   b  are formed can be lowered. Accordingly, when the input device X 2  is installed in a display device, the display quality of the display device is improved. 
     The height position of the first detection electrodes  3   a  and the second detection electrodes  4   a  with respect to the second main surface  2   b  of the substrate  2  and the height position of the second connecting electrodes  4   b  with respect to the second main surface  2   b  of the substrate  2  are preferably substantially the same. In other words, in this embodiment, since the second main surface  2   b  of the substrate  2  is substantially flat, the height H1 of the first detection electrodes  3   a  and the second detection electrodes  4   a  with respect to the second main surface  2   b  of the substrate  2  is substantially the same as the height H2 of the second connecting electrodes  4   b  with respect to the second main surface  2   b  of the substrate  2 . According to this structure, the visible-light transmittance and reflectance of the portion where the first detection electrodes  3   a  and the second detection electrodes  4   a  are formed becomes substantially the same as those of the portion where the second connecting electrodes  4   b  are formed. As a result, when the input device X 2  is installed in the display device, the display quality of the display device is further improved. 
     As discussed above, compared to typical input devices, the input device X 2  can decrease the possibility of the decrease in strength of the substrate  2 . Moreover, when the input device X 2  is installed in a display device, the display quality of the display device is improved. 
     Third Embodiment 
       FIG. 16  is a plan view showing a schematic structure of an input device X 3  according to this embodiment.  FIG. 17  is a cross-sectional view taken along line VI-VI in  FIG. 16 .  FIG. 18  is a cross-sectional view taken along line VII-VII in  FIG. 16 . In  FIGS. 16 to 18 , the structures having the same functions as those in  FIGS. 1 to 3  are represented by the same reference signs and the detail descriptions thereof are omitted. 
     As shown in  FIGS. 17 and 18 , the input device X 3  includes a second insulating layer  62  instead of the second insulating layer  6  in the first embodiment. 
     The second insulating layer  62  is disposed between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2 . As a result, the first connecting electrode  3   b  is separated from the second main surface  2   b  of the substrate  2 . In this embodiment, the second insulating layer  62  is not disposed between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  and between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 . In other words, the first detection electrodes  3   a  and the second detection electrodes  4   a  are disposed on the second main surface  2   b  of the substrate  2  without the second insulating layer  62  therebetween. 
     As described above, in the input device X 3 , the second insulating layer  62  is disposed between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2  but not between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  or between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 . Accordingly, compared to typical input devices, the input device X 3  can lower the possibility of the decrease in strength of the substrate  2 ; however, compared to the input device X 1 , there is a possibility of the decrease in strength of the substrate  2  in the portion corresponding to the first detection electrodes  3   a  and the second detection electrodes  4   a.    
     However, in the input device X 3 , the second insulating layer  62  is not disposed between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  or between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 . Accordingly, when the input device X 3  is installed in a display device, the display quality of the display device is improved. 
     In other words, the second insulating layer  62  is yellowish in color depending on the constitutional material. Thus, forming the second insulating layer  62  between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  and between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2  decreases the visibility of the input device X 3  although the possibility of the decrease in strength of the substrate  2  can be lowered. In other words, since the area of the first detection electrodes  3   a  and the second detection electrodes  4   a  in a plan view is significantly larger than the area of the first connecting electrodes  3   b  in a plan view, the transmittance of the input device X 3  is decreased by forming the second insulating layer  62  between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  and between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 . 
     Thus, in the input device X 3 , the second insulating layer  62  is disposed between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2  but not between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  or between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 . Accordingly, when the input device X 3  is installed in the display device Y 1 , the display quality of the display device Y 1  is improved. 
     As described above, compared to typical input devices, the input device X 3  can lower the possibility of the decrease in strength of the substrate  2 . Moreover, when the input device X 3  is installed in a display device, the display quality of the display device is improved. 
     In the input device X 3 , the second insulating layer  62  is disposed between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2  but not between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  or between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 . Accordingly, in the input device X 3 , the difference between the height position of the first detection electrodes  3   a  and the second detection electrodes  4   a  with respect to the second main surface  2   b  of the substrate  2  and the height position of the second connecting electrodes  4   b  with respect to the second main surface  2   b  of the substrate  2  is greater compared to that in the input device X 1 . In other words, the height position of the second connecting electrodes  4   b  with respect to the second main surface  2   b  of the substrate  2  is larger in the input device X 3  than in the input device X 1  and thus the intersections between the first connecting electrodes  3   b  and the second connecting electrodes  4   b  may become identifiable as dots by the user. 
     Accordingly, as shown in  FIGS. 19 and 20 , the input device X 3  preferably includes a light-scattering member  14  in the second insulating layer  62 . The light-scattering member  14  scatters light. Examples of the material constituting the light-scattering member  14  include silicon dioxide, aluminum oxide, titanium oxide, yttrium oxide, zirconium dioxide, and hollow silicon dioxide. 
     The light-scattering member  14  contained in the second insulating layer  62  scatters outside light entering from the outer side of the substrate  2  and inside light entering from the backlight  102 . Accordingly, the possibility that the intersections between the first connecting electrodes  3   b  and the second connecting electrodes  4   b  would be identified as dots by the user can be lowered. 
     The light-scattering member  14  may be contained in the first insulating layer  5  instead of the second insulating layer  62 . The light-scattering member  14  may be contained in the first insulating layer  5  and the second insulating layer  62 . 
     In the first embodiment, an example in which the second insulating layer  6  is disposed between the second main surface  2   b  of the substrate  2  and the first detection electrodes  3   a , between the second main surface  2   b  of the substrate  2  and the second detection electrodes  4   a , and between the second main surface  2   b  of the substrate  2  and the first connecting electrodes  3   b  is described. In the second embodiment, an example in which the second insulating layer  61  is disposed between the second main surface  2   b  of the substrate  2  and the first detection electrodes  3   a  and between the second main surface  2   b  of the substrate  2  and the second detection electrodes  4   a  is described. In the third embodiment, an example in which the second insulating layer  62  is disposed between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2  is described. However, the present invention is not limited to such embodiments. 
     For example, a second insulating layer may be disposed between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  but not between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2  or between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2 . Alternatively, for example, a second insulating layer may be disposed between the first detection electrodes  3   a  and the second main surface  2   b  of the substrate  2  and between the first connecting electrodes  3   b  and the second main surface  2   b  of the substrate  2  but not between the second detection electrodes  4   a  and the second main surface  2   b  of the substrate  2 . In other words, it is sufficient if a second insulating layer is disposed between the second main surface  2   b  of the substrate  2  and at least one of the first detection electrodes  3   a , the second detection electrodes  4   a , and the first connecting electrodes  3   b.    
     In the first to third embodiments, examples of the input devices X 1  to X 3  with which input operation is performed through the protective sheet  11  on the first main surface  2   a  of the substrate  2  are described. However, these examples are not limiting. That is, the input operation may be performed on the second main surface  2   b  of the substrate  2  through the protective member  12 . In this case, the protective sheet  11  need not be formed on the first main surface  2   a  of the substrate  2 . A protective sheet may be formed on the protective member  12 . If the input device is an input device with which input operation is performed on the second main surface  2   b  of the substrate  2  through the protective member  12 , a constitutional member of the display panel may be formed on the first main surface  2   a  of the substrate  2 . In the case where the display panel is a liquid crystal panel  2 , the constitutional member of the display panel may be, for example a color filter, a black matrix, or a common electrode. In other words, the input device may be of an on-cell type. 
     Although examples of the display device Y 1  that includes the input device X 1  are described above, the input device X 2  or the input device X 3  may be employed instead of the input device X 1 . A portable terminal that includes a display device that includes the input device X 2  or the input device X 3  may also be employed. 
     REFERENCE SIGNS LIST 
     
         
         
           
             X 1  to X 3  input device 
             Y 1  display device 
             P 1  portable terminal (electronic apparatus) 
               2  substrate 
               3   a  first detection electrode 
               3   b  first connecting electrode 
               4   a  second detection electrode 
               4   b  second connecting electrode 
               5  first insulating layer 
               6 ,  61 ,  62  second insulating layer 
               7  detection wire 
               8  third insulating layer 
               13  light-shielding layer 
               14  light-scattering member 
               101  liquid crystal panel (display panel) 
               104  first casing (casing)