JP2007128280A - Conductive sheet for coordinate input device, manufacturing method thereof and coordinate input device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive sheet for a coordinate input device, which is excellent in transparency and coordinate detection accuracy and has low environmental load, and to provide the coordinate input device excellent in coordinate detection accuracy. <P>SOLUTION: The conductive sheet 10a for the coordinate input device is provided with a transparent substrate 11a, a transparent conductive film 12a formed by applying conductive high molecular coating at least to a part of one side of the transparent substrate 11a in one direction, and a pair of band-like electrodes 13a, 13b formed adjacently to a part of the transparent conductive film 12a in a direction orthogonal to the application direction of the conductive high molecular coating. In the coordinate input device provided with a pair of conductive sheets for the coordinate input device, respective transparent conductive films are opposed to each other through a spacing and a rectangular input area whose sides are formed by respective band-like electrodes of the conductive sheets is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a conductive sheet for a coordinate input device provided in the coordinate input device and a method for manufacturing the same. The present invention also relates to a coordinate input device provided in a touch panel or the like.

In an input device such as a touch panel, a coordinate input device that detects coordinates of a contact point where a finger, a stylus, or the like touches is provided on an image display device. As a coordinate input device, a conductive sheet comprising a transparent substrate, a transparent conductive film formed on one side of the transparent substrate, and a pair of strip-like electrodes adjacent to a part of the transparent conductive film and parallel to each other One having a pair is known. In this coordinate input device, a pair of conductive sheets for coordinate input devices face each other while the transparent conductive films are spaced from each other, and each strip electrode of the conductive sheet for coordinate input devices is a side. A rectangular input area is formed (see, for example, Patent Document 1).
For example, a carbon paste film or an ITO vapor deposition film is used as the transparent conductive film of the conductive sheet for the coordinate input device. Moreover, as a material of the strip electrode, for example, a silver paste or the like is used.
Japanese Patent Laid-Open No. 10-63428

However, when a carbon paste film is used as the transparent conductive film of the conductive sheet for the coordinate input device provided in the coordinate input device, the transparency of the input area is insufficient, and thus the image visibility of the image display device is low. It became low.
Moreover, since ITO has a problem of high environmental load, a transparent conductive film that does not use an ITO vapor-deposited film has been demanded. In addition, when an ITO vapor-deposited film is used as the transparent conductive film, the ITO vapor-deposited film in the non-input area may be removed by etching or the like in order to provide wiring from the strip electrode. The number of manufacturing steps sometimes increased.
Therefore, in recent years, it has been studied to form a transparent conductive film by applying a coating containing a π-conjugated conductive polymer on a transparent substrate.

However, when a conductive sheet having a transparent conductive film formed by applying a conductive polymer paint containing a π-conjugated conductive polymer on a transparent substrate is applied to a coordinate input device, coordinate detection is performed. The accuracy may be reduced.
This invention is made | formed in view of the said situation, and it aims at providing the electroconductive sheet for coordinate input devices which is excellent in transparency and coordinate detection accuracy, and has little environmental impact, and its manufacturing method. Moreover, it aims at providing the coordinate input device excellent in coordinate detection accuracy.

  The present inventors have investigated the cause of low coordinate detection accuracy when a conductive sheet provided with a transparent conductive film formed by applying a conductive polymer paint is used in a coordinate input device. It has been found that the cause is coating spots and scratches formed on the film in parallel with the strip electrode. In addition, when the conductive polymer paint is low in transparency, such as carbon paste, coating spots and scratches can be confirmed visually or by an optical method such as image processing. However, the paint contains a π-conjugated conductive polymer. In this case, since the transparency is high, it was found that confirmation by visual observation or image processing is difficult. Based on these findings, the inventors have invented the following conductive sheet for a coordinate input device, a manufacturing method thereof, and a coordinate input device.

The conductive sheet for coordinate input device of the present invention includes a transparent base material, a transparent conductive film formed by applying a conductive polymer paint in one direction on at least a part of one side of the transparent base material, and the transparent conductive material. It is characterized by comprising a pair of strip electrodes provided adjacent to a part of the film and perpendicular to the direction of application of the conductive polymer paint.
The method for producing a conductive sheet for a coordinate input device according to the present invention includes a transparent conductive film forming step of forming a transparent conductive film by applying a conductive polymer paint in one direction on at least a part of one side of a transparent substrate,
And an electrode installation step of providing a pair of strip electrodes in a direction orthogonal to the direction of application of the conductive polymer paint on a part of the transparent conductive film.
The coordinate input device of the present invention is a coordinate input device comprising a pair of the above-described conductive sheets for coordinate input devices,
The pair of conductive sheets for the coordinate input device are facing each other while the transparent conductive films are spaced apart from each other,
A rectangular input region is formed with each band-like electrode of the conductive sheet for coordinate input device as a side.

The conductive sheet for a coordinate input device of the present invention is excellent in transparency and coordinate detection accuracy and has a low environmental load.
According to the method for manufacturing a conductive sheet for a coordinate input device of the present invention, it is possible to manufacture a conductive sheet for a coordinate input device that is excellent in transparency and coordinate detection accuracy and has a small environmental load.
The coordinate input device of the present invention is excellent in coordinate detection accuracy.

(Conductive sheet for coordinate input device)
An embodiment of a conductive sheet for coordinate input device (hereinafter abbreviated as a conductive sheet) of the present invention will be described.
1 and 2 show a conductive sheet according to this embodiment. The conductive sheet 10a includes a rectangular transparent substrate 11a, a transparent conductive film 12a formed in a rectangular shape on a part of one surface of the transparent substrate 11a, and the transparent conductive film 12a opposite to the transparent substrate 11a side. A pair of strip electrodes 13a and 13b adjacent to a part of the surface.

It does not restrict | limit especially as the transparent base material 11a, A glass substrate may be sufficient and a transparent resin film may be sufficient.
Examples of the resin constituting the transparent resin film include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, polyvinyl chloride, polycarbonate, polyvinylidene fluoride, and the like. Polyethylene terephthalate is more preferable from the viewpoint of excellent resistance. The transparent resin film may be subjected to a primer treatment. However, it is preferable to use a flexible transparent resin film for the conductive sheet (for example, the conductive sheet 10b in FIG. 9) disposed on the side (surface side) touched by a finger, stylus, etc., and its thickness. Is preferably 50 to 300 μm. Furthermore, for the conductive sheet (for example, the conductive sheet 10a in FIG. 9) disposed on the side opposite to the side touched by a finger, stylus, etc., a material that is not easily bent such as a glass substrate is selected from the viewpoint of input accuracy. The thickness is preferably 0.5 to 2 mm.

The transparent conductive film 12a in the present embodiment, the one surface of the transparent substrate 11a, a conductive polymer coating material is a film which is formed by applying in the direction L ₁ along the long side of the transparent substrate 11a.
Moreover, the transparent conductive film 12a in the present embodiment is formed in a portion other than the long side end portion 11c of the transparent substrate 11a.
The thickness of the transparent conductive film 12a is preferably 0.01 to 10 [mu] m, more preferably 0.05 to 5 [mu] m, and most preferably 0.1 to 2 in terms of transparency, conductivity and durability. The range is 0.0 μm.

The conductive polymer paint that forms the transparent conductive film 12a contains at least a π-conjugated conductive polymer and a solvent.
The π-conjugated conductive polymer can be used as long as the main chain is an organic polymer having a π-conjugated system. Examples thereof include polypyrroles, polythiophenes, polyacetylenes, polyphenylenes, polyphenylene vinylenes, polyanilines, polyacenes, polythiophene vinylenes, and copolymers thereof. From the viewpoint of stability in air, polypyrroles, polythiophenes and polyanilines are preferred.
Even if the π-conjugated conductive polymer remains unsubstituted, sufficient conductivity can be obtained. However, in order to further increase the conductivity, an alkyl group, a carboxyl group, a sulfo group, an alkoxyl group, a hydroxyl group, etc. It is preferable to introduce a functional group into the π-conjugated conductive polymer.

  Specific examples of the π-conjugated conductive polymer include polypyrrole, poly (N-methylpyrrole), poly (3-methylpyrrole), poly (3-ethylpyrrole), poly (3-n-propylpyrrole), poly (3-butylpyrrole), poly (3-octylpyrrole), poly (3-decylpyrrole), poly (3-dodecylpyrrole), poly (3,4-dimethylpyrrole), poly (3,4-dibutylpyrrole) , Poly (3-carboxypyrrole), poly (3-methyl-4-carboxypyrrole), poly (3-methyl-4-carboxyethylpyrrole), poly (3-methyl-4-carboxybutylpyrrole), poly (3 -Hydroxypyrrole), poly (3-methoxypyrrole), poly (3-ethoxypyrrole), poly (3-butoxypyrrole), poly (3-hexyl) Ruoxypyrrole), poly (3-methyl-4-hexyloxypyrrole), poly (3-methyl-4-hexyloxypyrrole), poly (thiophene), poly (3-methylthiophene), poly (3-ethylthiophene) ), Poly (3-propylthiophene), poly (3-butylthiophene), poly (3-hexylthiophene), poly (3-heptylthiophene), poly (3-octylthiophene), poly (3-decylthiophene), Poly (3-dodecylthiophene), poly (3-octadecylthiophene), poly (3-bromothiophene), poly (3-chlorothiophene), poly (3-iodothiophene), poly (3-cyanothiophene), poly ( 3-phenylthiophene), poly (3,4-dimethylthiophene), poly (3,4-dibutylthio) Phen), poly (3-hydroxythiophene), poly (3-methoxythiophene), poly (3-ethoxythiophene), poly (3-butoxythiophene), poly (3-hexyloxythiophene), poly (3-heptyloxy) Thiophene), poly (3-octyloxythiophene), poly (3-decyloxythiophene), poly (3-dodecyloxythiophene), poly (3-octadecyloxythiophene), poly (3,4-dihydroxythiophene), poly (3,4-dimethoxythiophene), poly (3,4-diethoxythiophene), poly (3,4-dipropoxythiophene), poly (3,4-dibutoxythiophene), poly (3,4-dihexyloxy) Thiophene), poly (3,4-diheptyloxythiophene), poly (3,4- Octyloxythiophene), poly (3,4-didecyloxythiophene), poly (3,4-didodecyloxythiophene), poly (3,4-ethylenedioxythiophene), poly (3,4-propylenedioxy) Thiophene), poly (3,4-butenedioxythiophene), poly (3-methyl-4-methoxythiophene), poly (3-methyl-4-ethoxythiophene), poly (3-carboxythiophene), poly (3 -Methyl-4-carboxythiophene), poly (3-methyl-4-carboxyethylthiophene), poly (3-methyl-4-carboxybutylthiophene), polyaniline, poly (2-methylaniline), poly (3-isobutyl Aniline), poly (2-aniline sulfonic acid), poly (3-aniline sulfonic acid) and the like. That.

(solvent)
Examples of the solvent contained in the conductive polymer paint include water, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylene phosphortriamide, acetonitrile, benzoate. Polar solvents such as nitrile, phenols such as cresol, phenol and xylenol, alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone and methyl ethyl ketone, hydrocarbons such as hexane, benzene and toluene, formic acid and acetic acid Carboxylic acids such as ethylene carbonate and propylene carbonate, ether compounds such as dioxane and diethyl ether, ethylene glycol dialkyl ether, propylene glycol dialkyl ether, Chain ethers such as reethylene glycol dialkyl ether and polypropylene glycol dialkyl ether, heterocyclic compounds such as 3-methyl-2-oxazolidinone, nitrile compounds such as acetonitrile, glutaronitrile, methoxyacetonitrile, propionitrile, benzonitrile, etc. Can be mentioned. These solvents may be used alone, as a mixture of two or more kinds, or as a mixture with other organic solvents.

The conductive polymer coating preferably contains a solubilized polymer for solubilizing the π-conjugated conductive polymer in a solvent. Examples of the solubilized polymer include a polymer having an anion group (polyanion) and a polymer having an electron withdrawing group.
Specific examples of the polymer having an anion group include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly (2-acrylamido-2-methylpropane sulfonic acid), poly Isoprene sulfonic acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl carboxylic acid, polymethacryl carboxylic acid, poly (2-acrylamido-2-methylpropane carboxylic acid), polyisoprene carboxylic acid, polyacrylic acid, etc. Is mentioned.
Specific examples of the polymer having an electron withdrawing group include polyacrylonitrile, polymethacrylonitrile, acrylonitrile-styrene resin, acrylonitrile-butadiene resin, acrylonitrile-butadiene-styrene resin, and a resin obtained by cyanoethylating a hydroxyl group or amino group-containing resin. (For example, cyanoethyl cellulose), polyvinyl pyrrolidone, alkylated polyvinyl pyrrolidone, nitrocellulose and the like.

  The total light transmittance of the transparent conductive film 12a is preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more. If the total light transmittance of the transparent conductive film 12a is within the above range, the touch panel provided with the conductive sheet 10a is particularly excellent in image visibility because it has sufficiently high transparency.

The strip electrodes 13a and 13b are provided in a direction orthogonal to the application direction of the conductive polymer paint (direction L ₁ along the long side). Specifically, the strip electrodes 13a, 13b in this embodiment in the vicinity of the short sides of the rectangular transparent substrate 11a, is provided by screen printing or the like in the direction L ₂ along the short sides.
Examples of the material of the strip electrodes 13a and 13b include conductive pastes such as silver paste, carbon paste, and copper paste.
Since the wiring resistance of the strip electrodes 13a and 13b (resistance between the points 600a and 600b) affects the coordinate detection accuracy, the resistance between the strip electrodes 13a and 1b is sufficiently smaller than, for example, 1% or less, preferably 0.1%. It is more preferable that
The dimensions of the strip electrodes 13a and 13b are appropriately selected according to the size of the input area of the coordinate input device, but the length is usually set to be equal to or greater than the length of the input area, and L _{2 of the} transparent conductive film 12a. It is preferably equal to the length in the direction and longer than the distance between the strip electrodes 13c and 13d. In addition, the width needs to be large enough to achieve the above resistance, but it is preferable that the width is as narrow as possible in order to secure the input area. Usually, the relationship between the printing workability of the conductive paste and the external dimensions of the coordinate input device From about 0.5 to 15 mm.

(Method for producing conductive sheet)
A method for manufacturing the conductive sheet 10a will be described.
In the method for producing a conductive sheet of the present embodiment example, first, in the transparent conductive film forming step, along the long side of the transparent base material 11a, in a portion other than the long side end portion 11c on one side of the transparent base material 11a. by applying a conductive polymer coating material in the direction L ₁ to form a rectangular transparent conductive film 12a.
The method for applying the conductive polymer coating is not particularly limited, and a bar coater such as a wire coater, a roll coater, or the like can be used. Among these, a roll coater is preferable because it can be continuously applied and is excellent in productivity. However, in the case of small-scale production, a bar coater is preferable because the thickness can be easily controlled accurately.

Next, in the electrode installation step, in the vicinity of the short side of the surface of the transparent conductive film 12a opposite to the transparent substrate 11a side, the conductive polymer coating application direction (direction L ₁ along the long side). Thus, a pair of strip electrodes 13a and 13b are provided in the orthogonal direction (direction L ₂ along the short side). As a method of providing the strip electrodes 13a and 13b in a direction orthogonal to the application direction of the conductive polymer paint, for example, a method of applying the conductive paste in a direction orthogonal to the application direction of the conductive polymer paint, etc. Can be mentioned. Here, examples of the conductive paste include silver paste, carbon paste, and copper paste.

In the conductive sheet 10a described above, a pair of strip electrodes 13a and 13b are provided in a direction orthogonal to the direction of application of the conductive polymer paint (direction L ₁ along the long side) (direction L ₂ along the short side). Therefore, even when application spots or scratches are formed on the transparent conductive film 12a in parallel with the strip electrodes 13a and 13b, the uniformity of the transparent conductive film 12a between the strip electrodes 13a and 13b can be ensured. Therefore, it is difficult to cause a defect in coordinate detection due to coating spots or scratches, and the coordinate detection accuracy of the coordinate input device can be increased.
Moreover, since the transparent conductive film 12a is formed from a conductive polymer paint, it has excellent transparency and a low environmental load.

The conductive sheet of the present invention is not limited to the above-described embodiment example. For example, the conductive sheet, such as shown in FIG. 3, the conductive polymer coating material transparent conductive film 12b is applied in the direction L ₂ along the short side of the transparent substrate 11b is formed, the strip electrodes 13c, 13d are it may be those provided in the direction L ₁ along the long side of the transparent substrate 11b.

Further, in the above-described embodiment, the conductive polymer coating is applied to the portion other than the long side end portion 11c of the transparent substrate 11a to form the transparent conductive film, but the short side of the transparent substrate 11a. A transparent conductive film may be formed by applying a conductive polymer paint to portions other than the side end portions.
Alternatively, the transparent conductive film 12a may be formed by applying a conductive polymer paint on one side of the transparent substrate 11a. However, when the wiring is formed on the transparent substrate 11a, a part of the transparent conductive film 12a is removed by sand blasting, etching, or dedoping by applying an alkaline component such as aqueous ammonia.
In the above-described embodiment, the transparent base material 11a and the transparent conductive film 12a are rectangular. However, the transparent substrate 11a and the transparent conductive film 12a are not necessarily rectangular, and may be circular, elliptical, or polygonal other than rectangular. .

(Coordinate input device)
An embodiment of the coordinate input device of the present invention will be described.
4 and 5 show a coordinate input device according to this embodiment. The coordinate input device 1 includes a conductive sheet 10a shown in FIG. 1 (hereinafter referred to as a first conductive sheet 10a) and a conductive sheet 10b shown in FIG. 3 (hereinafter referred to as a second conductive sheet 10b). And the second conductive sheet 10b is arranged on the surface side.
Further, in the coordinate input device 1 of the present embodiment example, the first conductive sheet 10a and the second conductive sheet 10b are spaced apart from each other by the transparent conductive films 12a and 12b via the insulating spacer 20. Face to face. Further, in the coordinate input device 1 of the present embodiment, a rectangular input region 30 is formed with the strip electrodes 13a to 13d of the first conductive sheet 10a and the second conductive sheet 10b as sides.
In this embodiment, the direction along the long sides of the transparent base materials 11a and 11b is the X direction, and the direction along the short sides of the transparent base materials 11a and 11b is the Y direction.

  The coordinate input device 1 also applies voltage to the first voltage application circuit 40a for applying a voltage to the strip electrodes 13a and 13b of the first conductive sheet 10a and to the strip electrodes 13c and 13d of the second conductive sheet 10b. A second voltage application circuit 40b for applying voltage, a first voltage measuring device 50a connected to the first voltage application circuit 40a, and a second voltage measurement connected to the second voltage application circuit 40b The first electrode 60b, the first wiring 60a connecting the strip electrodes 13a, 13b of the first conductive sheet 10a and the first voltage application circuit 40a, the strip electrodes 13c, 13d of the second conductive sheet 10b, and the second The second wiring 60b is connected to the voltage application circuit 40b.

  There is no restriction | limiting in particular as the insulation spacer 20 in the coordinate input device 1, Although it can select suitably from a well-known thing, the thing made from an acrylic resin is preferable at the point of transparency.

The first voltage application circuit 40a has a power supply 41a and a switch means 42a, and applies a constant voltage to the first conductive sheet 10a via the first wiring 60a when in the H state. It is.
The second voltage application circuit 40b has a power source 41b and a switch means 42b, and applies a constant voltage to the second conductive sheet 10b via the second wiring 60b when in the H state. It is. Further, the second voltage application circuit 40b includes a pull-up resistor 43 for holding the second conductive sheet 10b at a constant voltage when not pressed and a second conductive sheet 10b that is cut off from the pull-up resistor 43. Are provided with a blocking means 44.
As the switch means 42a and 42b in the first voltage application circuit 40a and the second voltage application circuit 40b, a diode, a transistor, a three-state buffer, an analog switch, or the like can be used.

As the first voltage measuring device 50a and the second voltage measuring device 50b, for example, an A / D converter, a comparator, or the like can be used.
The first wiring 60a is formed by direct patterning on the transparent base material 11a (see FIGS. 6 and 7), and the second wiring 60b is formed by direct patterning on the transparent base material 11b. (See FIG. 8). The 1st wiring 60a and the 2nd wiring 60b are formed from a conductive paste etc. like the strip electrodes 13a-13d.

In the coordinate input device 1, the second conductive sheet 10b is pressed against the stylus 70 or the like, and when the second conductive sheet 10b is pressed, the pressed portion contacts the first conductive sheet 10a. (See FIG. 9). In the present embodiment, the point where the first conductive sheet 10a and the second conductive sheet 10b are in contact is referred to as a contact point S.
Further, when it is no longer pressed, the shape of the second conductive sheet 10b is restored, and the first conductive sheet 10a and the second conductive sheet 10b are spaced again.

  An example of coordinate detection by the coordinate input device 1 will be described. In the following example, a constant voltage is applied between the strip electrodes 13a and 13b of the first conductive sheet 10a or between the strip electrodes 13c and 13d of the second conductive sheet 10b, and then from the strip electrodes 13a or 13c. This is an example in which a constant voltage method for obtaining coordinates by measuring a voltage up to a contact point S is applied.

In this example, the second conductive sheet 10b is pressed at a contact point S with a finger or a stylus, and the transparent conductive film 12a of the first conductive sheet 10a and the transparent conductive film 12b of the second conductive sheet 10b are electrically connected. It is the coordinate detection of the contact point S at the time of doing.
In this coordinate detection, when the transparent conductive film 12a of the first conductive sheet 10a and the transparent conductive film 12b of the second conductive sheet 10b are conducted, the first voltage application circuit 40a is in the H state (the switch means 42a is turned on). ), A voltage is applied between the strip electrodes 13a and 13b of the first conductive sheet 10a to form a potential gradient in the X direction between the strip electrodes 13a and 13b. Further, the second voltage application circuit 40b is set to the L state (the switch means 42b is turned OFF) (that is, no voltage is applied between the strip electrodes 13c and 13d of the second conductive sheet 10b).
In this state, the potential from one strip electrode 13a to the contact point S in the first conductive sheet 10a is passed through the transparent conductive film 12b in contact with the transparent conductive film 12a at the contact point S and the second wiring 60b. The second voltage measuring device 50b is used for the measurement. Then, the coordinate in the X direction is obtained by obtaining the distance from the strip electrode 13a to the contact point S based on a voltage-distance calibration curve prepared in advance.
Thereafter, the second voltage application circuit 40b is set to the H state (switch means 42b is turned on), and a voltage is applied between the strip electrodes 13c and 13d of the second conductive sheet 10b to form a potential gradient in the Y direction. The first voltage application circuit 40a is set to the L state (that is, no voltage is applied between the strip electrodes 13a and 13b of the first conductive sheet 10a). In this state, the potential from one band-like electrode 13c to the contact point S in the second conductive sheet 10b is passed through the transparent conductive film 12a that contacts the transparent conductive film 12b at the contact point S and the first wiring 60a. Then, measurement is performed by the first voltage measuring device 50a. Then, the coordinate in the Y direction is obtained by obtaining the distance from the strip electrode 13c to the contact point S based on a voltage-distance calibration curve prepared in advance.
In this way, the coordinates in the X direction and the coordinates in the Y direction can be obtained.

For the coordinate detection, a method other than the constant voltage method can be applied. For example, a constant current is passed from one conductive sheet to the other conductive sheet, and a resistance value from one strip electrode to the contact point is obtained from a potential difference between the strip electrodes in one conductive sheet, and prepared in advance. A constant current method for obtaining coordinates based on a resistance value-distance calibration curve can be applied.
However, the constant voltage method is preferable because measurement is possible even if application spots or scratches are formed in the vicinity of the strip electrode.

  In the coordinate input device 1 described above, the transparent conductive films 12a and 12b formed by applying the conductive polymer paint on one side of the transparent base materials 11a and 11b in one direction, and the application direction of the conductive polymer paint. Since the first conductive sheet 10a and the second conductive sheet 10b having a pair of strip electrodes 13a to 13d provided in the orthogonal direction are provided, coating spots and scratches are formed on the transparent conductive films 12a and 12b. Even if it is applied, the influence is small and the coordinate detection accuracy is excellent.

  Further, as in the present embodiment, if the first wiring 60a and the second wiring 60b are formed by direct patterning on the transparent base materials 11a and 11b, the transparent conductive films 12a, It is not necessary to provide an insulating part on 12b. As a result, it is possible to prevent the transparent conductive films 12a and 12b from being affected by the dissolution of the transparent conductive films 12a and 12b due to the solvent of the resist ink and the change in the temperature and humidity, and the coordinate detection accuracy is further improved.

Note that the coordinate input device of the present invention is not limited to the above-described embodiment. In the above-described embodiment, the first wiring 60a and the second wiring 60b are formed by being directly patterned on the transparent base materials 11a and 11b. For example, as shown in FIG. The insulating part 61 may be formed on the transparent conductive film 12a by printing a resist pattern or applying an adhesive tape, and may be formed on the insulating part 61.
In the coordinate input device 1, the second conductive sheet 10 b is disposed on the front side, but the first conductive sheet 10 a may be disposed on the front side.

Examples of the present invention will be specifically described below, but the present invention is not limited to the examples.
(Production Example 1) Synthesis of polystyrene sulfonic acid 206 g of sodium styrene sulfonate was dissolved in 1000 ml of ion-exchanged water, and 1.14 g of ammonium persulfate oxidizing agent solution previously dissolved in 10 ml of water was stirred at 80 ° C. The solution was added dropwise for 20 minutes, and the solution was stirred for 2 hours.
1000 ml and 10,000 ml of ion-exchanged water were added to the sodium styrenesulfonate-containing solution thus obtained to 10% by weight, and about 10,000 ml of the polystyrenesulfonic acid-containing solution was removed using an ultrafiltration method. Then, 10,000 ml of ion-exchanged water was added to the remaining liquid, and about 10,000 ml of solution was removed using an ultrafiltration method. The above ultrafiltration operation was repeated three times.
Furthermore, about 10,000 ml of ion-exchanged water was added to the obtained filtrate, and about 10,000 ml of solution was removed using an ultrafiltration method. This ultrafiltration operation was repeated three times.
The ultrafiltration conditions were as follows (the same applies to other examples).
Molecular weight cut off of ultrafiltration membrane: 30K
Cross flow type Supply liquid flow rate: 3000 ml / min Membrane partial pressure: 0.12 Pa
Water in the obtained solution was removed under reduced pressure to obtain colorless solid polystyrene sulfonic acid.

Production Example 2 Synthesis of Ester Compound 43.6 g of pyromellitic acid dianhydride and 73.6 g of glycerin were placed in an eggplant-shaped flask and mixed. Put eggplant-shaped flask containing pyromellitic acid dianhydride and glycerin mixture in oil bath oil bath at 100 ° C and stir for 10 minutes, then add 0.1 g of p-toluenesulfonic acid. Stir for 1 hour. Thereby, pyromellitic acid dianhydride and glycerin were dehydrated to obtain a reaction solution containing an ester compound.
Then, 115 g of ion exchange water was added to the obtained reaction solution, dissolved while stirring, and ion exchange water was further added so that the solid concentration of the solution was 50% by mass to adjust the concentration. The aqueous solution thus obtained was used as an ester compound aqueous solution.

(Production Example 3) Synthesis of conductive polymer paint 14.2 g of 3,4-ethylenedioxythiophene and a solution obtained by dissolving 36.7 g of polystyrene sulfonic acid obtained in Production Example 1 in 2000 ml of ion-exchanged water, Were mixed at 20 ° C.
While maintaining the mixed solution thus obtained at 20 ° C. and stirring, 29.64 g of ammonium persulfate dissolved in 200 ml of ion exchange water and 8.0 g of ferric sulfate oxidation catalyst solution were slowly added, The reaction was stirred for 3 hours.
2000 ml of ion-exchanged water was added to the resulting reaction solution, and about 2000 ml of solution was removed using an ultrafiltration method. This operation was repeated three times.
Then, 200 ml of sulfuric acid diluted to 10% by mass and 2000 ml of ion-exchanged water are added to the treatment liquid that has been subjected to the filtration treatment, and about 2000 ml of the treatment liquid is removed using an ultrafiltration method. Ion exchange water was added and about 2000 ml of liquid was removed using ultrafiltration. This operation was repeated three times.
Furthermore, 2000 ml of ion-exchanged water was added to the obtained treatment liquid, and about 2000 ml of the treatment liquid was removed using an ultrafiltration method. This operation was repeated 5 times to obtain about 1.5% by mass of blue polystyrenesulfonic acid-doped poly (3,4-ethylenedioxythiophene) (PSS-PEDOT). This was designated as a π-conjugated conductive polymer solution.
Then, to 100 ml of the obtained π-conjugated conductive polymer solution, 3.0 g of the ester compound aqueous solution obtained in Production Example 2 was added and dispersed uniformly to obtain a conductive polymer paint.

(Example)
1 and 3 and the coordinate input device 1 of FIG. 4 were produced as follows.
The conductive polymer paint obtained in Production Example 3 was subjected to a primer treatment on the first side of the rectangular first polyethylene terephthalate film (T-680EW07, made of Mitsubishi polyester film, transparent substrate 11a) on one side of the long side. a portion other than 11c, is applied in the direction L ₁ along the long side with a wire coater to form a rectangular transparent conductive film 12a is dry. Then, on the transparent conductive film 12a, to obtain strip-shaped electrode 13a and a silver paste was applied in a direction L ₂ along the short side, a first conductive sheet 10a is provided 13b. Further, the first wiring 60a was provided by applying a silver paste to the remaining part of one side of the first polyethylene terephthalate film.
Further, a portion other than short end of the one side of the second polyethylene terephthalate film of the first polyethylene terephthalate film having the same shape (transparent substrate 11b), in the direction L ₂ along the short side by a wire coater, The first conductive sheet 10a was applied to the same area as the transparent conductive film 12a and dried to form a rectangular transparent conductive film 12b. Then, on the transparent conductive film 12b, the strip electrodes 13c silver paste was applied in a direction L ₁ along the long sides, provided with a 13d to give the second conductive sheet 10b. A second wiring 60b was provided by applying a silver paste to the remaining part of one side of the second polyethylene terephthalate film.

  Next, the first conductive sheet 10a and the second conductive sheet 10b face each other with the gap between the transparent conductive films 12a and 12b via the insulating spacer 20, and the first conductive sheet 10a and It arrange | positioned so that the rectangular-shaped input area 30 which used the strip | belt-shaped electrodes 13a-13d in the 2nd conductive sheet 10b as a side might be formed. The first voltage applying circuit 40a and the first voltage measuring device 50a are connected to the first wiring 60a, and the second voltage applying circuit 40b and the second voltage measuring device 50b are connected to the second wiring 60b. Thus, the coordinate input device 1 was obtained.

The second conductive sheet 10b is pressed against the first conductive sheet 10a on the strip electrode 13a side in the input area 30 of the coordinate input device 1, and then the contact point from the strip electrode 13a side to the strip electrode 13b side. S was moved continuously. At this time, the voltage from the strip electrode 13a to the contact point S was measured by the second voltage measuring device 50b connected to the second conductive sheet 10b. The result is shown in FIG.
As shown in FIG. 11, in the coordinate input device 1 of this example, since the relationship between the distance from the strip electrode 13a to the contact point S and the voltage is proportional, the coordinate detection accuracy is excellent.

(Comparative example)
The coordinate input device is the same as in Example 1 except that when the first conductive sheet is obtained, a conductive polymer paint is applied to the first polyethylene terephthalate film in the direction along the short side of the transparent substrate. Got. And like Example 1, when the voltage from a strip | belt-shaped electrode to a contact point was measured, there existed a location where a voltage rose rapidly (refer FIG. 12). This seems to be because the coating spots were formed in the direction along the short side of the transparent substrate.
In such a coordinate input device, since there is a discontinuous portion in the relationship between the distance from the strip electrode to the contact point and the voltage, the coordinate detection accuracy is lowered.

It is a top view which shows one Example of the electrically conductive sheet of this invention. It is A-A 'sectional drawing of FIG. It is a top view which shows other embodiment examples of the electrically conductive sheet of this invention. It is a top view which shows one example of embodiment of the coordinate input device of this invention. FIG. 5 is a B-B ′ cross-sectional view of FIG. 4. It is a top view which shows the 1st conductive sheet and 1st wiring with which the coordinate input device of FIG. 4 is equipped. It is C-C 'sectional drawing of FIG. It is a top view which shows the 2nd conductive sheet and 2nd wiring with which the coordinate input device of FIG. 4 is equipped. FIG. 5 is a cross-sectional view illustrating a state when the first conductive sheet and the second conductive sheet are in contact with each other in the coordinate input device of FIG. 4. It is sectional drawing which shows the other example of the wiring connected to a conductive sheet. It is a graph which shows the relationship between the distance from the strip | belt-shaped electrode to a contact point, and a voltage in the coordinate input device of an Example. It is a graph which shows the relationship between the distance from the strip | belt-shaped electrode in a coordinate input device of a comparative example to a contact point, and a voltage.

Explanation of symbols

1 Coordinate Input Device 10a Conductive Sheet (First Conductive Sheet)
10b Conductive sheet (second conductive sheet)
11a, 11b Transparent base material 12a, 12b Transparent conductive film 13a, 13b, 13c, 13d Strip electrode 20 Insulating spacer 30 Input region 40a First voltage application circuit 40b Second voltage application circuit 41a, 41b Power supply 42a, 42b Switch means 43 Pull-up resistor 44 Blocking means 50a First voltage measuring device 50b Second voltage measuring device 60a First wiring 60b Second wiring 60c Wiring 61 Insulating part 70 Stylus S Contact point

Claims (3)

  A transparent base material, a transparent conductive film formed by applying a conductive polymer paint in one direction on at least a part of one side of the transparent base material, a part of the transparent conductive film, A conductive sheet for a coordinate input device, comprising: a pair of strip electrodes provided in a direction orthogonal to the direction of application of the molecular paint. A transparent conductive film forming step of forming a transparent conductive film by applying a conductive polymer paint in one direction on at least a part of one side of the transparent substrate;
A method for producing a conductive sheet for a coordinate input device, comprising: an electrode installation step in which a pair of strip electrodes are provided in a direction orthogonal to a direction in which a conductive polymer paint is applied on a part of a transparent conductive film. A coordinate input device comprising a pair of conductive sheets for the coordinate input device according to claim 1,
The pair of conductive sheets for the coordinate input device are facing each other while the transparent conductive films are spaced apart from each other,
A coordinate input device, characterized in that a rectangular input region having a side of each strip electrode of the conductive sheet for coordinate input device is formed.

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