Patent Application
20140000944
1. Technical Field
The present invention relates to a touch panel mainly used for operating various kinds of electronic devices.
2. Background Art
Recently, as various kinds of electronic devices such as a cellular phone or a digital still camera have become highly functional and more diversified, an increasing number of electronic devices are mounting light transmissive touch panels on front surfaces of display elements such as a liquid crystal display element. Users can switch various functions of the electronic device by touching and operating the touch panel with a finger or the like while seeing a display of the display element provided on a back surface through the touch panel. The touch panel used as described above is required to be easy to recognize the display element on the back surface, low in cost, and capable of performing reliable operations.
A conventional touch panel will be described with reference to
In
Reference numeral 4 represents a film-shaped light transmissive lower substrate which is similar to upper substrate 1. A plurality of lower conductive layers 5 and a plurality of lower electrodes 6 are formed on an upper surface of lower substrate 4. Lower conductive layer 5 is made of light transmissive material such as indium tin oxide, and formed so as to extend in a roughly band-shaped form in the horizontal direction perpendicular to upper conductive layer 2. Lower electrode 6 is made of material such as silver or carbon, and provided in such a manner that one end of lower electrode 6 is connected to an end part of lower conductive layer 5, and the other end of lower electrode 6 is positioned at a peripheral right end of lower substrate 4. Lower electrode 6 is formed so as to extend in the horizontal direction parallel to lower conductive layer 5.
Reference numeral 7 represents a plate-shaped or film-shaped light transmissive cover substrate. The touch panel is configured in such a manner that upper substrate 1 is overlapped on the upper surface of lower substrate 4, cover substrate 7 is overlapped on the upper surface of upper substrate 1, and these are bonded respectively with a bonding agent (not shown) or the like.
The touch panel thus configured is disposed on a front surface of a display element such as a liquid crystal display element and mounted on the electronic device. Upper electrodes 3 and lower electrodes 6 provided so as to extend at the peripheral right ends of the touch panel are electrically connected to an electronic circuit (not shown) of the electronic device, through a flexible wiring board, a connector (not shown), or the like.
In the above configuration, while a voltage is sequentially applied to upper electrodes 3 and lower electrodes 6 from the electronic circuit, an upper surface of cover substrate 7 is touched and operated with a finger or the like, according to a display of the display element provided on a back surface of the touch panel. Thus, electrostatic capacity between upper conductive layer 2 and lower conductive layer 5 positioned at the operated part is changed, and the electronic circuit detects the operated position, so that various functions of the electronic device can be switched.
For example, under a condition that a plurality of menus are displayed on the display element on the back surface, the upper surface of cover substrate 7 positioned above a desired menu is touched with a finger or the like. Electric charge is partially conducted to this finger, and the capacity between upper conductive layer 2 and lower conductive layer 5 is changed at the operated part of the touch panel. When the electronic circuit detects the change in capacity, the desired menu can be selected.
As conventional art document information related to the present invention of this application, Unexamined Japanese Patent Publication No. 2009-93397 is known, for example.
However, according to the conventional touch panel, upper substrate 1 having upper conductive layers 2 formed on the upper surface and lower substrate 4 having lower conductive layers 5 formed on the upper surface are overlapped and attached on a lower surface of cover substrate 7. Therefore, the touch panel is large in thickness as a whole, and has many components, and its cost is high.
The present application provides a touch panel which is reduced in number of components, low in cost, and capable of performing reliable operations.
A touch panel according to the present invention includes a light transmissive substrate, a first light transmissive conductive layer, and a second light transmissive conductive layer. The first conductive layer is provided on an upper surface of the substrate, and extending in a roughly band-shaped form in a first direction. The second conductive layer is provided on the upper surface of the substrate, insulated from the first conductive layer, and extending in a roughly band-shaped form in a second direction perpendicular to the first direction. The first conductive layers and the second conductive layers are plurally provided. The second conductive layer includes a plurality of conductive parts provided on the upper surface of the substrate, and a connecting part provided for connecting the conductive parts in the second direction, and provided above the first conductive layer, and material of the connecting part is resin containing dispersed conductive fine wires.
Since the first conductive layers and the second conductive layers are provided on the upper surface of the one substrate, the number of components is small, and assembling can be easily performed. In addition, the conductive parts can be surely connected by the connecting part.
As described above, the present invention can provide the touch panel which has a small number of components, is low in cost, and capable of performing reliable operations.
Hereinafter, an exemplary embodiment of the present invention will be described with reference to
In these drawings, dimensions are partially enlarged for easy understanding of a configuration.
First conductive layer 12 is formed in such a manner that a plurality of square parts are connected in a roughly band-shaped form. In addition, a plurality of roughly square-shaped void parts are provided between adjacent first conductive layers 12, and a plurality of roughly rectangle-shaped conductive parts 13A made of light transmissive material such as indium tin oxide or tin oxide are formed in the void parts. Roughly rectangle-shaped conductive parts 13A are not connected but separated from each other. According to the present exemplary embodiment, first conductive layers 12 and conductive parts 13A are formed at the same time, so that they are made of the same material and have the same film thickness. As a result, it becomes possible to simplify steps. However, first conductive layer 12 and conductive part 13A may be formed separately from each other, so that they are made of different materials and have different film thicknesses. As a result, each of them can be made of optimal material and has an optimal thickness.
The plurality of conductive parts 13A are connected by a plurality of light transmissive connecting parts 13B in a horizontal direction perpendicular to first conductive layer 12, and thus a plurality of second light transmissive conductive layers are provided in a roughly band-shaped form. The horizontal direction is assumed to be a second direction. Connecting part 13B is formed in such a manner that a plurality of conductive fine wires made of material such as silver, copper, or carbon are dispersed in light transmissive ultraviolet curable resin made of material such as acrylate or methacrylate. The conductive fine wire has a diameter ranging from 10 nm to 300 nm, and a length ranging from 1 nm to 100 nm. Second conductive layers 13 and first conductive layers 12 are formed on the upper surface of substrate 11 with predetermined spaces between them.
Light transmissive insulating layer 13C made of resin material such as acrylate or methacrylate is formed between connecting part 13B and first conductive layer 12 by a method such as printing or exposing/developing. First conductive layer 12 and second conductive layer 13 are insulated from each other by insulating layer 13C.
In addition, light transmissive insulating layer 13C may be made of ultraviolet curable resin material such as acrylate or methacrylate.
In addition, in a case where connecting part 13B and insulating layer 13C are made of the same resin material, reflection can be minimized at an overlapping interface, and transmittance as the touch panel can be improved, so that a display element on a back surface can be easily recognized.
Reference numerals 14A and 14B represent a first electrode and a second electrode, respectively made of silver or carbon by printing, or made of copper foil by vapor deposition. One end of first electrode 14A is connected to an end part of first conductive layer 12, and one end of second electrode 14B is connected to an end part of second conductive layer 13. First electrode 14A and second electrode 14B are formed so as to extend in the horizontal direction in such a manner that the other end of first electrode 14A and the other end of second electrode 14B are positioned at a peripheral right end of substrate 11.
Reference numeral 15 represents a cover layer made of material such as acryl, polycarbonate, or epoxy. Cover layer 15 is formed on the upper surface of substrate 11 by printing or the like in such a manner that cover layer 15 covers the whole upper surface of substrate 11 except for the peripheral right end, and thus the touch panel is provided.
Next, a method for manufacturing the above touch panel will be described with reference to
As shown in
Then, an upper surface of conductive thin film 20 is covered with a film made of insulating resin such as dry film resist which has been formed so as to have patterns of first conductive layers 12 and conductive parts 13A. Then, conductive thin film 20 is soaked in a predetermined etching solution, and conductive thin film 20 positioned at unnecessary parts is removed with the patterned insulating resin film used as a mask. Thus, as shown in
Then, as shown in
Then, as shown in
Then, as shown in
Then, as shown in
Then, as shown in
In addition, cover layer 15 is formed on the upper surface of substrate 11 by printing or the like so as to cover the whole surface except for the peripheral right end, so that the touch panel shown in
In addition, when connecting part 13B is made of ultraviolet curable resin 21 as described above, a curing operation can be performed in a short time, which is preferable, but it may be made of resin other than ultraviolet curable resin 21, such as heat curable resin, according to a holding facility. Also, a light transmissive electron beam curable resin made of material such as acrylate or methacrylate can be used instead of ultraviolet curable resin 21. In case of using electron beam curable resin, an electron beam is used in exposing/developing method.
The touch panel thus configured is disposed on a front surface of a display element such as a liquid crystal display element, and thus mounted on an electronic device. First electrodes 14A and second electrodes 14B provided so as to extend at the peripheral right end of the touch panel are electrically connected to an electronic circuit (not shown) of the electronic device, through a flexible wiring plate or a connector (not shown).
In the above configuration, while a voltage is sequentially applied to first electrodes 14A and second electrodes 14B from the electronic circuit, an upper surface of cover layer 15 is touched and operated with a finger or the like, according to a display of the display element provided on a back surface of the touch panel. Thus, electrostatic capacity between first conductive layer 12 and second conductive layer 13 positioned at the operated part is changed, and the electronic circuit detects the operated part, so that various functions can be switched in the electronic device.
For example, under a condition that a plurality of menus are displayed on the display element on the back surface, the upper surface of cover layer 15 positioned above a desired menu is touched with a finger or the like. Electric charge is partially conducted to this finger, and capacity between first conductive layer 12 and second conductive layer 13 is changed at the operated part of the touch panel. When the electronic circuit detects the change in capacity, the desired menu can be selected.
Thus, according to the present exemplary embodiment, roughly band-shaped first conductive layers 12 and roughly band-shaped second conductive layers 13 extending in the direction perpendicular to first conductive layers 12 are disposed on the upper surface of one substrate 11 with the predetermined spaces provided between them. In this case, there is no need to use a plurality of substrates, the number of components can be reduced, and there is no need to overlap and attach the plurality of substrates to each other. In addition, each component possibly absorbs 0.5% to 20% of light, and generates interlayer interface reflection, so that when the number of the components is reduced, transmittance of the touch panel is improved. As a result, according to the touch panel thus formed, the display element on the back surface can be easily recognized, assembling is easy, and the cost is low.
As for second conductive layer 13, roughly rectangle-shaped conductive parts 13A are connected by connecting parts 13B made of ultraviolet curable resin in which the conductive fine wires are dispersed. Second conductive layer 13 is formed so as to extend in the direction perpendicular to first conductive layer 12. As a result, second conductive layer 13 can be formed at low cost by a simple method, and conductive parts 13A can be surely connected.
More specifically, compared with a case where connecting part 13B is formed of material such as indium tin oxide by sputtering or the like, connecting parts 13B can be formed by the simple method in which ultraviolet curable resin 21 is applied and cured on substrate 11, without needing facilities such as a vacuum device. Thus, conductive parts 13A can be surely connected by the conductive fine wires dispersed in connecting part 13B.
In addition, the above description has been given of the configuration in which insulating layer 13C is formed between conductive parts 13A so as to cover first conductive layer 12.
In addition, according to the present exemplary embodiment, second conductive layer 13 is composed of conductive parts 13A and connecting parts 13B for connecting conductive parts 13A. Instead of this, second conductive layer 13 may be formed into a roughly band-shaped form in which square parts are connected, and first conductive layer 12 may be formed in such a manner that conductive parts are connected by connecting parts. That is, first conductive layer 12 and second conductive layer 13 may be replaced with each other.
According to the present exemplary embodiment, first conductive layer 12 and conductive part 13A of second conductive layer 13 are made of the material such as indium tin oxide or tin oxide by sputtering or the like. Instead of this, material of first conductive layer 12 and conductive part 13A of second conductive layer 13 may be one having silver fine wires scattered in light transmissive acrylic resin, or light transmissive conductive resin material such as polythiophene or polyaniline.
According to the present exemplary embodiment, first conductive layer 12 is formed such that the square parts are connected, but instead of this, circular, ellipsoidal, polygonal, or rounded roughly polygonal parts may be connected. According to the present exemplary embodiment, conductive part 13A is in the roughly rectangular form, but instead of this, it may be in a circular, ellipsoidal, polygonal, or rounded roughly polygonal form.
In above description according to the embodiment, terms, such as “upper surface”, “lower surface”, and “above”, indicating directions merely indicate relative directions depending on the relative positional relationship of components, such as the substrate, the conductive layer, and the insulating layer, of the touch panel, and do not indicate absolute directions, such as a vertical direction.
Thus, according to the present exemplary embodiment, first conductive layers 12 having the roughly band-shaped form, and second conductive layers 13 extending in the roughly band-shaped form in the direction perpendicular to first conductive layers 12 are formed on the upper surface of substrate 11 with the predetermined spaces provided between them. Either first conductive layer 12 or second conductive layer 13 is composed of roughly rectangle-shaped conductive parts 13A, and connecting parts 13B made of ultraviolet curable resin in which the conductive fine wires are dispersed to connect conductive parts 13A. Thus, since first conductive layers 12 and second conductive layers 13 are formed on the upper surface of one substrate 11, the number of the components can be small, and the assembling can be easily performed. Furthermore, the touch panel in which conductive parts 13A can be surely connected by connecting parts 13B, and the reliable operation can be performed can be provided at low cost.
The touch panel according to the present invention has an advantageous effect of reducing the number of the components and ensuring low cost and reliable operations, and is useful for mainly operating various kinds of electronic devices.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-148246 | Jul 2012 | JP | national |
