Abstract:
A method for fabricating a capacitive curved touch panel is provided for solving the problems of the conventional methods, i.e., unsuitableness of the methods for mass production and fabricating large touch panels and touch panels of complicated curved surface shapes. The method includes the steps of (a) preparing a patterned plate  13  by forming an electrode layer having a plurality of electrode regions  15  on a thermoplastic resin plate  11  with an electrically-conductive ink comprised of an electrically-conductive substance and a binder, (b) preparing a soft curved product  21  by heating to soften the patterned plate  13  and shaping the softened patterned plate on a die  22 , and (c) cooling or allowing to cool the soft curved product to make the touch panel.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a capacitive touch panel having a curved touch surface, more specifically, a touch panel having a unique electrode composition. 
         [0002]    Further the present invention relates to a method for fabricating the touch panel and a display system to which the touch panel is built in. 
       BACKGROUND ART 
       [0003]    In the conventional technology, capacitive touch panels having a curved touch surface and a light scattering layer on their rear side have already been proposed (for example, those disclosed in Patent literature 1). Such conventional touch panels have electrodes for sensing a touch which consist of a transparent conductive membrane formed of specific metal oxides such as ITO (indium tin oxide), IZO (indium zinc oxide) and SnO 2  (tin oxide). The conductive membrane is formed in vacuum plating, such as sputtering. 
         [0004]    Touch panels usually function to determine the location of a touch, and for this purpose a plurality of electrodes are required to be precisely formed on a touch surface. 
         [0005]    Curved touch panels fabricated by forming a layer of a specific metal oxide on a curved substrate require pneumatic plating in their fabrication process, and materials employable for the curved substrate are restricted within those durable against pneumatic plating, such as soda glass, borosilicate glass and heat-resistant glasses. 
         [0006]    The pneumatic plating included in the methods for fabricating the conventional curved touch panels makes the methods unsuitable for mass production or causes difficulty in producing large touch panels. In addition, it is difficult in the conventional fabrication methods to precisely form a plurality of electrodes on a curved touch panel of a complicated curved surface shape. 
         [0007]    Further, a display system having a curved touch panel has limited application because of the material of the touch panel being restricted within glasses which are not resistant to an accidental shock. In addition, such system has several disadvantages including high production cost, unsuitableness for large size and impossibility for employing a display unit of a complicated curved surface shape. 
       CITATION LIST 
     Patent Literature 
       [0008]    PTL 1; Japanese patent publication laid open 2007-279819 
       SUMMARY OF INVENTION 
     Technical Problem  
       [0009]    The problem to be solved by the present invention relating to a curved touch panel is the narrow scope of materials selectable for fabricating a curved touch panel. Further the problems to be solved by the present invention relating to a method for fabricating a curved touch panel are the unsuitableness of the conventional methods for mass production, large touch panels and touch panels of complicated curved surface shapes. Further the problem to be solved by the present invention relating to a display system in which a touch panel is built in is the limited application of a display system with a touch panel because of the susceptibleness of a touch panel to an accidental shock. 
         [0010]    Other problems to be solved by the present invention will become apparent from the detailed description to follow. 
       Solution to Problem 
       [0011]    The means for solving the problems are explained in the following description. 
         [0012]    A touch panel according to one embodiment of the present invention is a capacitive touch panel having a curved touch surface that is fabricated; forming an electrode layer having a plurality of electrode regions on a thermoplastic resin plate with an electrically-conductive ink comprised of an electrically-conductive substance and a binder to prepare a patterned plate, said patterned plate is heated and softened to be shaped into a soft curved product; and said curved product is cooled or allowed to cool to be made into said touch panel. 
         [0013]    The touch panel of the present invention can be practiced according to the following preferable embodiments. 
         [0014]    (1) The thermoplastic resin plate is a light-scattering resin plate. 
         [0015]    (2) Said electrically-conductive substance in said electrically-conductive ink comprised of said electrically-conductive substance and said binder, is carbon nanotube. 
         [0016]    (3) Said electrode layer comprises a first electrode layer and a second electrode layer being superposed over said first electrode layer without direct contact, each of said first electrode layer and second electrode layer has a plurality of electrode regions, and one electrode region contained in said first electrode layer overlaps with at least two electrode regions contained in said second electrode layer. 
         [0017]    (4) Said plurality of the electrode regions contained in the electrode layers are formed by dividing an area coated with the electrically-conductive ink, which covers the whole area of the plurality of the electrode regions, by means of photolithography. 
         [0018]    The method for fabricating the touch panel according to another embodiment of the present invention is a method for fabricating a capacitive touch panel having a curved touch surface and includes the following steps of:
       (a) preparing a patterned plate by forming an electrode layer having a plurality of electrode regions on a thermoplastic resin plate with an electrically-conductive ink comprised of an electrically-conductive substance and a binder;   (b) heating and softening said patterned plate, and shaping said patterned plate into a soft curved product; and   (c) cooling or allowing to cool said soft curved product to make said touch panel.       
 
         [0022]    The display system having a touch panel according to yet another embodiment of the present invention comprises an image projection unit, a light-path-reflecting mirror, a touch panel of the present invention, a touch panel controller, a computer and an image memory unit. Said computer transmits an image data stored in said image memory unit to said image projection unit, said image projection unit produces and projects the image onto the light-path-reflecting mirror, said light-path-reflecting mirror reflects the incoming image and projects it onto said touch panel, and said touch panel displays the projected image. The electrode regions of said touch panel are electrically connected to said touch panel controller, said touch panel controller monitors the capacitance in the electrode regions to detect a change in the capacitance and upon the detection transmits a touch signal to said computer, and said computer receives the signal and executes a processing as previously programmed. 
         [0023]    The display system having a touch panel of the present invention can be practiced according to the preferable embodiment described below. 
         [0024]    (1) The system may further comprise a LAN (local area network) unit connected to a network, which receives a signal from said network and transmit the signal to said computer to make said computer execute a processing according to the signal. 
         [0025]    (2) The system may further comprise a load sensor mounted at the position where the touch panel is attached to the system, and also a load sensor controller. Said load sensor is electrically connected to said load sensor controller, said load sensor controller monitors the load received by said load sensor to detect a change in the load and upon the detection transmits a signal of the change in load to said computer, and said computer receives the signal and executes a processing as previously programmed. 
         [0026]    (3) The system may further comprise an audio amplifier and a speaker utilizing said touch panel as a diaphragm. The source of vibration for said speaker is mechanically connected to said touch panel and the output from said audio amplifier is input to the source of vibration to be produced into sound. 
         [0027]    The present invention, the preferred embodiments of the present invention, and the constituent elements include in them as described above may be embodied in other forms when they are combined to as much extent as possible. 
       ADVANTAGEOUS EFFECTS OF INVENTION 
       [0028]    The advantages of the curved touch panel of the present invention include the wide array of materials employable for the touch panel, because the touch panel is fabricated, among others, through the steps of forming a plurality of electrode regions with an electrically-conductive ink on a thermoplastic resin plate, heating to soften the plate and shaping the plate into the curved touch panel. 
         [0029]    The advantages of the method for fabricating the curved touch panel of the present invention include the applicability of the method to mass production and fabricating large touch panels and the facility of the method for fabricating curved touch panels of complicated curved surface shapes, because the method comprises, among others, the steps of forming an electrode layer on a thermoplastic resin plate to process it into a patterned plate, heating to soften the patterned plate, and shaping the softened patterned plate. 
         [0030]    The advantage of the display system having a touch panel of the present invention includes the wide application range of the system, because the touch panel comprises, among others, a thermoplastic resin which is resistant to an accidental shock. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0031]      FIG. 1  is the illustrative diagram of a display system having a touch panel. 
           [0032]      FIG. 2  is the illustrative diagram of a method for fabricating a touch panel, wherein  FIG. 2(   a ) is a plan view of a plate,  FIG. 2(   b ) is a plan view of a patterned plate,  FIG. 2(   c ) is an illustrative diagram of processing a soft curved product, and  FIG. 2(   d ) is a perspective view of a touch panel. 
           [0033]      FIG. 3  is the illustration of the electrode patterns of the touch panel having grid-partitioned detection parts (the second touch panel), and shows the overhead view of the second touch panel. 
           [0034]      FIG. 4  is the sectional view of the second touch panel. 
           [0035]      FIG. 5  is the process diagram illustrating the fabrication of the second touch panel. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0036]    Referring to the drawings, the touch panel, method for fabricating the touch panel and display system having the touch panel according to the embodiments of the present invention are further described. Some of the elements in the figures are magnified for easy understanding of the present invention. Thus some of the dimensions or dimensional ratio between the elements may be different from actual touch panels and display systems. The dimensions, materials, forms and relative positions of the members and parts described in the working examples of the present invention merely explain the present invention and do not intend to restrict the scope of the present invention unless otherwise specified. The numbers used as the signs may collectively represent parts, and an alphabetical letters is sometimes added to such numbers for representing each of such parts. 
         [0037]    The display system  1  having the touch panel includes an image projection unit  51 , a light-path-reflecting mirror  52 , and the touch panel  10 . The audiovisual memory unit  56  also functions as image memory unit and stores image data and audio data. The audiovisual controller  57  selectively pulls up image data from the audiovisual memory unit  56  and transmits the data to the image projection unit  51 . The image data can either be still-image data, moving image data or a mixture thereof. 
         [0038]    The image projection unit  51  converts the image data into an image and projects it. The image projection unit can be, for example, a unit with a transmissive liquid crystal panel, reflective liquid crystal panel or a DMD (digital micromirror device). 
         [0039]    The audiovisual controller  57  also functions as an audio amplifier. The audiovisual controller  57  converts audio data into sounds and voices and amplifies audio signals. The amplified audio signals are input to the speakers  58   a  and  58   b  and reproduced into sounds and voices with the speakers  58   a  and  58   b.    
         [0040]    The light-path-reflecting mirror  52  reflects an image projected from the image projection unit  51  and output the image to the touch panel  10 . The light-path-reflecting mirror  52  enables to avoid excessively long straight light path, which would be required in the display system  1  having the touch panel if the light path was not reflected with the light-path-reflecting mirror. The light-path-reflecting mirror is especially required for a display system with a large touch panel  10 , in which the distance between the rear side of the touch panel and the end of the display system becomes excessively large without the reflecting mirror. 
         [0041]    A convex mirror employed as the light-path-reflecting mirror  52  decreases the deformation in an image displayed on the touch panel  10 . The effect of decreasing the deformation is greater for a larger touch panel  10 . 
         [0042]    The touch panel  10  is a curve-surfaced product fabricated by forming a plurality of electrode regions of an electrically-conductive ink layer on a thermoplastic resin plate, heating and softening the plate to shape it into curved plate, and cooling or allowing to cool the shaped product. 
         [0043]      FIG. 2  is the illustrative diagram of a method for fabricating a touch panel. 
         [0044]    At first, a plate  11  was prepared referring to  FIG. 2(   a ). The plate  11  is made of a thermoplastic resin which softens with heat and hardens with cooling. The resin is solid at room temperature. The examples of the thermoplastic resins include acrylic resins, fluorine resins, polycarbonate resins, polyester resins, polystyrene resins, acrylonitrile-butadiene-styrene resins, polypropylene resins, polyacrylonitrile resins, polyamide resins, polyurethane resins and vinyl ester resins. 
         [0045]    The thickness of the plate  11  is not specifically restricted, and can be determined according to the dimension of the final product, a touch panel, and the properties of a resin to be employed. 
         [0046]    Electrode regions are formed on the plate  11  with an electrically-conductive ink. The electrically-conductive ink is made by mixing electrically-conductive particles in a binder. The examples of the electrically-conductive particles include carbon nanotube, silver nanofiber, copper nanofiber, and PEDOT (polyethylenedioxythiophene) which is an electrically-conductive, resin polymer particle. Of those nanoparticles, carbon nanotube makes an electrically-conductive ink of the lowest price, and contributes to lower price of the touch panel 
         [0047]    The shape of the electrically-conductive particles is granular or fiber-like. The dimensions of the fiber-like particles range usually from 1 nm (nanometer) to 100 nm and preferably from 5 nm to 50 nm in diameter, and usually from 10 nm to 1 mm (millimeter) and preferably from 50 nm to 500 pm (micrometer) in length. The dimension of the granular particles ranges usually from 1 nm to 100 nm and preferably from 5 nm to 50 nm in average diameter. 
         [0048]    The examples of the binder include acrylic resins, vinyl chloride resins, vinyl chloride-vinyl ester copolymer resins, EVA resins, polyurethane resins, polyacetate resins, chlorinated polypropylene resins and polyester resins. 
         [0049]    The ratio of electrically-conductive particles to a binder in an electrically-conductive ink ranges usually from 1 to 100 parts by weight and preferably from 2 to 95 parts by weight, to 100 parts by weight of the binder. The thickness of the resultant electrically-conductive ink layer ranges usually from 1 nm to 100 μm (micrometer), and preferably from 2 nm to 50 μm (micrometer). The sheet resistivity of the electrically-conductive ink layer ranges usually from 1 to 2000 ohm/sq. and preferably from 5 to 1000 ohm/sq. The transmittance of visible light through the electrically-conductive ink layer ranges usually from 1 to 100%, and preferably from 10 to 100%. 
         [0050]    On the plate  11 , a plurality of electrode regions are formed with an electrically-conductive ink. The electrode regions can be printed with gravure printing or screen printing. 
         [0051]    The electrode regions can also be formed with photolithography with either positive or negative type photoresist. An example of the procedure of the photolithography is as follows. 
         [0052]    (1) A photoresist covering the whole area of a plurality of electrode regions is applied onto the electrode regions with a coater or sprayer. 
         [0053]    (2) A continuous electrically-conductive ink layer is formed on the photoresist. The electrically-conductive ink layer can be applied onto the photoresist either continuously or discontinuously, for example, in a fine lattice pattern. Continuous coating can be implemented with a coater or sprayer, and coating in a fine lattice pattern can be implemented with a printing method such as gravure printing or screen printing. 
         [0054]    (3) The photoresist is exposed to ultraviolet lay, laser light or the like to form the electrode regions of an intended pattern. 
         [0055]    (4) The photoresist exposed to light is washed away in a solvent or the like and the electrically-conductive ink layer on the photoresist being washed away is lifted off. 
         [0056]    The electrode regions can be more precisely patterned with photolithography. 
         [0057]      FIG. 2(   b ) is a plan view of a patterned plate  13 . The electrode regions  15   a,    15   b  And  15   c  are patterned on one side of the patterned plate  13 . The lead wires  18   a,    18   b  and  18   c  are respectively extended from each of the electrode regions. This embodiment is an example of electrode regions patterned with photolithography. The profile lines of the electrode regions  15   a,    15   b  and  15   c  represent the cut lines  17  resulting from the lifting off. The cut lines  17  are noncurrent carrying parts. 
         [0058]    The regions of electrically-conductive ink layer are placed between electrode regions  15 . The regions of electrically-conductive ink layer are the reference electrode regions  16 . For example, the electrode region  16   g  exists between the electrode regions  15   a  and  15   b,  and the electrode region  16   h  exists between the electrode regions  15   b  and  15   c.    
         [0059]    The electrode regions  15 , reference electrode regions  16  and lead wires  18  on the patterned plate  13  are designed to make allowance for deformation and strain caused by mechanical stress in subsequent processes to shape curved surface shape. 
         [0060]    Then the patterned plate  13  is heated and softened. The plate is kept soft and shaped into curved surface shape on a die. The shaping can be carried out with pressure forming, vacuum forming or hot pressing, preferably with pressure forming or vacuum forming. 
         [0061]      FIG. 2(   c ) shows an example of pressure forming. Pressure is applied to the patterned plate on the die  22  in the direction indicated by the arrows in the figure and the patterned plate is shaped into a soft curved product  21 . 
         [0062]    When the patterned plate is shaped into the curved product, the electrode layers are deformed or strained due to tensile stress or compression stress. The electrically-conductive ink layer transforms along with such strain and the like, and keeps the electrical conductivity in the electrode regions unlike layers of specific metal oxides, such as ITO. 
         [0063]    The soft curved product  21  is allowed to cool. Then the unnecessary peripheral margin of the product is trimmed to make a curve-surfaced product, i.e., the touch panel  10 . In this embodiment, the touch panel  10  is shaped into hemispherical shape having a circular base of 150 mm (millimeter) in radius and a height of 200 mm from the base to the top. The plate is a 1.0 mm (one millimeter) thick acrylic resin plate. 
         [0064]    The touch panel  10  can be light-scattering or not. A light-scattering material is preferable for the touch panel  10  used as a screen for displaying projected image. An example of a light-scattering touch panel is a touch panel of the milky white acrylic resin plate  11 . 
         [0065]    A light-scattering material is not necessary for a touch panel to be incorporated in a touch-panel system which contains a screen solely used for displaying projected image, or for a touch panel to be incorporated in a touch-panel system which contains a liquid crystal display attached at the rear side of the touch panel. 
         [0066]    The touch panel  10  may either be colorless or colored. 
         [0067]    The display system  1  having a touch panel is explained again referring to  FIG. 1 . 
         [0068]    The touch panel  10  is a curve-surfaced product of a milky white thermoplastic resin plate. In other words, the touch panel  10  is made of a light-scattering resin. Image light projected from the image projection unit  51  is scattered by the touch panel  10  and an observer sees image on the touch panel. 
         [0069]    The lead wires  18  equipped with the touch panel are connected to the touch panel controller  54 . The touch panel controller  54  is a device to detect a touch by measuring variation of capacitance. The touch panel controller  54  has an oscillating circuit, decision circuit and signal generation circuit. The oscillating circuit generates variable oscillation frequency according to the capacitance values of the electrode regions. The decision circuit detects a change in the oscillation frequency. The signal generation circuit transmits a touch signal to the computer  53  when the decision circuit detects a change in the oscillation frequency. The capacitance values of the electrode regions are derived from a comparative calculation with the capacitance values of the reference electrode regions. 
         [0070]    When the touch panel  10  is separate from a human finger, the capacitance values of the electrode regions are kept at a constant value, and the oscillating circuit generates a constant oscillation frequency. When a human finger comes close to or contacts electrode regions of the touch panel  10 , the capacitance of the electrode regions changes to change the oscillation frequency, and the decision circuit detects the change in the oscillation frequency. Then the signal generation circuit transmits the touch signal to the computer  53  and the computed  53  receives the touch signal to execute a task previously programmed. Examples of the previously programmed tasks include selecting projected images, scaling the images, selecting sounds, controlling volume, and turning on or off the display system  1  having a touch panel. 
         [0071]    The computer  53  controls the units and parts mentioned above and also controls the whole system of the display system  1  having a touch panel. 
         [0072]    The display system  1  having a touch panel can include a LAN controller  55 . The LAN controller  55  is connected to a LAN. The LAN controller  55  functions to take in image data and audio data stored in the audiovisual memory unit  56 , replace the data, change the program in the computer  53 , perform remote maintenance, and play back contents from internet broadcasting. 
         [0073]    The display system  1  having a touch panel can have a load sensor at the attaching position  61  of the touch panel  10  and have a load sensor controller connected to the computer  53 . The load sensor is electrically connected to the load sensor controller. The display system preferably has a plurality of load sensors, because a single load sensor senses a change in load caused by a touch with a finger on the touch panel  10  and determines the change in load simultaneously as a touch and a push. 
         [0074]    The load sensor detects a change in load caused by pushing the touch panel  10  and changes the quantity of the load signal transmitted to the load sensor controller which determines the change in the quantity of the load signal and transmits a changed-load sensing signal to the computer  53 . The changed-load sensing signal should preferably be transmitted after calculating the change in the quantity of load signals from a plurality of load sensors, for the purpose of determining, for example, the direction of a push on the touch panel  10 . The function enables the touch panel  10  to be used as an input device like a joystick. 
         [0075]    The computer  53  receives the changed-load sensing signal and executes a task previously programmed. 
         [0076]    The touch panel  10  can also function as a diaphragm of a speaker. A large curved touch panel fabricated according to the present invention can be a large diaphragm which implements megavolume and high-quality sound. Thus a diaphragm of a speaker is a preferable application of the touch panel of the present invention. 
         [0077]    The examples of the source of vibration for the speaker include:
       (1) permanent magnet and voice coil, and   (2) piezoelectric element       
 
         [0080]    In other words, the display system  1  having a touch panel can include permanent magnet and voice coil. The voice coil is arranged close to the permanent magnet, preferably in a cylinder of permanent magnet. The output from the audio amplifier in the audiovisual controller  57  is input to the voice coil. The voice coil is mechanically connected to the touch panel  10 . Thus the touch panel  10  functions as a diaphragm of a speaker. 
         [0081]    A piezoelectric element used as the source of vibration for a speaker is mechanically connected to the touch panel  10 . The output from the audio amplifier in the audiovisual controller  57  is input to the piezoelectric element, and the touch panel  10  functions as a diaphragm as mentioned above. 
         [0082]    The touch panel  10  described above has a single electrode layer which is divided into sector-shaped electrode regions arranged along the longitude lines of the hemisphere-shaped touch panel. The terms, longitude lines and latitude lines, in the present invention mean the longitude lines and latitude lines defined with the pole positioned at the top of the hemispherical touch panel  10  and the equator positioned at the attaching position  61  of the touch panel to the display system  1  having a touch panel. When the touch panel  10  is incorporated into an input unit for the touch panel, touching to the touch panel is detected by each of the electrode regions mentioned above. 
         [0083]    The touch panel of the present invention can have a plurality of electrode layers which are formed into grid-partitioned detection parts. An example of the grid partitioning is the grids sectioned along the longitude lines and latitude lines of the hemispherical touch panel. 
         [0084]      FIG. 3  is the illustration of the electrode patterns of the touch panel having grid-partitioned detection parts (the second touch panel), and shows the overhead view of the second touch panel  110 . 
         [0085]      FIG. 4  is the sectional view of the touch panel having grid-partitioned detection parts formed with the electrode layers disposed on both sides of the panel (the second touch panel).  FIG. 5  is the process diagram illustrating the fabrication of the second touch panel. 
         [0086]      FIG. 3(   a ) shows the pattern of the electrode regions  15  at the first electrode layer  14  and  FIG. 3(   b ) shows the pattern of the electrode regions  115  at the second electrode layer  114 . The pattern of the electrode regions at the first electrode layer  14  is the same as the pattern of the electrode layer of the touch panel  10 . Each of the electrode regions  15  extends along the latitude lines. The electrode regions  15   a ,  15   b  and  15   c,  the lead wires  18   a,    18   b  and  18   c,  and the reference electrode regions  16   a ,  16   b  and  16   c  are marked with the same signs as those for the figure illustrating the touch panel  10 . 
         [0087]    The electrode regions patterned in the second electrode layer  114  are designed into concentric circles of  115   a,    115   b  and  115   c,  and the lead wires  118   a,    118   b  and  118   c  are extended from each of the electrode regions  115   a,    115   b  and  115   c  to the base of the hemispherical touch panel. The electrically-conductive ink layer is cut at the cut lines  117 . The reference electrode regions  116   a,    116   b  and  116   c  exist between the electrode regions  115   a,    115   b  and  115   c.  The electrode regions patterned in the second electrode layer extend along the latitude lines of the hemispherical touch panel. 
         [0088]    Referring to  FIG. 4 , the second electrode layer  114  is superposed over the first electrode layer  14  without direct contact by forming the first electrode layer  14  on the rear side of the plate  11  and forming the second electrode layer  114  on the front side of the plate  11 , and thus the second touch panel  110  is produced. 
         [0089]    The method for fabricating the second touch panel  110  is briefly explained referring to  FIG. 5 . The method for fabricating the second touch panel  110  is almost the same as the method for fabricating the touch panel  10 . Thus only the difference in the methods is mentioned here. 
         [0090]    At first, electrically-conductive ink layers  23  and  123  are formed on the rear and front sides of the plate  11  with coating or other means ( FIG. 5(   a )). 
         [0091]    Then the electrically-conductive ink layer  23  on the rear side is formed into the pattern of the first electrode layer  14 , and the electrically-conductive ink layer  123  on the front side is formed into the pattern of the second electrode layer  114  to prepare the patterned plate ( FIG. 5(   b )). 
         [0092]    The patterned plate is heated, shaped and cooled or allowed to cool ( FIG. 5(   c )). 
         [0093]    Finally, a protective layer is formed onto the second electrode layer  114  to be processed into the touch surface. The examples of the materials for the protective layer include activation-energy-curable resins which are curable with ultraviolet ray or electron beam and represented by light-curable resins such as UV-curable resins and radiation-curable resins such as electron-beam-curable resins; and thermosetting and activation-energy-curable resins. 
         [0094]    The second touch panel having the first electrode layer and the second electrode layer respectively formed on each side of the base material has been described above as an example of a touch panel having grid-partitioned detection parts. Similar touch panels can be fabricated by laminating two plates prepared by forming the first electrode layer on one side of a substrate and forming the second electrode layer on one side of another substrate. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1  Display system having a touch panel 
           10  Touch panel 
           11  Plate 
           13  Patterned plate 
           14  First electrode layer 
           15  Electrode region (along longitude lines) 
           16  Reference electrode region (along longitude lines) 
           17  Cut line (noncurrent carrying part) 
           18  Lead wire 
           19  Protective layer 
           21  Soft curved product 
           22  Die 
           51  Image projection unit 
           52  Light-path reflecting mirror 
           53  Computer 
           54  Touch panel controller 
           55  LAN unit 
           56  Audiovisual memory unit also functioning as an image memory unit 
           57  Audiovisual controller also functioning as an audio amplifier 
           58  Speaker 
           61  Attaching position 
           110  Second touch panel (touch panel having grid-patterned detection parts) 
           114  Second electrode layer 
           115  Electrode region (along longitude lines) 
           116  Reference electrode region (along latitude lines) 
           117  Cut line (noncurrent carrying part) 
           118  Lead wire