JP2014096061A - Touch panel, and manufacturing method of touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of failure of a sensor function caused by disconnection in forming a curved shape in a three-dimensional curved face touch panel.SOLUTION: A touch panel 1 includes a base material sheet 3, a first electrode layer 5 and a second electrode layer 7 made of a conductive ink, and a buffer layer 9. The base material sheet 3 has a three-dimensional shape. The first electrode layer 5 and second electrode layer 7 are formed on the base material sheet 3. The buffer layer 9 is formed on the base material sheet 3 to cover at least a part of the first electrode layer 5 and second electrode layer 7, and includes a porous rubber-like member.

Description

  The present invention relates to a touch panel, and particularly to a touch panel provided with a three-dimensional shape.

Conventionally, a capacitive touch panel having a three-dimensional curved touch surface and a light scattering layer provided on the back surface is known (see, for example, Patent Document 1).
In a conventional touch panel, an electrode for detecting presence or absence of a touch is a transparent conductive film formed of a specific metal oxide such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), SnO 2 (Tin Oxide), etc. Consists of. This conductive film is formed by vacuum plating such as sputtering.

  In addition, the touch panel normally detects a touch position, and there are a plurality of electrodes formed on the touch surface, and it is necessary to form a plurality of electrodes with high accuracy.

  However, a curved touch panel with a specific metal oxide film formed on a curved substrate requires vacuum plating, so the material is a material that can withstand vacuum plating such as soda glass, borosilicate glass, and heat resistant glass. There are limited drawbacks.

  Moreover, since the conventional manufacturing method of a curved touch panel employs vacuum plating, it is not suitable for mass production, and if the touch panel is enlarged, the manufacturing becomes difficult. Furthermore, when the touch panel has a complicated three-dimensional curved surface shape, there is a drawback that it is difficult to accurately form a plurality of electrodes.

  Therefore, in order to solve these drawbacks, a three-dimensional curved surface created by forming a plurality of electrode regions on a flat plate made of thermoplastic resin using conductive ink, and heating and softening the electrode regions. A touch panel has been previously proposed by the present applicant (a known document cannot be indicated because the previous application has not been published).

Specifically, a capacitive touch panel having a three-dimensional curved touch surface is manufactured by the following steps.
First, a flat plate made of thermoplastic resin is prepared.
Next, the drawing flat plate is created by forming an electrode layer having a plurality of electrode regions on the flat plate using a conductive ink composed of a conductive substance and a binder.
Further, the preform is executed by vacuum / pressure forming.
Finally, the curved substrate is integrated with the housing by vacuum bonding or insert molding.
The conductive ink is an ink in which a conductive substance is mixed in a binder. Examples of the conductive substance include carbon nanotubes, silver nanofibers, copper nanofibers, and PEDOT (polyethylenedioxythiophene) which is a conductive resin polymer.

  This proposal has an advantage that more materials can be selected as a three-dimensional curved touch panel. Further, as a method for manufacturing a three-dimensional curved touch panel, there is an advantage that it is suitable for mass production, can be directly applied to a large product, and can be easily produced even with a complicated curved shape.

JP 2007-279819 A

  In the improved technique, the electrode formed of the conductive ink extends from the curved portion of the base sheet to the flat portion, and has an electrode extraction site in the flat portion of the base sheet. A routing circuit layer is connected to the end of the electrode lead-out portion.

  However, at the time of injection molding, the flat portion of the base sheet is strongly sandwiched between the molds, so that the impact causes a disconnection at the electrode extraction site (which means that the resistance value increases due to damage to the electrode layer, etc. The same applies hereinafter). It is expected that it will occur easily. In particular, conductive ink has a problem of low resistance to impact.

In addition, since the conductive ink is poor in stretchability, it is easy to break at the peripheral portion (the rising portion of the curved surface) in the three-dimensional curved surface where the elongation becomes maximum at the time of vacuum pressure forming.
As a result, the 3D curved touch panel may not react at all as a sensor, or even if it reacts, the sensitivity may be extremely deteriorated.

  Therefore, the subject of this invention is making it difficult to produce the malfunction of the sensor function resulting from the disconnection at the time of forming a curved-surface shape in a three-dimensional curved-surface touch panel.

  Hereinafter, a plurality of modes will be described as means for solving the problems. These aspects can be arbitrarily combined as necessary.

A touch panel according to an aspect of the present invention includes a base sheet, an electrode made of conductive ink, and a buffer layer. A three-dimensional shape is given to the base material sheet. The electrode is formed on the base sheet. The buffer layer is formed on the base sheet so as to cover at least a part of the electrode, and includes a porous rubber-like member.
In this touch panel, since the buffer layer is formed on the electrode, the impact on the electrode is reduced in the step of imparting a three-dimensional shape to the base sheet. Therefore, disconnection is unlikely to occur in the electrode.

The buffer layer may contain conductive particles.
In this touch panel, even when the electrode is disconnected, the conductive state is ensured by the conductive particles.

Even if the buffer layer is formed at least on the electrode from the vicinity of the boundary between the flat portion and the curved portion formed by bending the base sheet in the step of imparting the three-dimensional shape to the edge of the flat portion. Good.
In this touch panel, when the flat part of the base sheet is strongly sandwiched between the molds by injection molding, the shock is alleviated by the buffer layer. Therefore, disconnection is unlikely to occur in the electrode.

The touch panel further includes conductive particles contained in the buffer layer,
In the buffer layer, the conductive particles may be included in a region corresponding to a portion close to the flat portion of the curved portion of the base sheet.
In this touch panel, conductive particles are provided at locations where electrode disconnection is likely to occur.

  The porous rubber-like member may contain at least a thermoplastic resin or a thermoplastic elastomer and a crosslinkable elastomer as a rubber-like member forming composition.

The touch panel manufacturing method according to another aspect of the present invention includes the following steps.
◎ Forming an electrode made of conductive ink on the base sheet ◎ Forming a buffer layer containing a porous rubber-like member on the base sheet so as to cover at least a part of the electrode ◎ Electrode layer In this touch panel, since the buffer layer is formed on the electrode, in the step of providing the three-dimensional shape to the base sheet, the electrode is applied to the base sheet on which the buffer layer is formed. Impact is alleviated. Therefore, disconnection is unlikely to occur in the electrode.

  In the touch panel according to the present invention, it is difficult to cause a malfunction of the sensor function due to disconnection when forming a curved surface shape.

1 is a plan view of a three-dimensional curved touch panel according to a first embodiment. It is II-II sectional drawing of FIG. It is a schematic diagram explaining the process of pattern-printing a some material on a base material sheet. It is a schematic diagram for demonstrating a general vacuum pressure forming technique. It is a schematic diagram for demonstrating a general injection molding technique. It is a schematic diagram explaining the process of providing the three-dimensional shape by vacuum pressure forming and injection molding. It is a top view of the three-dimensional curved surface touch panel which concerns on 2nd Embodiment. It is VIII-VIII sectional drawing of FIG. It is a schematic diagram explaining the process of pattern-printing a some material on a base material sheet. It is a schematic diagram explaining the process of providing the three-dimensional shape by vacuum pressure forming and injection molding. It is a top view of the touch panel concerning the 1st reference example. It is XII-XII sectional drawing of FIG. It is XIII-XIII sectional drawing of FIG. It is a top view of the touch panel which concerns on a 2nd reference example. It is XV-XV sectional drawing of FIG. It is XVI-XVI sectional drawing of FIG. It is sectional drawing of the three-dimensional curved surface touchscreen which concerns on 3rd Embodiment. It is a schematic diagram explaining the process of pattern-printing a some material on a base material sheet. It is a schematic diagram explaining the process of providing the three-dimensional shape by vacuum pressure forming and injection molding. It is sectional drawing of the three-dimensional curved surface touchscreen which concerns on 4th Embodiment. It is a schematic diagram explaining the process of pattern-printing a some material on a base material sheet. It is a schematic diagram explaining the process of providing the three-dimensional shape by vacuum pressure forming and injection molding. It is sectional drawing of the three-dimensional curved surface touchscreen which concerns on 5th Embodiment. It is a schematic diagram explaining the process of pattern-printing a some material on a base material sheet. It is a schematic diagram explaining the process of providing the three-dimensional shape by vacuum pressure forming and injection molding. It is sectional drawing of the three-dimensional curved surface touchscreen which concerns on 6th Embodiment. It is a schematic diagram explaining the process of pattern-printing a some material on a base material sheet. It is a schematic diagram explaining the process of providing the three-dimensional shape by vacuum pressure forming and injection molding.

  Hereinafter, a three-dimensional curved touch panel and an electronic device casing using the same according to an embodiment of the present invention will be described with reference to the drawings. In addition, in each figure referred below, in order to make an understanding easy, some components are expressed exaggeratedly.

1. First Embodiment (1) Structure of Touch Panel The structure of the touch panel 1 will be described with reference to FIGS. 1 and 2.
FIG. 1 is a plan view of a three-dimensional curved touch panel, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

  The touch panel 1 is a single-sided single layer sensor type. The touch panel 1 (an example of a touch panel) mainly includes a base material sheet 3 (an example of a base material sheet), a first electrode layer 5 and a second electrode layer 7 (an example of an electrode layer), and a buffer layer 9 (a buffer layer). And a transparent cover layer 11. Schematically, the first electrode layer 5 and the second electrode layer 7 are formed on the upper surface of the base material sheet 3, and the buffer layer 9 is disposed on the upper surface of the base material sheet 3, and a transparent cover is provided on the buffer layer 9. Layer 11 is disposed. In this embodiment, the buffer layer 9 is formed on almost the entire top surface of the base sheet 3.

  In FIG. 1, another device for configuring an electronic device casing together with the touch panel 1 is disclosed. Other devices are, for example, an LED 41 as a light emitting unit and an LCD 43 as an image display unit. The LED 41 is provided on a curved plate similarly to the base sheet 3. The LCD 43 is disposed on the opposite side of the LED 41 from the touch panel 1 side.

  As is clear from FIG. 2, the base sheet 3 has a circular hemispherical curved portion 17 (an example of a curved portion) in a plan view, and a flat portion 19 (an example of a flat portion) therearound. ing. An arc-shaped boundary 21 is formed at the boundary between the curved portion 17 and the flat portion 19. In this embodiment, for example, the radius of the bottom surface of the curved portion 17 is 150 mm, and the distance from the bottom surface of the curved portion 17 to the top portion is 200 mm.

  The base material sheet 3 and the transparent cover layer 11 are made of a transparent thermoplastic resin, and are softened by heating and solidified by cooling. That is, it is in a solidified state at room temperature. Thermoplastic resins include, for example, acrylic resins, fluorine resins, polycarbonate resins, polyester resins, polystyrene resins, acrylonitrile-butadiene-styrene resins, polypropylene resins, polyacrylonitrile resins, polyamide resins, urethane resins. Examples thereof include resins and vinyl ester resins.

A hard coat layer may be formed on the upper surface of the transparent cover layer 11. Examples of the hard coat layer include inorganic materials such as siloxane-based resins, and organic materials such as acrylic epoxy-based and urethane-based thermosetting resins and acrylate-based photocurable resins.
The thicknesses of the base material sheet 3 and the transparent cover layer 11 are not particularly limited, and may be determined in consideration of the dimensions of the finished three-dimensional curved touch panel, the properties of the resin used, and the like.

  The first electrode layer 5 and the second electrode layer 7 are formed on the surface of the base sheet 3 using a conductive ink having excellent transparency. The first electrode layer 5 has a circular shape formed at the center of the curved portion 17 of the base sheet 3. The second electrode layer 7 has a plurality of strips arranged radially around the first electrode layer 5. As is apparent from FIG. 2, the second electrode layer 7 extends from the flat portion 19 of the base sheet 3 to the outer peripheral portion of the curved portion 17 through the boundary 21. More specifically, the second electrode layer 7 has a curved portion corresponding portion 7a and a flat portion corresponding portion 7b. The bending portion 17 side of the bending portion corresponding portion 7 a is an end portion 7 c that is cut in the middle of the bending portion 17.

  The conductive ink used to form the first electrode layer 5 and the second electrode layer 7 is, for example, polyethylene dioxythiophene (PEDOT) or carbon nanotube (CNT).

  The formation of the first electrode layer 5 and the second electrode layer 7 on the surface of the base sheet 3 is performed by gravure printing or screen printing. The formation of the first electrode layer 5 and the second electrode layer 7 may be performed by photolithography. The resist used may be either a positive type or a negative type.

  A routing circuit layer 13 is connected to the first electrode layer 5 and the second electrode layer 7. The routing circuit layer 13 is connected to an FPC (Flexible printed circuit) 15 disposed on the edge of the base sheet 3. The routing circuit layer 13 is made of a material in which a conductive filler is dispersed in a binder. For example, a polyester resin is used as the binder, and silver powder is used as the conductive filler.

  The FPC 15 is connected to a touch panel control unit (not shown). The touch panel control unit is a device part that realizes capacitive touch detection, and includes an oscillation circuit, a determination circuit, and a signal transmission circuit. The oscillation frequency of the oscillation circuit changes according to the capacitance value of the main electrode region. The determination circuit determines whether or not the oscillation frequency has changed. The signal transmission circuit transmits a touch signal to the computer when the determination circuit detects a change in the oscillation frequency.

  When the touch panel 1 is separated from a human finger or the like, the capacitance value of the main electrode region is constant, and the oscillation circuit oscillates at a constant oscillation frequency. When a human finger approaches or comes into contact with the main electrode region of the touch panel 1, the capacitance of the main electrode region changes, and thereby the oscillation frequency changes. The determination circuit detects the change. When the signal transmission circuit sends the touch signal to the computer, the computer receives the touch signal and executes a predetermined task. Examples of the predetermined tasks include switching of a projected image, enlargement / reduction, switching of sound, volume of sound, turning on / off a display device with a curved touch panel, and the like.

The buffer layer 9 has a central portion 9a, an outer peripheral portion 9b, and a flat portion 9c. The central portion 9 a and the outer peripheral portion 9 b correspond to the curved portion 17 of the base sheet 3.
The buffer layer 9 is composed of a porous rubber-like member. The porous rubber-like member is a member containing a thermoplastic resin or a thermoplastic elastomer and a crosslinkable elastomer. The thermoplastic resin is, for example, polypropylene PP, polyethylene PE, ethylene / vinyl acetate copolymer EVA. The thermoplastic elastomer is, for example, a styrene elastomer, an olefin elastomer, or a polyester elastomer. The crosslinkable elastomer is, for example, styrene-butadiene rubber SBR.

The mixing ratio and weight ratio of the thermoplastic resin or thermoplastic elastomer and the crosslinkable elastomer are usually 70:30 to 95: 5, preferably 75:25 to 90:10.
The thickness of the buffer layer 9 is usually 1 nm to 100 μm, preferably 2 nm to 50 μm.
The visible light transmittance of the buffer layer 9 is usually 80% to 85%, preferably 85% to 90%.

The buffer layer 9 further includes conductive particles 25 (an example of conductive particles). The conductive particles 25 are made of metal (nickel or a nickel-coated composite material), or a plastic or resin core that is metal-plated. The conductive particles 25 may have a shape that does not contact an adjacent electrode and the number of dispersions as long as the conductive particles 25 exhibit stable electrical conductivity between the opposing electrodes.
In this embodiment, the conductive particles 25 are partially arranged in the buffer layer 9. Specifically, the conductive particles 25 in the buffer layer 9 correspond to a portion (specifically, the outer peripheral portion of the curved portion 17) of the curved portion 17 of the base sheet 3 that is close to the flat portion 19 (specifically, the outer peripheral portion of the curved portion 17). It is included in the outer peripheral portion 9b) of the buffer layer 9. This is because this region corresponds to the peripheral portion (the rising portion of the curved surface) within the three-dimensional curved surface where the elongation of the base sheet 3 is maximized.

(2) Manufacturing method of touch panel The manufacturing method of the touch panel 1 is demonstrated using FIGS. FIG. 3 is a schematic cross-sectional view showing a process of forming various layers on the base sheet. FIG. 4 is a schematic diagram for explaining a general vacuum / pressure forming technique. FIG. 5 is a schematic diagram for explaining a general injection molding technique. FIG. 6 is a schematic diagram for explaining a process for imparting a three-dimensional shape by vacuum / pressure forming and injection molding.

  First, as shown to Fig.3 (a), the conductive ink used as the 1st electrode layer 5 and the 2nd electrode layer 7 is pattern-printed on the base material sheet 3. FIG. Further, as shown in FIG. 3 (b), a silver paste to be the routing circuit layer 13 is pattern printed on the base sheet 3. Such pattern printing is performed by, for example, screen printing or laser processing. Finally, as shown in FIG. 3C, the buffer layer 9 is screen-printed on almost the entire upper surface of the base sheet 3.

Furthermore, temporary adhesion is performed by thermally laminating an adhesive sheet on the base sheet 3. Thereafter, a release sheet is placed on the adhesive sheet side.
Further, as shown in FIG. 4, a preform is formed by vacuum / pressure forming. First, as shown in FIG. 4A, the mold 33 is raised with respect to the base sheet 3 while heating the base sheet 3 with the heater 31. Then, as shown in FIG. 4B, the base sheet 3 is stretched. Furthermore, as shown in FIG.4 (c), it shape | molds by performing pressure air, drawing a vacuum. Finally, as shown in FIG. 4 (d), the mold 33 is lowered to release the mold.
As a result, a preformed base sheet 3 is obtained as shown in FIG.

Next, the resin flat plate which becomes the transparent cover layer 11 is bonded to the preformed base sheet 3 and heat-cured to perform the main adhesion. As a result, the touch panel 1 is completed as shown in FIG.
For the formation of the transparent cover layer 11, injection molding is used in addition to the bonding. In the injection molding, as shown in FIG. 5, the preformed base sheet 3 is inserted into the molding dies 35 and 37, the molds 35 and 37 are closed, and then the molten resin that becomes the transparent cover layer 11 is filled. To do. Finally, the touch panel 1 is completed.
In the above embodiment, vacuum / pressure forming is used for the preform, but other methods may be used. For example, pressure forming, vacuum forming, or hot press forming may be used.

  During the preform processing described above, the base sheet 3 is deformed from a flat shape to have a three-dimensional curved surface. Specifically, the base sheet 3 is subjected to a force toward the mold 33 in FIGS. 4B and 4C in the state of being heated and softened in FIG. Deforms along 33 three-dimensional curved surface. At this time, the amount of extension within the same three-dimensional curved surface differs depending on the location, and the peripheral edge within the three-dimensional curved surface is particularly greatly extended.

  In this touch panel, since the buffer layer 9 is formed on the second electrode layer 7, the impact on the second electrode layer 7 is alleviated in the step of imparting a three-dimensional shape to the base sheet 3. Accordingly, disconnection is unlikely to occur in the second electrode layer 7. Specifically, the buffer layer 9 extends from the vicinity of the boundary 21 between the flat portion 19 and the curved portion 17 formed by bending the base sheet 3 in the step of providing a three-dimensional shape to the edge of the flat portion 19. At least formed on the second electrode layer 7. Therefore, as shown in FIG. 5, when the flat part 19 of the base sheet 3 is strongly sandwiched between the molds 35 and 37 by injection molding, the shock is mitigated by the buffer layer 9 (specifically, the flat part 9c). The Accordingly, disconnection is unlikely to occur in the second electrode layer 7.

  Furthermore, since the buffer layer 9 includes the conductive particles 25, the conductive state is easily ensured by the conductive particles 25 even when the second electrode layer 7 is disconnected. Specifically, in this embodiment, the buffer layer 9 covers the entire first electrode layer 5 and the second electrode layer 7, and the conductive particles 25 are separated from the boundary 21 of the base sheet 3 in the buffer layer 9. The second electrode layer 7 is included in a region between the end portion 7 c in the curved portion 17 (specifically, the outer peripheral portion 9 b of the buffer layer 9). That is, in this embodiment, the conductive particles 25 are provided only at the locations where the disconnection of the second electrode layer 7 is likely to occur.

2. Second Embodiment A touch panel 101 according to a second embodiment will be described with reference to FIGS. Note that description of the same parts as those in the first embodiment is omitted.
In this embodiment, the buffer layer 109 is formed corresponding to only the outer peripheral portion of the curved portion 117 and the flat portion 119 of the base sheet 103. That is, the buffer layer 109 is formed in an annular shape with a predetermined width as shown in FIGS. Therefore, a space 115 is secured between the base sheet 103 and the transparent cover layer 111 in the vicinity of the center of the curved portion 117 of the base sheet 103.

  In the buffer layer 109, the conductive particles 125 are provided only on the outer peripheral portion 109b of the buffer layer 109 as shown in FIG. That is, in this embodiment, the conductive particles 125 are provided only at the locations where the disconnection of the second electrode layer 107 is likely to occur.

3. First Reference Example A reference example for describing another embodiment of the present invention will be described with reference to FIGS.
The touch panel 201 is a single-sided two-layer sensor type and has a diamond-like electrode.
The touch panel 1 includes a base sheet 203, an X electrode layer 205 and a Y electrode layer 207, and a buffer layer 9.

The X electrode layer 205 is formed extending in the left-right direction in FIG. The Y electrode layer 207 is formed extending in the vertical direction of FIG. As a result, both electrode layers are alternately arranged.
As shown in FIGS. 12 and 13, the X electrode layer 205 is formed on the base sheet 203. The X electrode layer 205 is covered with an insulating layer 206. The Y electrode layer 207 is formed on the base sheet 203 in a state insulated from the X electrode layer 205 by the insulating layer 206.
The buffer layer 209 covers the entire region where the X electrode layer 205 and the Y electrode layer 207 are formed on the base sheet 203.

4). Second Reference Example A reference example for explaining another embodiment of the present invention will be described with reference to FIGS.
In this reference example, unlike the third embodiment, the buffer layer 209 is partially formed with respect to the base sheet 203. Specifically, a space 210 in which the buffer layer 209 is not formed is secured in the base sheet 203.

5. Third Embodiment (1) Structure of Touch Panel The structure of the touch panel 301 will be described with reference to FIG. A description of the same points as in the first embodiment will be omitted.
The touch panel 301 is a single-sided two-layer sensor type. The touch panel 301 mainly includes a base sheet 303, an X electrode layer 305 and a Y electrode layer 307, a buffer layer 309, and a transparent cover layer 311.

  The base sheet 303 has a circular hemispherical curved portion 317 in plan view and a flat portion 319 around the curved portion 317. An arc-shaped boundary 321 is formed at the boundary between the curved portion 317 and the flat portion 319.

  The base sheet 303 and the transparent cover layer 311 are made of a transparent thermoplastic resin, and are softened by heating and solidified by cooling.

The X electrode layer 305 and the Y electrode layer 307 are formed on the surface of the base sheet 303 using a conductive ink having excellent transparency. The X electrode layer 305 is a diamond-like electrode formed on the base sheet 303 as shown in the first reference example (FIG. 11). The Y electrode layer 307 is a diamond-like electrode formed on the base sheet 303 as shown in the first reference example (FIG. 11).
The X electrode layer 305 is formed extending in the left-right direction in FIG. The Y electrode layer 307 is formed to extend in the direction perpendicular to the paper surface of FIG. As a result, both electrode layers are alternately arranged.

The X electrode layer 305 is formed on the base material sheet 303. The X electrode layer 305 is covered with an insulating layer 306. The Y electrode layer 307 is formed on the base material sheet 303 in a state insulated from the X electrode layer 305 by the insulating layer 306.
As shown in FIG. 17, the X electrode layer 305 passes from the flat portion 319 of the base sheet 303 through the boundary 321 to the curved portion 317, and further to the opposite flat portion 319 via the opposite boundary 321. It extends. More specifically, the X electrode layer 305 has a curved portion corresponding portion 305a and a flat portion corresponding portion 305b. Note that the above description of the X electrode layer 305 also applies to the Y electrode layer 307.

  The conductive ink used to form the X electrode layer 305 and the Y electrode layer 307 is, for example, polyethylene dioxythiophene (PEDOT) or carbon nanotube (CNT).

  The buffer layer 309 has a central portion 309a, an outer peripheral portion 309b, and a flat portion 309c. The central part 309 a and the outer peripheral part 309 b correspond to the curved part 317 of the base sheet 303.

The buffer layer 309 further includes conductive particles 325.
In this embodiment, the conductive particles 325 are partially disposed in the buffer layer 309. Specifically, the conductive particles 325 have a region (specifically, an outer peripheral portion of the curved portion 317) corresponding to a portion of the curved portion 317 of the base sheet 303 that is close to the flat portion 319 in the buffer layer 309 (specifically, the outer peripheral portion of the curved portion 317). The outer peripheral portion 309b) of the buffer layer 309 is included. This is because this position corresponds to the peripheral portion (the rising portion of the curved surface) in the three-dimensional curved surface where the elongation is maximum.

(2) Manufacturing method of touch panel The manufacturing method of the touch panel 301 is demonstrated using FIGS.
First, as shown in FIG. 18A, a conductive ink to be the X electrode layer 305 is pattern-printed on the base sheet 303. Next, as shown in FIG. 18B, the insulating layer 306 is pattern-printed on the upper surface of the base material sheet 303. Further, as shown in FIG. 18C, the conductive ink to be the Y electrode layer 307 is printed on the base sheet 303 in a pattern. Further, as shown in FIG. 18 (d), a silver paste to be the routing circuit layer 313 is pattern-printed. Finally, as shown in FIG. 18 (e), the buffer layer 309 is screen-printed on the entire base sheet 303.

Furthermore, temporary adhesion is performed by thermally laminating an adhesive sheet on the base sheet 303. Thereafter, a release sheet is placed on the adhesive sheet side.
Further, a preform is formed by vacuum / pressure forming. As a result, a preformed base sheet 303 is obtained as shown in FIG.

  Next, the resin flat plate which becomes the transparent cover layer 311 is bonded to the preformed base material sheet 303, and this bonding is performed by heat curing. As a result, the touch panel 301 is completed as shown in FIG. As a method of forming the transparent cover layer 311, injection molding is used in addition to bonding.

6). 4. Fourth Embodiment (1) Touch Panel Structure A touch panel 301 according to a fourth embodiment will be described with reference to FIGS. A description of the same parts as in the above embodiment will be omitted.
In this embodiment, the buffer layer 309 is formed corresponding to only the outer peripheral portion of the curved portion 317 and the flat portion 319 of the base sheet 303. That is, the buffer layer 309 is formed in an annular shape with a predetermined width. Therefore, in the vicinity of the center of the curved portion 317 of the base sheet 303, a space 315 is secured between the base sheet 303 and the transparent cover layer 311 (shown in FIGS. 14 to 16 of the second reference example). See space 210).

In this embodiment, the conductive particles 325 are partially disposed in the buffer layer 309. Specifically, the conductive particles 325 have a region (specifically, an outer peripheral portion of the curved portion 317) corresponding to a portion of the curved portion 317 of the base sheet 303 that is close to the flat portion 319 in the buffer layer 309 (specifically, the outer peripheral portion of the curved portion 317). The outer peripheral portion 309b) of the buffer layer 309 is included. This is because this region corresponds to the peripheral portion (the rising portion of the curved surface) in the three-dimensional curved surface where the elongation of the base sheet 303 is maximized.
21 and 22 correspond to the description of FIGS. 18 and 19 of the third embodiment, and thus the description thereof is omitted.

7). Fifth Embodiment (1) Touch Panel Structure A touch panel 401 according to a fifth embodiment will be described with reference to FIGS. A description of the same points as in the above embodiment will be omitted.
The touch panel 401 is a double-sided single-layer sensor type. The touch panel 401 mainly includes a base sheet 403, an X electrode layer 405 and a Y electrode layer 407, a first buffer layer 409A and a second buffer layer 409B, and a transparent cover layer 411.

  The base material sheet 403 includes a circular hemispherical curved portion 417 in a plan view and a flat portion 419 therearound. An arc-shaped boundary 421 is formed at the boundary between the curved portion 417 and the flat portion 419.

  The base sheet 403 and the transparent cover layer 411 are made of a transparent thermoplastic resin, and are softened by heating and solidified by cooling.

The X electrode layer 405 and the Y electrode layer 407 are formed on the surface of the base material sheet 403 using a conductive ink having excellent transparency. The X electrode layer 405 is formed on the upper surface of the base material sheet 403. The X electrode layer 405 is a diamond-like electrode formed on the base sheet 403. The Y electrode layer 407 is formed on the lower surface of the base sheet 403. The Y electrode layer 407 is a diamond-like electrode formed on the base sheet 403.
The X electrode layer 405 is formed extending in the left-right direction in FIG. The Y electrode layer 407 is formed so as to extend in the direction perpendicular to the paper surface of FIG. As a result, both electrode layers are alternately arranged.

  As is apparent from FIG. 23, the X electrode layer 405 passes from the flat portion 419 of the base sheet 403 through the boundary 421 to the curved portion 417, and further through the opposite boundary 421 to the opposite flat portion 419. It extends to. More specifically, the X electrode layer 405 includes a curved portion corresponding portion 405a and a flat portion corresponding portion 405b. Note that the above description of the X electrode layer 405 also applies to the Y electrode layer 407.

  The conductive ink used to form the X electrode layer 405 and the Y electrode layer 407 is, for example, polyethylene dioxythiophene (PEDOT) or carbon nanotube (CNT).

  The first buffer layer 409A is formed on the entire upper surface of the base sheet 403 and covers the X electrode layer 405. The first buffer layer 409A has a central portion 409a, an outer peripheral portion 409b, and a flat portion 409c. The central portion 409a and the outer peripheral portion 409b correspond to the curved portion 417 of the base sheet 403.

The first buffer layer 409A further includes conductive particles 425.
In this embodiment, the conductive particles 425 are partially disposed in the first buffer layer 409A and the second buffer layer 409B. Specifically, the conductive particles 425 are disposed only in a portion of the first buffer layer 409A corresponding to the outer peripheral portion of the curved portion 417 of the base sheet 403 (the outer peripheral portion 409b of the first buffer layer 409A). This is because this region corresponds to the peripheral portion (the rising portion of the curved surface) in the three-dimensional curved surface where the elongation of the base sheet 403 is maximized.

  The second buffer layer 409 </ b> B is formed on the entire bottom surface of the base sheet 403 and covers the Y electrode layer 307. The first buffer layer 409A has a central portion 409a, an outer peripheral portion 409b, and a flat portion 409c. The central portion 409a and the outer peripheral portion 409b correspond to the curved portion 417 of the base sheet 403. The arrangement of the conductive particles 425 is the same as that of the first buffer layer 409A.

(2) Manufacturing method of touch panel The manufacturing method of the touch panel 1 is demonstrated using FIGS.

  First, as shown in FIG. 24A, the conductive ink to be the X electrode layer 405 is pattern printed on the upper surface of the base sheet 403 in the figure. Next, as shown in FIG. 24B, a silver paste to be used as the routing circuit layer 413 is pattern-printed. Next, as shown in FIG. 24C, the first buffer layer 409 </ b> A is screen-printed on the entire top surface of the base material sheet 403. Next, as shown in FIG. 24 (d), the conductive ink to be the Y electrode layer 407 is pattern printed on the lower surface of the base sheet 403. Next, as shown in FIG. 24E, the second buffer layer 409B is screen-printed on the entire lower surface of the base sheet 403. Such pattern printing is performed by, for example, screen printing or laser processing.

Furthermore, temporary adhesion is performed by thermally laminating an adhesive sheet on the base sheet 403. Thereafter, a release sheet is placed on the adhesive sheet side.
Further, a preform is formed by vacuum / pressure forming. As a result, a preformed base sheet 403 is obtained as shown in FIG.

  Next, the resin flat plate which becomes the transparent cover layer 411 is bonded to the preformed base material sheet 403, and this bonding is performed by heat curing. As a result, the touch panel 401 is completed as shown in FIG. For forming the transparent cover layer 411, injection molding is used in addition to bonding.

8). Sixth Embodiment A touch panel 401 according to a sixth embodiment will be described with reference to FIGS. The description of the same parts as in the above embodiment is omitted.
In this embodiment, the first buffer layer 409 </ b> A is formed corresponding to only the outer peripheral portion of the curved portion 417 and the flat portion 419 of the base sheet 403. That is, the first buffer layer 409A is formed in an annular shape with a predetermined width. Therefore, a space 415 is secured near the center of the curved portion 417 of the base sheet 403.
Further, the second buffer layer 409 </ b> B is formed corresponding to only the outer peripheral portion of the curved portion 417 and the flat portion 419 of the base sheet 403. That is, the second buffer layer 409B is formed in an annular shape with a predetermined width. Accordingly, a space 416 is secured between the base sheet 403 and the transparent cover layer 411 in the vicinity of the center of the curved portion 417 of the base sheet 403.

In this embodiment, the conductive particles 425 are partially disposed in the first buffer layer 409A and the second buffer layer 409B. Specifically, the conductive particles 425 are portions of the first buffer layer 409A and the second buffer layer 409B corresponding to the outer peripheral portion of the curved portion 417 of the base sheet 403 (the first buffer layer 409A and the second buffer layer 409B). The outer peripheral portion 409b) is disposed only. This is because this region corresponds to the peripheral portion (the rising portion of the curved surface) in the three-dimensional curved surface where the elongation of the base sheet 403 is maximized.
27 and 28 correspond to the description of FIG. 24 and FIG. 25 of the above embodiment, and the description thereof will be omitted.

9. Common Items of Embodiments The first to eighth embodiments have the following configurations and functions in common.
(1) A touch panel (for example, touch panel 1, 101, 301, 401) includes a base sheet (for example, base sheet 3, 103, 303, 403) and an electrode layer (for example, a first electrode) made of conductive ink. Layers 5, 105, second electrode layers 7, 107, X electrode layers 305, 405, Y electrode layers 307, 407) and buffer layers (for example, buffer layers 9, 109, 309, first buffer layer 409A, second Buffer layer 409B). A three-dimensional shape is given to the base material sheet. The electrode layer is formed on the base material sheet. The buffer layer is formed on at least a part of the electrode layer, and includes a porous rubber-like member.
In this touch panel, since the buffer layer is formed on the electrode layer, the impact on the electrode layer is reduced in the step of imparting a three-dimensional shape to the base sheet. Therefore, disconnection hardly occurs in the electrode layer.
When only the impact mitigation effect of the buffer layer effect is required, the presence / absence of the conductive particles and the arrangement position are not particularly important.

(2) The buffer layer may include conductive particles (for example, conductive particles 25, 125, 325, 425).
In this touch panel, even when a disconnection occurs in the electrode layer, the conductive state is ensured by the conductive particles.

(3) The buffer layer is formed by bending the base sheet in the step of imparting a three-dimensional shape, and flat portions (19, 119, 319, 419) and curved portions (for example, curved portions 17, 117, 317, 417). ) May be formed at least on the electrode layer from the vicinity of the boundary (for example, the boundary 21, 121, 321, 421) to the edge of the flat portion.
In this touch panel, when the flat part of the base sheet is strongly sandwiched between the molds by injection molding, the shock is alleviated by the buffer layer. Therefore, disconnection hardly occurs in the electrode layer.

10. Other Embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. In particular, a plurality of embodiments and modifications described in this specification can be arbitrarily combined as necessary.
In the embodiment, the three-dimensional curved surface has a hemispherical shape, but may have another shape.

  The present invention can be widely applied to touch panels, in particular, touch panels having a three-dimensional shape.

DESCRIPTION OF SYMBOLS 1 Touch panel 3 Base sheet 5 1st electrode layer 7 2nd electrode layer 7a Curved part corresponding | compatible part 7b Flat part corresponding | compatible part 7c End part 9 Buffer layer 9a Center part 9b Outer peripheral part 9c Flat part 11 Transparent cover layer 13 The routing circuit layer 17 Curved portion 19 Flat portion 21 Boundary 25 Conductive particles

Claims (10)

A base sheet provided with a three-dimensional shape;
An electrode layer made of conductive ink formed on the base sheet;
A buffer layer including a porous rubber-like member formed on the base sheet so as to cover at least a part of the electrode layer;
Touch panel equipped with.   The touch panel according to claim 1, wherein the buffer layer includes conductive particles.   The buffer layer is at least on the electrode layer from the vicinity of the boundary between the flat portion and the curved portion formed by bending the base sheet in the step of imparting the three-dimensional shape to the edge of the flat portion. The touch panel according to claim 1, which is formed. Further comprising conductive particles contained in the buffer layer;
4. The touch panel according to claim 3, wherein the conductive particles are included in a region corresponding to a portion of the curved portion of the base sheet that is close to the flat portion in the buffer layer.   The touch panel according to any one of claims 1 to 4, wherein the porous rubber-like member includes at least a thermoplastic resin or a thermoplastic elastomer and a cross-linkable elastomer as a rubber-like member forming composition. Forming an electrode layer made of conductive ink on a base sheet;
Forming a buffer layer including a porous rubber-like member on the base sheet so as to cover at least a part of the electrode layer;
Providing a three-dimensional shape to the substrate sheet on which the electrode layer and the buffer layer are formed;
A method for manufacturing a touch panel comprising:   The touch panel manufacturing method according to claim 6, wherein the buffer layer includes conductive particles.   The buffer layer is at least on the electrode layer from the vicinity of the boundary between the flat portion and the curved portion formed by bending the base sheet in the step of imparting the three-dimensional shape to the edge of the flat portion. The manufacturing method of the touch panel of Claim 6 formed. Further comprising conductive particles contained in the buffer layer;
The said conductive particle is a manufacturing method of the touch panel of Claim 8 contained in the area | region corresponding to the part which adjoins the said flat part among the said curved parts of the said base material sheet in the said buffer layer.   The said porous rubber-like member is a manufacturing method of the touchscreen in any one of Claims 6-9 containing at least a thermoplastic resin or a thermoplastic elastomer and a crosslinkable elastomer as a composition for rubber-like member formation.

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