Electrostatic capacitance-type input device, method of testing electrostatic capacitance-type input device, and driving device for electrostatic capacitance-type input device

An electrostatic capacitance-type input device includes: a plurality of first electrodes, which detect an input position, extending in a first direction in an input area on a substrate; a plurality of second electrodes, which detect an input POSITION, extending in a second direction intersecting with the first direction in the input area; a plurality of signal wirings that extend from one-side end portions of the first electrodes and one-side end portions of the second electrodes on the substrate; a test electrode that faces the other-side end portions of at least one of the first electrodes and the second electrodes through an insulating film on the substrate; and a test wiring that is electrically connected to the test electrode.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application claims priority to Japanese Priority Patent Application JP 2009-283727 filed in the Japan Patent Office on Dec. 15, 2009, the entire contents of which is hereby incorporated by reference.

BACKGROUND

The present application relates to an electrostatic capacitance-type input device that detects an input position based on a change in the electrostatic capacitance coupled with an input position detecting electrode, a method of testing the electrostatic capacitance-type input device, and a driving device for an electrostatic capacitance-type input device. Among electronic apparatuses such as cellular phones, car navigation systems, personal computers, ticket-vending machines, and banking terminals, there are apparatuses, in which an input device termed a touch panel is arranged on the surface of a liquid crystal device or the like, allowing a user to input information while referring to an image displayed in an image display area of the liquid crystal device. Among such input devices, electrostatic capacitance-type input devices, as schematically shown inFIG. 11, have a plurality of first electrodes211that extend in the X direction and are used for detecting an input position, a plurality of second electrodes212that extend in the Y direction and are used for detecting an input position, and a plurality of signal wirings27that extend from one-side end portions of the first electrodes211and one-side end portions of the second electrodes212on a substrate20and monitor electrostatic capacitance that is coupled with each of the first electrodes211and the second electrodes212through a signal wiring27. Thus, when a finger is in proximity to any of the first electrodes211and the second electrodes212, the electrostatic capacitance of the electrode to which the finger is in proximity increases by the amount corresponding to electrostatic capacitance generated between the finger and the electrode. Accordingly, the electrode to which the finger is in proximity can be specified.

In such electrostatic capacitance-type input devices, when a short circuit is formed in one spot in the first electrode211or the second electrode212, it is difficult to detect the input position in the corresponding row. Accordingly, detecting whether a short circuit is formed in the first electrodes211and the second electrodes212is important in terms of securing the reliability of the electrostatic capacitance-type input devices.

As a method of testing formation of a short circuit in the electrodes, a test method in which a sensor electrode is brought to be in proximity to a plurality of electrodes one after another, and coupled capacitance between the sensor electrode and the corresponding electrode is monitored is proposed (for example, see JP-A-2004-191381).

SUMMARY

However, according to the method described in JP-A-2004-191381, the sensor electrode is brought to be in proximity to a plurality of electrodes one after another by a SCARA robot. Accordingly, a test device of a large scale is necessary. In addition, in the case of an electrostatic-type input device, capacitance coupled with the first electrode211and the second electrode212is already present. Thus, even when formation of a short circuit occurs, a difference between the capacitance of a normal electrode and the capacitance of a short-circuited electrode is small. Therefore, there is a problem in that it is difficult to identify the occurrence of a short circuit.

Thus, it is desirable to provide an electrostatic capacitance-type input device, a method of testing the electrostatic capacitance-type input device capable of reliably detecting whether or not a short circuit is formed in the electrodes used for detecting an input position without using a large-scale test device, and a driving device for an electrostatic-type input device capable of implementing such a test method.

According to an embodiment, there is provided an electrostatic capacitance-type input device including: a plurality of first electrodes, which detect an input position, extending in a first direction in an input area on a substrate; a plurality of second electrodes, which detect an input position, extending in a second direction intersecting with the first direction in the input area; a plurality of signal wirings that extend from one-side end portions of the first electrodes and one-side end portions of the second electrodes on the substrate; a test electrode that faces the other-side end portions of at least one of the first electrodes and the second electrodes through an insulating film on the substrate; and a test wiring that is electrically connected to the test electrode.

In addition, according to another embodiment, there is provided a method of testing an electrostatic capacitance-type input device including a plurality of first electrodes, which detect an input position, extending in a first direction in an input area on a substrate, a plurality of second electrodes, which detect an input position, extending in a second direction intersecting with the first direction in the input area; and a plurality of signal wirings that extend from one-side end portions of the first electrodes and one-side end portions of the second electrodes on the substrate. A test electrode that faces the other-side end portions of at least one of the first electrodes and the second electrodes through an insulating film and a test wiring that is electrically connected to the test electrode are disposed. The above-described method includes the steps of: measuring capacitance values between the test wiring and the plurality of signal wirings; and determining that the electrode out of the first electrodes and the second electrodes, which has a capacitance value equal to or less than a set value, and to which the signal wirings are electrically connected is short-circuited.

In an embodiment, the test electrode that faces the other-side end portions of at least one of the first electrodes and the second electrodes through the insulating film on the substrate and the test wiring that is electrically connected to the test electrode are included. Accordingly, by measuring the capacitance values between the test wiring and a plurality of the signal wirings, it can be determined that formation of a short circuit occurs in the electrode to which the signal wiring having a capacitance value equal or less than the set value is electrically connected. According to such a configuration, in a case where capacitance is coupled with the first electrode or the second electrode, when a shot-circuit is formed, capacitance between the test wiring and the signal wirings is not detected at all or is detected to be extremely low. Accordingly, formation of a circuit in the electrode can be reliably detected even in a case where capacitance coupled with the first electrode or the second electrode is already present. In addition, since the capacitance values between the test wiring and the signal wirings that are formed on the substrate are measured, there is an advantage in that a large-scale test device is not necessary. Furthermore, since a capacitance value between the first electrode or the second electrode and the test electrode is constant and small, the detection of a position is not hindered by disposing the test electrode.

In an embodiment, it is preferable that the test electrode overlaps the other-side end portions in a thickness direction through the insulating film so as to face the other-side end portions. In such a case, since the first electrode or the second electrode and the test electrode can be combined with capacitance of an appropriate capacitance value, the capacitance value between the test wiring and the signal wirings can be reliably measured.

In an embodiment, it is preferable that a relay electrode that electrically connects the second electrodes disconnected in intersection portions to each other on the substrate is further included, the second electrodes are disconnected in the intersection portions with the first electrodes, and the test electrode is disposed at least in the other-side end portions of the second electrodes. In such a case, it can be detected whether or not a short circuit is formed in the second electrodes, in which formation of a short circuit may easily occur, out of the first electrodes and the second electrodes.

In an embodiment, it is preferable that the test electrode is disposed in the other-side end portion of the first electrodes and the other-side end portion of the second electrodes. In such a case, it can be detected whether formation of a short circuit occurs in both the first electrodes and the second electrodes.

In an embodiment, it is preferable that the test electrode is independently disposed for each of the other-side end portions, and the test wiring is electrically connected to a plurality of the test electrodes. In addition, in the embodiment, it is preferable that the test wiring is electrically connected to all the test electrodes. In such a case, since the number of the test wirings can be suppressed to a minimum, a space used for disposing the test wiring may be small.

In an embodiment, it is preferable that the test wiring extends so as to surround at least three sides of the input area. In such a case, since the test wiring can be used as a shield wiring, penetration of an electromagnetic wave noise into the input area can be prevented.

In an embodiment, it is preferable that a short-circuit testing unit that is electrically connected to the test wiring and the plurality of signal wirings is further included, and the short-circuit testing unit measures capacitance values between the test wiring and the plurality of signal wirings and determines that the electrode out of the first electrodes and the second electrodes, which has a capacitance value equal to or less than a set value, and to which the signal wirings are electrically connected is short-circuited. In such a case, formation of a short circuit can be detected by the electro-static capacitance-type input device without using a test device.

Such a test method can be performed by a driving device for an electrostatic capacitance-type input device. In other words, according to another embodiment, there is provided a driving device for an electrostatic capacitance-type input device including a plurality of first electrodes, which detect an input position, extending in a first direction in an input area on a substrate, a plurality of second electrodes, which detect an input position, extending in a second direction intersecting with the first direction in the input area; and a plurality of signal wirings that extend from one-side end portions of the first electrodes and one-side end portions of the second electrodes. The driving device includes: a plurality of signal terminals that output position detecting signals to the signal wirings; a driving unit that supplies position detecting signals to the signal terminals; a test terminal; a capacitance measuring unit that measures capacitance values between the test terminal and the plurality of signal terminals; and a short-circuit determining unit that determines whether or not there is the signal terminal having a capacitance value equal to or less than a set value based on a capacitance measuring result of the capacitance measuring unit. In such a case, formation of a short circuit can be detected by the driving device for an electrostatic capacitance-type input device without using a test device.

The electrostatic capacitance-type input device according to the embodiment, for example, can be used for configuring an input device-attached electro-optical apparatus. In the input device-attached electro-optical apparatus, an electro-optical panel used for generating an image is configured on a side of the substrate that is opposite to the input operation side thereof.

An electro-optical apparatus with the input device according to the embodiment can be used in electronic apparatuses such as a cellular phone, a car navigation system, a personal computer, a ticket-vending machine, and a banking terminal.

DETAILED DESCRIPTION

Embodiments of the present application will be described below in detail with reference to the drawings.

Embodiments

Entire Configuration of Input Device-Attached Electro-Optical Apparatus

FIGS. 1A to 1Care explanatory diagrams of an electrostatic capacitance-type input device according to an embodiment.FIG. 1Ais an explanatory diagram schematically showing the entire configuration of an input device-attached electro-optical apparatus including the electrostatic capacitance-type input device of this embodiment.FIG. 1Bis an explanatory diagram schematically showing the electric configuration of the electrostatic capacitance-type input device.FIG. 1Cis an explanatory diagram of an electric potential supplied to the electrostatic capacitance-type input device.FIGS. 2A and 2Bare explanatory diagrams schematically showing the cross-sectional configurations of input device-attached electro-optical apparatuses according to Embodiment 1 of the present application.FIG. 2Ais an explanatory diagram of a configuration example in which input position detecting electrodes are disposed on the first face side of a substrate that is located on the input operation side thereof.FIG. 2Bis an explanatory diagram of a configuration example in which the input position detecting electrodes are disposed on the second face side of the substrate that is located on a side opposite to the input operation side of the substrate.

As shown inFIG. 1A, generally, the input device-attached input apparatus100of this embodiment has an image generating device5that is configured by a liquid crystal device or the like and an electrostatic capacitance-type input device1disposed on a face of the image generating device5that is located on a side, from which display light is emitted, in an overlapping manner. The electrostatic capacitance-type input device1includes an input panel2(touch panel), and the image generating device5includes a liquid crystal panel serving as an electro-optical panel5a(display panel). In this embodiment, both the input panel2and the electro-optical panel5ahave a planar shape of a rectangle, and the center area of the electrostatic capacitance-type input device1and the input device-attached electro-optical apparatus100in the plan view is an input area2a. An area of the image generating device5and the input device-attached electro-optical apparatus100that overlaps the input area2ain the plan view is an image forming area. A flexible wiring substrate35is connected to the side of the input panel2on which an end portion20eis positioned. In addition, a flexible wiring substrate73is connected to the side of an electro-optical panel5aon which the end portion20eis positioned.

InFIGS. 1A and 1BandFIGS. 2A and 2B, the image generating device5is an active matrix-type liquid crystal display device of transmission type or semi-transmission reflection type. On a side (a side opposite to the display light emitting side) of the electro-optical panel5athat is opposite to a side on which the input panel2is disposed, a back light device (not shown in the figure) is disposed. The back light device, for example, has a light guiding plate, which has translucency, disposed on a side of the electro-optical panel5athat is opposite to the side on which the electrostatic capacitance-type input device1is disposed in an overlapping manner and a light source such as a light emitting diode that emits white light or the like toward a side end portion of the light guiding plate. After light emitted from the light source is incident from the side end portion of the light guiding plate, the light is emitted toward the electro-optical panel5awhile propagating inside the light guiding plate. Between the light guiding plate and the electro-optical panel5a, a sheet-shaped optical member such as a light scattering sheet or a prism sheet may be disposed.

In the image generating device5, on the display light emitting side of the electro-optical panel5a, a first polarizing plate81is disposed in an overlapping manner. In addition, on the opposite side of the electro-optical panel5a, a second polarizing plate82is disposed in an overlapping manner. The electro-optical panel5aincludes a translucent component substrate50that is disposed on a side opposite to the display light emitting side and a translucent opposing substrate60that is disposed on the display light emitting side so as to oppose the component substrate50. The opposing substrate60and the component substrate50are bonded together by a rectangular frame-shaped sealing member71, and a liquid crystal layer55is maintained within an area between the opposing substrate60and the component substrate50that is surrounded by the sealing member71. On a face of the component substrate50that faces the opposing substrate60, a plurality of pixel electrodes58are formed by a translucent conductive film such as an ITO (Indium Tin Oxide) film or an IZO (Indium Zinc Oxide) film. In addition, on a face of the opposing substrate60that faces the component substrate50, a common electrode68is formed by a translucent conductive film such as an ITO film. In addition, on the opposing substrate60, color filters are formed. In a case where the image generating device5is an IPS (In Plane Switching) type or an FFS (Fringe Field Switching) type, the common electrode68is disposed on the component substrate50side. The component substrate50may be disposed on the display light emitting side of the opposing substrate60. A driving IC75is built in an overhang area59of the component substrate50that overhangs from the edge of the opposing substrate60by using a COG technique, and the flexible wiring substrate73is connected to the overhang area59. On the component substrate50, a driving circuit may be formed simultaneously with a switching device disposed on the component substrate50.

Detailed Configuration of Electrostatic Capacitance-Type Input Device1

In the electrostatic capacitance-type input devices1shown inFIGS. 2A and 2B, the input panel2includes a translucent substrate20that is configured by a glass plate, a plastic plate, or the like. In this embodiment, a glass substrate is used as the substrate20. In a case where the substrate20is formed from a plastic material, as the plastic material, a translucent sheet having heat resistance such as PET (polyethylene terephthalate), PC (polycarbonate), PES (polyether sulfone), PI (polyimide), or a cyclic olefin resin including polynorbornene or the like may be used. Hereinafter, the side of the substrate20on which an electrode and the like, to be described below, are formed will be described as the first face20a, and the opposite side is described as the second face20b.

Described in detail later, in the electrostatic capacitance-type input devices1shown inFIGS. 2A and 2B, on the first face20aof the substrate20, the first translucent conductive film4a, an interlayer insulating film214, and the second translucent conductive film4bare formed from the lower layer side toward the upper layer side when viewed from the substrate20. Thus, input position detecting electrodes21are formed by the first translucent conductive film4aout of the first translucent conductive film4aand the second translucent conductive film4b. On the end portion20efrom among end portions20e,20f,20g, and20hof the substrate20, the flexible wiring substrate35is connected to the first face20a. To the input operation side of the substrate20, a translucent cover90having an insulating property is attached by using an adhesive agent90eor the like. In an area of the cover90that overlaps an outer area (the peripheral area2b) of the input area2aof the substrate20, a light shielding layer90ais printed. An area that is surrounded by the light shielding layer90ais the input area2a. The light shielding layer90aoverlaps the outer area of the electro-optical panel5aand shields light leaking from the light source of the image generating device5or the end portion of the light guiding plate. In addition, a conductive film99used for shield, in which a translucent conductive film such as an ITO film is formed on a translucent film, is arranged between the input panel2and the liquid crystal panel5a. In the configuration shown inFIG. 2B, the conductive film99and the substrate20are bonded together by an adhesive layer99eor the like.

Schematic Configuration of Electrodes, Etc. of Electrostatic Capacitance-Type Input Device1

FIG. 3is an explanatory diagram showing a schematic configuration of the substrate20that is used in the electrostatic capacitance-type input device1according to Embodiment 1 of the present application. In addition, inFIG. 3, the position of each corner portion of the input area2ais denoted by a mark having a letter “L” shape.

As shown inFIG. 3, according to the electrostatic capacitance-type input device1of this embodiment, on the first face20aof the substrate20, a plurality of the first electrodes211, which extend in the X direction (the first direction) in the input area2a, used for detection of an input position and a plurality of the second electrodes212, which extend in the Y direction (the second direction) intersecting with the X direction in the input area2a, used for detection of an input position are formed. The input position detecting electrodes21are formed by the first electrodes211and the second electrodes212. In addition, in a peripheral area2bof the first face20aof the substrate20corresponding to the outer side of the input area2a, signal wirings27extending from end portions of the first electrode211on one side and signal wirings27extending from end portions of the second electrodes212on one side are formed. In addition, portions of the signal wirings27that are positioned on the end portion20eare configured as the first mounting terminals24a.

In addition, according to the electrostatic capacitance-type input device1of this embodiment, in the peripheral area2bof the first face20aof the substrate20, test wirings29extending along the end portions20gand20fof the substrate20extend, and portions of the test wirings29that are located in the end portion20eare configured as the second mounting terminal24b. Here, between the other-side end portions212yof the second electrodes212that are located on the end portion20gside and the test wirings29, short-circuit detecting portions28that respectively detect formation of a short circuit in the second electrodes212are configured.

Detailed Configuration of Input Position Detecting Electrodes21and Signal Wirings27, Etc

Hereinafter, with reference toFIGS. 4 to 6, the configurations of the input position detecting electrodes21(the first electrode211and the second electrode212), the signal wiring27, and the like will be described in detail, and then, the configurations of a test wiring29and the short-circuit detecting portion28will be described in detail.

FIG. 4is an explanatory diagram showing in detail the planar configuration of the substrate20that is used in the electrostatic capacitance-type input device1according to Embodiment 1 of the present application.FIGS. 5A and 5Bare explanatory diagrams showing the cross-sectional configurations of the substrate20that is used in the electrostatic capacitance-type input devices1according to Embodiment 1 of the present application.FIG. 5Ais a cross-sectional view of the substrate20taken along line A1-A1′, andFIG. 5Bis a cross-sectional view of the substrate20taken along line B1to B1′. InFIG. 4, in order to allow each configuration to be easily understood, the number of the electrodes represented is decreased, and the electrodes are represented in an enlarged scale. In addition, inFIG. 4, the first translucent conductive film4ais denoted by a dashed-dotted line, the interlayer insulating film214is denoted by a dotted line, the second translucent conductive film4bis denoted by a solid line, and the wiring metal layer is denoted by a dashed two-dotted line. InFIG. 4, the position of each corner portion of the input area2ais denoted by a mark having a letter “L” shape.

As shown inFIG. 4andFIGS. 5A and 5B, according to the electrostatic capacitance-type input device1of this embodiment, on the first face20aside of the substrate20, the first translucent conductive film4a, the interlayer insulating film214, and the second translucent conductive film4bare sequentially formed from the lower layer side toward the upper layer side when viewed from the substrate20. In addition, on the first face20aside of the substrate20, in each portion of the first translucent conductive film4athat configures the signal wiring27, a metal film4cis formed on the upper face of the first translucent conductive film4a.

In this embodiment, the first translucent conductive film4ais configured by a polycrystalline ITO film. In addition, on the upper layer side of the first translucent conductive film4a, the interlayer insulating film214that is configured by a translucent insulating film such as a photosensitive resin film or a silicon oxide film is formed. In this embodiment, the second translucent conductive film4b, similarly to the first translucent conductive film4a, is configured by a polycrystalline ITO film. The metal film4cis formed from an alloy of silver, palladium, and copper or the like. On the entirety of the first face20aof the substrate20, a translucent underlying protection film that is composed of a silicon oxide film or the like may be formed. In such a case, the first translucent conductive film4a, the interlayer insulating film214, and the second translucent conductive film4bare sequentially stacked on the underlying protection film.

In the electrostatic capacitance-type input device1of this embodiment, the first translucent conductive film4a, first, is formed as a plurality of rhombic areas in the input area2a, and the rhombic areas configure pad portions211aand212a(large area portions) of the input position detecting electrodes21(the first electrode211and the second electrode212). The pad portions211aand212aare alternately arranged in the X direction and the Y direction. Of a plurality of the pad portions211a, the pad portions211athat are adjacent to each other in the X direction (the first direction) are connected through a connection portion211c, and the pad portion211aand the connection portion211cconfigure the first electrode211that extends in the X direction. In contrast, although a plurality of the pad portions212aconfigure the second electrode212extending in the Y direction (the second direction), a portion between the pad portions212athat are adjacent to each other in the Y direction, that is, the portion overlapping the connection portion211cincludes a disconnected portion218a. In addition, the first translucent conductive film4ais formed as a lower layer wiring271that configures the lower layer side of the signal wiring27in the peripheral area2b.

The interlayer insulating film214is formed in a large area from the input area2ato the peripheral area2b. In the interlayer insulating film214, contact holes214aare formed. The contact holes214aare formed in positions that overlap end portions of the pad portion212afacing each other through the disconnected portion218a.

The second translucent conductive film4bis formed as a relay electrode215in an area overlapping the contact hole214a.

In the peripheral area2b, the metal film4cis formed as an upper layer wiring272that configures the upper layer side of the signal wiring27.

In addition, on the upper layer side of the second translucent conductive film4b, a topcoat layer219that is formed from a photosensitive resin is formed on an approximately entire face of the substrate20.

In the electrostatic capacitance-type input device1configured as described above, the first electrode211and the second electrode212are formed by the same conductive film (the first translucent conductive film4a) and extend in directions intersecting with each other. Accordingly, on the substrate20, there is an intersection portion218in which the first electrode211and the second electrode212intersect with each other.

Here, regarding the first electrode211and the second electrode212, the first electrode211is connected in the X direction by the connection portion211c, which is configured by the second translucent conductive film4b, so as to extend even in the intersection portion218. In contrast, in the second electrode212, the disconnected portion218ais configured in the intersection portion218. However, in the intersection portion218, the relay electrode215is formed in the upper layer of the interlayer insulating film214. Thus, the relay electrode215electrically connects the pads212a, which are adjacent to each other through the disconnected portion218a, through the contact holes214aof the interlayer insulating film214. Accordingly, the second electrode212extends in the Y direction in the state of being electrically connected in the Y direction. In addition, the relay electrode215overlaps the connection portion211cthrough the interlayer insulating film214. Accordingly, there is no concern about formation of a short circuit.

The first electrode211and the second electrode212configured as described above include rectangle-shaped pad portions211aand212ahaving a large area in an area pinched by the intersection portions218. The connection portion211cpositioned in the intersection portion218of the first electrode211is in a small-width shape having a width smaller than that of the pad portions211aand212a. In addition, the relay electrode215is also formed in a small-width shape with a width smaller than that of the pad portions211aand212a.

Here, the lower layer wiring271extends from one-side end portion of the first electrode211that is located on one side or the other side in the X direction, and, on the upper layer thereof, the upper layer wiring272is formed. In addition, the lower layer wiring271extends from a one-side end portion of the peripheral area2bthat is located on one side (the side on which the first mounting terminals24aare located) in the Y direction, and on the upper layer thereof, the upper layer wiring272is formed.

Method of Detecting Input Position

As shown inFIG. 1B, in the electrostatic capacitance-type input device1of this embodiment, a driving IC10(a driving device or a short-circuit testing unit for an electrostatic capacitance-type input device) is connected to the first mounting terminals24aand the second mounting terminal24bof the input panel2through the flexible wiring substrate35. Here, the driving IC10includes the first terminal11a(signal terminal) that is electrically connected to the first mounting terminals24athrough the flexible wiring substrate35and a driving unit110that outputs position detecting signals VD shown inFIG. 1Cto the first terminals11a. In addition, the driving IC10includes a capacitance measuring unit120that measures the capacitance coupled with each of the plurality of the first terminals11a. Furthermore, the driving IC10includes the second terminal11b(a test terminal) that is electrically connected to the second mounting terminal24bthrough the flexible wiring substrate35and a short-circuit determining unit130that determines whether there is the first terminal11ahaving a capacitance value that is equal to or less than a set value based on the capacitance measuring result of the capacitance measuring unit120. The second terminal11band the short-circuit determining unit130are used for detecting a short circuit to be described later. Accordingly, the driving IC10also serves as a short-circuit testing unit as described below. In addition, although the driving IC10includes a ground terminal that outputs a ground electric potential to the input panel2, it is not directly related to an embodiment, and thus, the drawing and the description thereof are omitted here.

In the electrostatic capacitance-type input device1configured as described above, when the driving IC10shown inFIG. 1Boutputs a position detecting signal VD having a rectangular pulse shape shown inFIG. 1Cfrom the first terminal11a, in a case where capacitance is not parasitic on the input position detecting electrode21, a signal having a waveform denoted by a solid line shown inFIG. 1Cis detected from the first terminal11a. In contrast, when capacitance is parasitic on the input position detecting electrode21, as denoted by a dotted line shown inFIG. 1C, the waveform is distorted due to the capacitance. Accordingly, the driving unit110can detect whether or not capacitance is parasitic on the input position detecting electrode21. Therefore, according to this embodiment, electrostatic capacitance coupled with each of the input position detecting electrodes21is monitored by sequentially outputting the position detecting signals VD to a plurality of the input position detecting electrodes21. Thus, when a finger is in proximity to any of the plurality of the input position detecting electrodes21, the electrostatic capacitance of the input position detecting electrode21to which the finger is in proximity increases by the amount corresponding to the electrostatic capacitance generated between the finger and the input position detecting electrode. Accordingly, the electrode to which the finger is in proximity can be specified.

Thus, when formation of a short-circuit occurs in one spot of the input position detecting electrodes (the first electrodes211and the second electrodes212) in the substrate20, it is difficult to perform detection for the row thereof. Accordingly, in this embodiment, the configuration described below is employed, and formation of a short circuit in the second electrode212is detected, in which formation of a short circuit can easily occur out of the first electrode211and the second electrode212.

Configuration for Detecting Short-Circuit

In this embodiment, in order to detect formation of a short circuit in the second electrodes212, on the first face20aof the substrate20, a test electrode280is disposed that faces the other-side end portion212y(the end portion located on the side of the end portion20gof the substrate20) located opposite to the one-side end portion of the second electrode212, to which the signal wiring27is connected, through the interlayer insulating film214. Thus, a short-circuit detecting portion28is configured by a portion in which the other-side end portion212yof the second electrode212and the test electrode280face each other.

Here, the test electrode280is formed from the second translucent conductive film4band is formed in a reed shape extending toward the input area2a. Accordingly, the end portion of the test electrode280overlaps the other-side end portion212yof the second electrode212, which is formed from the first translucent conductive film4a, in the thickness direction through the interlayer insulating film214. Accordingly, the short-circuit detecting portion28is configured by capacitance coupled between the test electrode280and the second electrode212.

In addition, in the peripheral area2bof the first face20aof the substrate20, the test wiring29that extends along the end portions20gand20fof the substrate20extends, and the portion of the test wiring29located on the end portion20ebecomes the second mounting terminal24b.

The test wiring29is configured by a lower layer wiring291that is formed from the first translucent conductive film4aand an upper layer wiring292that is formed from a metal layer4cformed along the upper face of the lower layer wiring291. In a portion of the test wiring29along the end portion20e, the width dimension of the upper layer wiring292formed from the metal film4cis decreased, compared to that of the lower layer wiring291that is formed from the first translucent conductive film4a. Accordingly, a greater portion of the lower layer wiring291overhangs from the upper layer wiring292to the side on which the input area2ais located in the width direction. Thus, in this embodiment, a contact hole214bis formed in an area of the interlayer insulating film214that overlaps the portion in which the lower layer wiring291overhangs in the width direction from the upper layer wiring292, and the lower layer wiring291of the test wiring29and the test electrode280are electrically connected to each other through the contact hole214b.

Such a test electrode280can be formed as a test electrode that is common to the plurality of the second electrodes212. However, in this embodiment, the test electrodes280are formed so as to have one-to-one relationship with the plurality of the second electrodes212. Accordingly, a plurality of the test electrodes280are formed, and the test wiring29is electrically connected to the plurality of test electrodes280. In this embodiment, all the plurality of the test electrodes280are electrically connected to the common test wiring29. Accordingly, although there are a plurality of the second electrodes212, only one test wiring29is formed.

Principle of Detection of Short Circuit

FIG. 6is an explanatory diagram representing the principle of detection of a short circuit using the electrostatic capacitance-type input device1according to Embodiment 1 of the present application.

In the electrostatic capacitance-type input device1of this embodiment, in order to detect formation of a short circuit in the second electrode212by using the short-circuit detecting portion28including the above-described test electrode280and the test wiring29, the driving IC10shown inFIG. 1Bsequentially measures the capacitance values between the plurality of the first terminals11aand the second terminal11bby using the capacitance measuring unit120while sequentially outputting test signals having a pulse shape to the plurality of the first terminals11aas shown inFIG. 1C. Then, the short-circuit determining unit130determines whether or not there is a first terminal11awith a capacitance value equal to or less than a set value based on the capacitance measurement result of the capacitance measuring unit120.

In other words, as shown inFIG. 6, between the signal wiring27and the test wiring29, in addition to various types of resistance R1to R8, there are parasitic capacitance C4to C8between the second electrode212and an electrode adjacent thereto, capacitance C3of the short-circuit detecting portion28, parasitic capacitance C12between the test wiring29and the second electrode212, parasitic capacitance C2between the test wiring29and the signal wiring27, and the like. However, when the second electrode212is short-circuited, capacitance between the test wiring29and the signal wiring27is not detected at all. Alternatively, when the second electrode212is short-circuited, only extremely low capacitance is detected between the test wiring29and the signal wiring27. Accordingly, even in a case where capacitance coupled with the second electrode212already presents, the short-circuit determining unit130can reliably detect the formation of a short circuit in the second electrode212, whereby the driving IC10serves as the short-circuit testing unit.

Major Advantages of this Embodiment

As described above, the electrostatic capacitance-type input device1of this embodiment has the test electrode280that faces the other-side end portion212yof the second electrode212through the interlayer insulating film214and the test wiring29that is electrically connected to the test electrode280on the substrate20. Accordingly, by sequentially measuring capacitance values between the test wiring29and a plurality of the signal wirings27, it can be determined that a short circuit is formed in the second electrode212to which the signal wiring27having a capacitance value equal to or less than a set value is electrically connected. According to such a configuration, even in a case where other capacitance is coupled with the second electrode212, when formation of a short circuit occurs, capacitance between the test wiring29and the signal wiring27is not detected at all or extremely low capacitance is detected. Accordingly, even in a case where capacitance coupled with the second electrode212is already present, formation of a short circuit in the second electrode212can be reliably detected.

In addition, since it suffices that the capacitance values between the test wiring29and the signal wirings27that are formed on the substrate20are measured, there is an advantage in that a large-scale test device is not necessary. Furthermore, since a capacitance value between the second electrode212and the test electrode280is constant, and the capacitance value is small, the position detection is not hindered even in a case where the test electrode280is disposed.

In addition, according to this embodiment, the test electrode280overlaps the other-side end portion212yof the second electrode212in the thickness direction through the interlayer insulating film214. Accordingly, since the first electrode or the second electrode and the test electrode can be coupled with capacitance of an appropriate capacitance value, the capacitance values between the test wiring29and the signal wirings27can be reliably measured.

In addition, according to this embodiment, a structure in which the disconnected portion of the second electrode212is connected to the relay electrode215is employed. Accordingly, formation of a short circuit can occur comparatively easily in the second electrode212, than in the first electrode211. However, in order for the formation of a short circuit in the second electrode212to be detected, the electrostatic capacitance-type input device1of this embodiment has high reliability.

In addition, according to this embodiment, although the test electrode280is independently disposed for each second electrode212, the test wiring29is electrically connected to all the test electrodes280. Accordingly, there may be at least one test wiring29, and therefore it is advantageous for a space used for disposing the test wiring29to be small.

Furthermore, according to this embodiment, detection of a short circuit is performed by using the driving IC10that is used for position detecting. Thus, after the driving IC10is connected, in addition to being regularly performed during the manufacturing process of the electrostatic capacitance-type input device1and before shipment of the electrostatic capacitance-type input device1, detection of a short circuit can be regularly performed even in a case where the electrostatic capacitance-type input device1is used after shipment.

FIG. 7is an explanatory diagram showing a schematic configuration of a substrate20that is used in an electrostatic capacitance-type input device1according to Embodiment 2 of the present application. The basic configuration of this embodiment is the same as that of Embodiment 1. Thus, to each common part, the same reference sign is assigned, and detailed description thereof is omitted.

As shown inFIG. 7, according to the electrostatic capacitance-type input device1of this embodiment, similarly to Embodiment 1, on the first face20aof the substrate20, a plurality of the first electrodes211, which extend in the X direction (the first direction) in the input area2a, used for detection of an input position and a plurality of the second electrodes212, which extend in the Y direction (the second direction) intersecting with the X direction in the input area2a, used for detection of an input position are formed. The input position detecting electrodes21are formed by the first electrodes211and the second electrodes212. In addition, in a peripheral area2bof the first face20aof the substrate20corresponding to the outer side of the input area2a, signal wirings27extending from end portions of the first electrode211on one side and signal wirings27extending from end portions of the second electrodes212on one side are formed. In addition, portions of the signal wirings27that are positioned on the end portion20eare configured as the first mounting terminals24a.

In addition, in the peripheral area2bof the first face20aof the substrate20, a test wiring29extending along the end portions20gand20fof the substrate20extend, and portions of the test wiring29that are located in the end portion20eare configured as the second mounting terminal24b. Here, between the other-side end portions212yof the second electrodes212that are located on the end portion20gside and the test wiring29, the short-circuit detecting portions28that are described with reference toFIG. 4andFIGS. 5A and 5Bare configured. Accordingly, formation of a short circuit in the second electrode212can be tested.

Here, a test wiring29surrounds three sides on which the end portions20f,20g, and20hof the substrate20are located in the periphery of the input area2a. In addition, both end portions of the test wiring29that are located on the end portion20eof the substrate20become the second mounting terminals24b, and the second mounting terminals24bare formed on both sides of the first mounting terminals24apinched therebetween.

Accordingly, in this embodiment, similarly to Embodiment 1, formation of a short circuit in the second electrode212can be detected. In addition, during a period during which the electrostatic capacitance-type input device1is used, when a shield electric potential is applied to the test wiring29from the driving IC10shown inFIG. 1B, penetration of electromagnetic wave noise into the input area2afrom the periphery of the substrate20can be prevented. As the shield electric potential, the ground electric potential may be applied to the test wiring29. However, by applying a shield electric potential that has the same waveform (including the phase) as that of the position detecting signal VD shown inFIG. 1C, a state in which capacitance is not parasitic between the input position detecting electrode21and the test wiring29(shield wiring) can be realized. Therefore, even in a case where the shield wiring (the test wiring29) is disposed on the substrate20, detection of an input position by using the electrostatic capacitance method is not hindered.

FIG. 8is an explanatory diagram showing a schematic configuration of a substrate20that is used in an electrostatic capacitance-type input device1according to Embodiment 3 of the present application. The basic configuration of this embodiment is the same as that of Embodiment 1. Thus, to each common part, the same reference sign is assigned, and the description thereof is omitted.

As shown inFIG. 8, according to the electrostatic capacitance-type input device1of this embodiment, similarly to Embodiment 1, on the first face20aof the substrate20, a plurality of the first electrodes211, which extend in the X direction (the first direction) in the input area2a, used for detection of an input position and a plurality of the second electrodes212, which extends in the Y direction (the second direction) intersecting with the X direction in the input area2a, used for detection of an input position are formed. The input position detecting electrodes21are formed by the first electrodes211and the second electrodes212. In addition, in a peripheral area2bof the first face20aof the substrate20corresponding to the outer side of the input area2a, signal wirings27extending from end portions of the first electrode211on one side and signal wirings27extending from end portions of the second electrodes212on one side are formed. In addition, portions of the signal wirings27that are positioned on the end portion20eare configured as the first mounting terminals24a.

In addition, in the peripheral area2bof the first face20aof the substrate20, a test wiring29extending along the end portions20gand20fof the substrate20extend, and a portion of the test wirings29that are located in the end portion20eis configured as the second mounting terminal24b. Here, between the other-side end portions212yof the second electrodes212that are located on the end portion20gside and the test wiring29, the short-circuit detecting portions28that are described with reference toFIG. 4andFIGS. 5A and 5Bare configured.

Here, all the signal wirings27that extend from the second electrodes212extend on one side (the end portion20hside) in the X direction and are not present on the other side (the end portion20fside) in the X direction. Thus, in this embodiment, on the end portion20fside of the substrate20, the short-circuit detecting portion28described with reference toFIG. 4andFIGS. 5A and 5Bis configured also between the other-side end portion211xof the first electrode211that is located on the end portion20fside and the test wiring29.

Therefore, according to this embodiment, detection of a short circuit in both the first electrodes211and the second electrodes212can be performed.

FIG. 9is an explanatory diagram of a short-circuit detecting portion28that is formed in an electrostatic capacitance-type input device1according to Embodiment 4 of the present application. In the above-described Embodiments 1 to 3, a configuration in which the test electrode280overlaps the other-side end portion212yof the second electrode212in the thickness direction through the interlayer insulating film214is employed in configuring the short-circuit detecting portion28. In contrast, in this embodiment, as shown inFIG. 9, the short-circuit detecting portion28is configured by using a side end portion of the test wiring29that faces the other-side end portion212yof the second electrode212in the horizontal direction through the interlayer insulating film214as the test electrode280.

Even in a case where such a configuration is employed, the test electrode280and the other-side end portion212yof the second electrode212are coupled together due to fringe capacitance that is caused by a horizontal electric field applied between the test electrode280and the other-side end portion212yof the second electrode212. Accordingly, formation of a short circuit in the second electrodes212can be performed. In addition, according to the configuration shown inFIG. 9, there is an advantage in that a space in which the test electrode280is disposed can be further decreased.

Other Embodiments

In the above-described embodiments, a liquid crystal device is used as the image generating device5. However, as the image generating device5, an organic electroluminescent device or an electronic paper device may be used.

Examples of Mounting in Electronic Apparatus

Next, electronic apparatuses to which input device-attached electro-optical apparatuses100according to the above-described embodiments are applied will be described.FIG. 10Ashows the configuration of a mobile-type personal computer including the input device-attached electro-optical apparatus100. The personal computer2000includes the input device-attached electro-optical apparatus100as a display unit and a main body unit2010. In the main body unit2010, a power switch2001and a keyboard2002are disposed.FIG. 10Bshows the configuration of a cellular phone including the input device-attached electro-optical apparatus100. The cellular phone3000includes a plurality of operation buttons3001, scroll buttons3002, and the input device-attached electro-optical apparatus100as a display unit. By operating the scroll buttons3002, the screen displayed in the input device-attached electro-optical apparatus100is scrolled.FIG. 10Cshows the configuration of a personal digital assistant (PDA) to which the input device-attached electro-optical apparatus100is applied. The personal digital assistant4000has a plurality of operation buttons4001, a power switch4002, and the input device-attached electro-optical apparatus100as a display unit. When the power switch4002is operated, various types of information such as an address list or a schedule book are displayed in the input device-attached electro-optical apparatus100.

In addition, as examples of electronic apparatuses, to which the input device-attached electro-optical apparatus100is applied, other than the electronic apparatuses shown inFIGS. 10A to 10C, there are electronic apparatuses such as a digital still camera, a liquid crystal television set, a view finder-type or monitor direct-viewing-type video cassette recorder, a car navigation system, a pager, an electronic organizer, a calculator, a word processor, a workstation, a television phone, a POS terminal, a banking terminal, and the like. As a display unit of the above-described various electronic apparatuses, the above-described input device-attached electro-optical apparatus100can be applied.