# Patent

## Title
Touch panel substrate and electro-optical device

## Abstract

A sensor electrode (31) provided between an insulating substrate (21) and a counter electrode (27) is electrically connected to a grid-shaped metal bridge (35) via an insulating layer.

## Background
TECHNICAL FIELD
The present invention relates to a touch panel substrate that is used in an in-cell touch panel and an electro-optic device including such a touch panel substrate.
BACKGROUND ART
In recent years, there has been widespread use of electro-optic devices, such as display devices, each having an integration of display section and an input section for reduction in size of the devices. In particular, in the case of portable terminals such as mobile phones, PDAs (personal digital assistants), and laptop personal computers, there has been widespread use of display devices each including a touch panel that is capable of detecting the position of contact between a display surface and a finger or stylus brought into contact with the display surface.
There have conventionally been known various types of touch panel such as so-called resistive (pressure-sensitive) touch panels and capacitive touch panels. Among them, so-called capacitive touch panels have been in widespread use.
A capacitive touch panel detects the position of contact between a display surface and a finger or stylus by detecting a change in capacitance that occurred when the finger or stylus was brought into contact with the display surface. This makes it possible to detect the position of contact with a simple operation.
Further, unlike a resistive touch panel, the capacitive touch panel does not require the formation of two conductive films with an air layer sandwiched therebetween, and therefore does not suffer from interface reflection of outside light at the interface between an air layer and a conductive film.
However, the capacitive touch panel, which detects the position of contact by detecting a change in capacitance, might be incapable of correct detection of the position of contact due to a change in line of electric force that is caused by extrinsic noise received by the touch panel.
Touch panels that have conventionally been in widespread use are out-cell or on-cell touch panels (e.g., see Patent Literature 1) that are mounted on the outer sides of display panels.
However, the provision of a touch panel on the outer side of a display panel undesirably causes emission noise to be generated from the display panel when a touch panel operation is carried out while a display is being carried out, so that there is an increase in the amount of noise that is received by the touch panel.
For this reason, the provision of a touch panel on the outer side of a display panel might cause a reduction in SN ratio (signal-to-noise ratio), with the result that the touch panel deteriorates in detection performance and therefore wrongly detects the position of contact.
Further, the provision of a touch panel on the outer side of a display panel undesirably causes the resulting device to increase in thickness and weight due to the stacking of the touch panel on the display panel.
Moreover, the provision of a touch panel on the outer side of a display panel causes outside light to be reflected not only on a surface of the touch panel but also at the interface between the touch panel and the display panel, so that contrast and viewability are adversely affected. Further, the provision of a touch panel on the outer side of a display panel causes viewability to deteriorate due to the touch panel per se.
Under such circumstances, an in-cell touch panel, i.e., a touch panel incorporated in a cell of a display panel or the like, has been under development from the point of view of reduction in thickness and weight, improvement in viewability, and cost advantages, such as reduction in the number of components, which are brought about by making touch panels “in-cell” (e.g., see Patent Literatures 2, 3, and 5).
A typical example of an in-cell touch panel is a structure which constitutes an electro-optic device such as a display panel or a display device and which includes an array substrate such as a TFT (thin-film transistor) substrate, a counter substrate such as a CF (color filter) substrate, and a so-called sensor electrode so fabricated between the array substrate and the counter substrate as to serve as a position detecting electrode for detecting the position of contact with an object.
Patent Literatures 2, 3, and 5, disclose a sensor electrode sandwiched between an insulating substrate of a CF substrate and a transparent counter electrode made of ITO (indium tin oxide), with the CF substrate used as a touch panel substrate (i.e., an in-cell touch panel substrate) to constitute an in-cell touch panel.
FIG. 64 is a cross-sectional view showing a configuration of a display device described in Patent Literature 2, and FIG. 65 is a plan view showing a configuration of a sensor electrode as taken along the line H-H shown in FIG. 64.
As shown in FIG. 64, a display device 300 described in Patent Literature 2 includes a display panel 304, and the display panel 304 includes a TFT substrate 301, a CF substrate 302, and a liquid crystal layer 303 sandwiched between the TFT substrate 301 and the CF substrate 302.
The CF substrate 302 includes an insulating substrate 311, a counter electrode 319 (common electrode), and a CF layer 318 provided between the insulating substrate 311 and the counter electrode 319, and the CF layer 318 is constituted by a light blocking section 316 (BM) and a plurality of colored layers 317 (CF) provided between adjacent parts of the light blocking section 316. The CF substrate 302 further includes a first electrode layer 312 and a second electrode layer 314 provided as a sensor electrode between the CF layer 318 and the insulating layer 311, with an insulating layer 313 provided between the first electrode layer 312 and the second electrode layer 314.
As shown in FIGS. 64 and 65, the first electrode layer 312 has a line portion 312a that extends linearly along a first direction and a bulge portion 312b that bulges from the line portion 312a. Further, the second electrode layer 314 has a line portion 314a that extends linearly along a second direction perpendicular to the first direction and a bulge portion 314b that bulges from the line portion 314a. 
FIG. 66 is a cross-sectional view schematically showing a configuration of a main part of the CF substrate 302, which is used as a touch panel substrate to constitute an in-cell touch panel, of the display device 300 described in Patent Literatures 2 and 3, with the constituent layers stacked in the order shown. It should be noted that FIG. 66 is equivalent to a cross-sectional view schematically showing a configuration of a main part of the CF substrate 302 of the display device 300 shown in FIG. 64.
In Patent Literature 1, as shown in FIG. 64, an insulating layer 320 and a shield electrode 321 are provided between the CF layer 318 and the counter electrode 319 from the side of the CF layer 318. However, FIG. 66 omits to illustrate the insulating layer 320 and the shield electrode 321. Further, although FIG. 66 shows the light blocking section 316 (BM) and the colored layer 317 (CF) as if they are stacked, they are actually provided on substantially the same level as shown in FIG. 64.
It should be noted that Patent Literatures 2 and 3 disclose that the first electrode layer 312 and the second electrode layer 314 may be made, for example, of a metal patterned into a grid shape (mesh shape), instead of being made of a sheet transparent conductor.
Further, Patent Literature 5 discloses using a black matrix layer as one of a pair of conductive layers which are placed opposite each other with an insulating layer sandwiched therebetween and which constitute a sensor electrode.
CITATION LIST
Patent Literature 1

    Japanese Patent Application Publication, Tokukai, No. 2010-72584 A (Publication Date: Apr. 2, 2010)


Patent Literature 2

    Japanese Patent Application Publication, Tokukai, No. 2010-72581 A (Publication Date: Apr. 2, 2010)


Patent Literature 3

    Japanese Patent Application Publication, Tokukai, No. 2010-160745 A (Publication Date: Jul. 22, 2010)


Patent Literature 4

    U.S. Pat. No. 6,452,514 (Registration Date: Sep. 17, 2002)


Patent Literature 5

    Japanese Patent No. 3526418 (Registration Date: Feb. 27, 2004)


SUMMARY OF INVENTION
Technical Problem
However, in the case of a sensor electrode, such as that shown in FIG. 66 or described in Patent Literature 5, which has a two-layer structure obtained by stacking conductive layers with an insulating layer sandwiched therebetween, as in the case of the two-layer structure constituted by the first electrode layer 312 and the second electrode layer 314, the second electrode layer 314 and the counter electrode 319 are so close to each other that there is an increase in parasitic capacitance. An increase in parasitic capacitance might make it impossible to correctly detect a position, so that the touch panel might not operate normally.
Further, when the first electrode layer 312 and the second electrode layer 314 are made solely of a transparent conductor (i.e., a transparent electrode), there is an increase in interconnection resistance. This causes an increase in CR time constant (capacitor×resistor), so that the touch panel might not operate normally. Moreover, it undesirably takes high processing cost for the touch panel to be operable.
Alternatively, when the first electrode layer 312 and the second electrode layer 314 are made of a grid metal, there is a reduction in parasitic capacitance, as compared with the case where the first electrode layer 312 and the second electrode layer 314 are made of a sheet transparent electrode. However, even in this case, where the sensor electrode has a two-layer structure constituted by the first electrode layer 312 and the second electrode layer 314, the second electrode layer 314 and the counter electrode 319 are so close to each other that there is a high parasitic capacitance.
Moreover, when the first electrode layer 312 and the second electrode layer 314 are made of a grid metal, there is a reduction in detection signal, so that the touch panel might not operate normally.
Thus, the performance and operation of a touch panel are greatly affected by parasitic capacitance and interconnection resistance.
The present invention has been made in view of the foregoing problems, and it is an object of the present invention to provide a touch panel substrate which is high in position detection performance and is capable of carrying out a stable position detecting operation, and is used in an in-cell touch panel, and to provide an electro-optic device including such a touch panel substrate.
In particular, it is an object of the present invention to provide a touch panel substrate which is low in interconnection resistance and an electro-optic device including such a touch panel substrate. Further, it is a further object of the present invention to provide a touch panel substrate which is low in parasitic capacitance and an electro-optic device including such a touch panel substrate.
Solution to Problem
In order to attain the object, a touch panel substrate according to the present invention is a touch panel substrate that is used as one of a pair of substrates between which an electro-optic element is sandwiched and that is provided with a position detecting electrode which detects, according to a change in capacitance, a position given by coordinates indicating an object to be detected, the touch panel substrate including: an insulating substrate; an electro-optic element driving electrode which applies an electric field to the electro-optic element; and the position detecting electrode, the position detecting electrode being provided between the insulating substrate and the electro-optic element driving electrode and being insulated from the electro-optic element driving electrode, the position detecting electrode including at least a plurality of first electrodes which are arranged along a first direction and each of which is made up of a transparent electrode, the first electrodes at least being electrically connected to a grid of metal wires via an insulating layer.
According to the configuration, the position detecting electrode includes at least the plurality of first electrodes which are electrically connected to the grid of metal wires via the insulating layer, and therefore the resistance of the position detecting electrode can be reduced while the optical transmittance and the area of the transparent region are ensured. Therefore, mounting the touch panel substrate in a display panel makes it possible to reduce the resistance of the position detecting electrode while ensuring the aperture ratio of the display panel.
Moreover, it is possible to reduce the resistance of the position detecting electrode as described above, and this makes it possible to reduce the CR time constant.
Therefore, according to the configuration, it is possible to provide the touch panel substrate that is high in position detection performance and capable of carrying out a stable position detecting operation.
In order to attain the object, an electro-optic device of the present invention includes an electro-optic element and a pair of substrates between which the electro-optic element is sandwiched, one of the pair of substrates being the touch panel substrate described above.
According to the configuration, the above described touch panel substrate is used as one of the pair of substrates, and it is therefore possible to provide a touch-panel-integrated electro-optic device which (i) includes an in-cell touch panel, (ii) is high in position detection performance, and (ii) can carry out a stable position detecting operation.
Advantageous Effects of Invention
As above described, according to the touch panel substrate and the electro-optic device of the present invention, the position detecting electrode, which is sandwiched between the insulating substrate and the electro-optic element driving electrode, at least has the first electrodes that are electrically connected to the grid of metal wires via the insulating layer. With the configuration, the resistance of the position detecting electrode can be reduced while the optical transmittance and the area of the transparent region are ensured. Therefore, mounting the touch panel substrate in a display panel makes it possible to reduce the resistance of the position detecting electrode while ensuring the aperture ratio of the display panel.
Moreover, it is possible to reduce the resistance of the position detecting electrode as described above, and this makes it possible to reduce the CR time constant.
Therefore, according to the configuration, it is possible to provide (i) the touch panel substrate that is high in position detection performance, capable of carrying out a stable position detecting operation, and used in an in-cell touch panel and (ii) the electro-optic device which includes such a touch panel substrate.



BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a cross-sectional view schematically showing a configuration of a main part of a liquid crystal display device according to Embodiment 1.
FIG. 2 is a cross-sectional view schematically showing a configuration of a main part of a touch panel substrate according to Embodiment 1, with the constituent layers stacked in the order shown.
FIG. 3 is a plan view schematically showing an example of a schematic of a configuration of a main part of a touch panel layer of the touch panel substrate according to Embodiment 1.
FIG. 4 is an enlarged plan view of a part of the touch panel layer shown in FIG. 3.
FIG. 5 is a set of diagrams (a) and (b), the diagram (a) showing a cross-section of a main part of the touch panel substrate as taken along the line Y1-Y1 across the touch panel layer shown in FIG. 4, the diagram (b) showing a cross-section of a main part of the touch panel substrate as taken along the line X2-X2 across the touch panel layer shown in FIG. 4.
FIG. 6 is a plan view schematically showing a configuration of a metal bridge shown in FIG. 4.
FIG. 7 is a set of diagrams (a) and (b), the diagram (a) schematically showing lines of electric force of a sensor electrode with no object to be detected being in contact with the touch panel substrate according to Embodiment 1, the diagram (b) schematically showing lines of electric force of the sensor electrode with an object to be detected being in contact with the touch panel substrate.
FIG. 8 is a circuit diagram showing an example of a position detecting circuit of the liquid crystal display device according to Embodiment 1.
FIG. 9 is a timing chart showing signals applied to drive lines, respectively, of the liquid crystal display device according to Embodiment 1.
FIG. 10 is a timing chart showing a timing of driving of an in-cell touch panel of the liquid crystal display device according to Embodiment 1.
FIG. 11 is a diagram for explaining the states, in each step, of a sampling circuit and a reset switch according to Embodiment 1.
FIG. 12 is a cross-sectional view schematically showing a conventional display panel.
FIG. 13 is a diagram showing a driving circuit of a capacitive touch panel.
FIG. 14 is a set of simulated waveform charts schematically showing the operation of the driving circuit shown in FIG. 13.
FIG. 15 is a diagram collectively showing the conditions of electrodes in a touch panel substrate and simulated waveforms of detection signals.
FIG. 16 is another diagram collectively showing the conditions of electrodes in a touch panel substrate and simulated waveforms of detection signals.
FIG. 17 is a diagram collectively showing the conditions of electrodes in a touch panel substrate and simulated waveforms of detection signals.
FIG. 18 is a diagram collectively showing the conditions of electrodes in a touch panel substrate and simulated waveforms of detection signals.
FIG. 19 is a set of cross-sectional views (a) through (e) showing steps of a process for fabricating a touch panel substrate according to Embodiment 1, with the steps arranged in process sequence.
FIG. 20 is a plan view schematically showing a configuration of a main part of a touch panel layer of a touch panel substrate according to Embodiment 2.
FIG. 21 is a set of diagrams (a) and (b), the diagram (a) showing a cross-section of the touch panel substrate as taken along the line Y2-Y2 across the touch panel layer shown in FIG. 20, the diagram (b) showing a cross-section of the touch panel substrate as taken along the line X3-X3 across the touch panel layer shown in FIG. 20.
FIG. 22 is a plan view schematically showing a configuration of a metal bridge shown in FIG. 20.
FIG. 23 is a plan view showing a configuration of a main part of a touch panel layer of a touch panel substrate according to Embodiment 3.
FIG. 24 is a diagram showing a cross-section of the touch panel substrate as taken along the line X4-X4 across the touch panel layer shown in FIG. 23.
FIG. 25 is a plan view schematically showing a configuration of a metal bridge shown in FIG. 23.
FIG. 26 is a plan view showing a configuration of a main part of a touch panel layer of another touch panel substrate according to Embodiment 3.
FIG. 27 is a set of diagrams (a) through (c), the diagram (a) showing a cross-section of the touch panel substrate as taken along the line Y3-Y3 across the touch panel layer shown in FIG. 26, the diagram (b) showing a cross-section of the touch panel substrate as taken along the line X5-X5 across the touch panel layer shown in FIG. 26, the diagram (c) showing a cross-section of the touch panel substrate as taken along the line X6-X6 across the touch panel layer shown in FIG. 26.
FIG. 28 is a plan view schematically showing a configuration of a metal bridge shown in FIG. 26.
FIG. 29 is a plan view showing a configuration of a main part of a touch panel layer of a touch panel substrate according to Embodiment 4.
FIG. 30 is a set of diagrams (a) and (b), the diagram (a) showing a cross-section of the touch panel substrate as taken along the line Y4-Y4 across the touch panel layer shown in FIG. 29, the diagram (b) showing a cross-section of the touch panel substrate as taken along the line X7-X7 across the touch panel layer shown in FIG. 29.
FIG. 31 is a plan view showing a configuration of a main part of a touch panel layer of another touch panel substrate according to Embodiment 4.
FIG. 32 is a plan view showing a configuration of a main part of a touch panel layer having two disconnecting lines provided between each of electrodes arranged along the Y-axis on a metal bridge and an electrode adjacent to that electrode along the X-axis.
FIG. 33 is a set of diagrams (a) through (c), the diagram (a) showing a cross-section of the touch panel substrate as taken along the line Y5-Y5 across the touch panel layer shown in FIG. 32, the diagram (b) showing a cross-section of the touch panel substrate as taken along the line X8-X8 across the touch panel layer shown in FIG. 32, the diagram (c) showing a cross-section of the touch panel substrate as taken along the line X9-X9 across the touch panel layer shown in FIG. 32.
FIG. 34 is still another plan view showing a configuration of a main part of a touch panel layer of still another touch panel substrate according to Embodiment 4.
FIG. 35 is a plan view showing a configuration of a column of electrodes arranged along the Y-axis on the touch panel layer shown in FIG. 34, an intersection with the column of electrodes, and an area around the intersection.
FIG. 36 is a plan view collectively showing modifications of contact holes in a touch panel layer of a touch panel substrate according to Embodiment 4.
FIG. 37 is a cross-sectional view schematically showing a configuration of a main part of a touch panel substrate according to Embodiment 5, with the constituent layers stacked in the order shown.
FIG. 38 is a set of other cross-sectional views (a) and (b) each schematically showing a configuration of a touch panel substrate shown in FIG. 37 in which a touch panel layer 23 shown in FIG. 4 is provided.
FIG. 39 is a set of cross-sectional views (a) and (b) each schematically showing a configuration of a substrate 20 in which a touch panel layer 23 shown in FIG. 20 is provided in a touch panel substrate shown in FIG. 37.
FIG. 40 is a set of cross-sectional views (a) through (e) showing steps of a process for fabricating a touch panel substrate according to Embodiment 5, with the steps arranged in process sequence.
FIG. 41 is a plan view showing a configuration of a main part of a touch panel layer of a touch panel substrate according to Embodiment 6.
FIG. 42 is a plan view showing a configuration of a main part of a touch panel layer of another touch panel substrate according to Embodiment 6.
FIG. 43 is a set of diagrams (a) and (b), the diagram (a) showing a cross-section of the touch panel substrate as taken along the line Y6-Y6 across the touch panel layer shown in FIG. 42, the diagram (b) showing a cross-section of the touch panel substrate as taken along the line X10-X10 across the touch panel layer shown in FIG. 42.
FIG. 44 is a plan view schematically showing a configuration of a metal bridge shown in FIG. 42.
FIG. 45 is a set of cross-sectional views (a) through (e) showing steps of a process for fabricating a touch panel substrate according to Embodiment 7, with the steps arranged in process sequence.
FIG. 46 is a set of cross-sectional views (a) and (b) each schematically showing a configuration of a main part of a touch panel substrate according to Embodiment 7 in which a light blocking layer is provided between an insulating layer and a CF layer.
FIG. 47 is a cross-sectional view schematically showing a configuration of another touch panel substrate according to Embodiment 7.
FIG. 48 is a set of cross-sectional views (a) and (b) each schematically showing a configuration of a main part of a touch panel substrate according to Embodiment 7 in which a light blocking layer is provided between an insulating substrate and a sensor electrode.
FIG. 49 is a plan view showing another example of forming disconnecting lines in a metal bridge shown in FIG. 42.
FIG. 50 is a set of diagrams (a) and (b), (a) being a plan view schematically showing a configuration of a touch panel substrate according to Embodiment 8, (b) being a cross-sectional view of the touch panel substrate taken along the line I-I shown in (a) of FIG. 50.
FIG. 51 is a set of diagrams (a) and (b), (a) being a plan view schematically showing a configuration of a liquid crystal panel according to Embodiment 8, (b) being a cross-sectional view of the liquid crystal panel taken along the line II-II shown in (a) of FIG. 51.
FIG. 52 is a cross-sectional view schematically showing a configuration of another liquid crystal panel according to Embodiment 8.
FIG. 53 is a plan view showing a relation of connection between a light blocking layer 22 and a counter electrode 27 according to Embodiment 9.
FIG. 54 is a set of diagrams (a) through (d), (a) being a cross-sectional view taken along the line Y7-Y7 shown in FIG. 53, (b) being a cross-sectional view taken along the line Y8-Y8 shown in FIG. 53, (c) being a cross-sectional view taken along the line X10-X10 shown in FIG. 53, (d) being a cross-sectional view taken along the line X11-X11 shown in FIG. 53.
FIG. 55 is a set of cross-sectional views (a) through (f) schematically showing steps of a process for fabricating a touch panel substrate according to Embodiment 9, with the steps arranged in process sequence.
FIG. 56 is a set of diagrams (a) and (b), (a) being a plan view schematically showing a configuration of a touch panel substrate according to Embodiment 10, (b) being a cross-sectional view taken along the line III-III shown in (a) of FIG. 56.
FIG. 57 is a set of cross-sectional views (a) and (b) each schematically showing a configuration of a touch panel substrate according to Embodiment 11.
FIG. 58 is a set of cross-sectional views (a) through (f) showing steps of a process for fabricating a touch panel substrate according to Embodiment 11, with the steps arranged in process sequence.
FIG. 59 is a set of cross-sectional views (a) and (b) each schematically showing a configuration of a touch panel substrate according to Embodiment 12.
FIG. 60 is a set of cross-sectional views (a) through (f) showing steps of a process for fabricating a touch panel substrate according to Embodiment 12, with the steps arranged in process sequence.
FIG. 61 is a set of diagrams (a) and (b), (a) being a plan view showing a display driving terminal and a touch panel terminal of a liquid crystal panel according to Embodiment 12, (b) being an enlarged view of an encircled region of the touch panel terminal shown in (a) of FIG. 61.
FIG. 62 is another plan view showing a display driving terminal and a touch panel terminal of a liquid crystal panel according to Embodiment 12.
FIG. 63 is another plan view showing a display driving terminal and a touch panel terminal of a liquid crystal panel according to Embodiment 12.
FIG. 64 is a cross-sectional view showing a configuration of a display device described in Patent Literature 2.
FIG. 65 is a plan view showing a configuration of a sensor electrode in a cross-section taken along the line H-H shown in FIG. 64.
FIG. 66 is a cross-sectional view schematically showing a configuration of a main part of a color filter substrate of a display device described in Patent Literatures 2 and 3, with the constituent layers stacked in the order shown.



DESCRIPTION OF EMBODIMENTS
Embodiments of the present invention are described in detail below.
Embodiment 1
An embodiment of the present invention is described below with reference to FIG. 1 through (a) through (e) of FIG. 19.
The present embodiment is described below by taking a liquid crystal display device as an example of an electro-optic device including an in-cell touch panel. However, the present embodiment is not to be limited to such an example.
<Configurations of a Liquid Crystal Display Device and a Liquid Crystal Panel as Schematically Shown>
FIG. 1 is a cross-sectional view schematically showing a configuration of a main part of a liquid crystal display device according to the present embodiment.
As shown in FIG. 1, a liquid crystal display device 1 (display device) according to the present embodiment includes a liquid crystal panel 2 (display panel), a backlight 3 (illuminating device) for irradiating the liquid crystal panel 2 with light, and a driving circuit etc. (not illustrated).
Since the backlight 3 is configured in the same manner as has conventionally been configured, the following omits to describe a configuration of the backlight 3. As the backlight 3, a surface light source device such as an edge-type backlight or a direct-type backlight can be used as appropriate.
The liquid crystal display device 1 according to the present embodiment is a touch-panel-integrated liquid crystal display device that has an in-cell touch panel, i.e., a touch panel incorporated in a liquid crystal cell 4 (display cell) of the liquid crystal panel 2. Further, the liquid crystal panel 2 is a touch-panel-integrated liquid crystal panel which has an in-cell touch panel substrate, i.e., which has a touch panel incorporated in the liquid crystal cell 4 as mentioned above. The liquid crystal panel 2 has both an image display function and a capacitive touch panel function.
The liquid crystal cell 4 is sandwiched between polarization plates 5 and 6 (circular polarization plates) provided outside the liquid crystal cell 4. Further, for example, a wave plate 7 is sandwiched between the liquid crystal cell 4 and the polarization plate 5, and a wave plate 8 is sandwiched between the liquid crystal cell 4 and the polarization plate 6. For example, the polarization plates 5 and 6 are disposed so that their transmission axes are perpendicular to each other.
<Configuration of the Liquid Crystal Cell 4 as Schematically Shown>
The liquid crystal cell 4 includes, as an electrode substrate (array substrate, element substrate) and a counter substrate, a pair of substrates 10 and 20 placed opposite each other.
The liquid crystal cell 4 includes, as an electro-optic element, a liquid crystal layer 50 sandwiched between the pair of substrates 10 and 20. The liquid crystal layer 50 is a type of optically-modulated layer that is optically modulated by an electric field applied thereto, and is used as a medium layer for display.
The pair of substrates 10 and 20 are sealed with a seal material 60 provided on the edges of these substrates 10 and 20.
The substrate 20, which faces toward a display surface (which faces toward a viewer), is a touch panel substrate that has a capacitive touch panel function. The touch panel has a terminal area 40 so provided in the substrate 20 as to be outside of the seal material 60.
The terminal area 40 has an IC chip (not illustrated) mounted thereon as an electronic circuit, and has an FPC (flexible printed circuit) board or the like attached thereto as a film substrate for transmitting signals for image display, position detection, etc.
The IC chip includes a driving circuit to which wires, such as gate lines and source lines, of the substrate 10 are connected, a position detecting circuit for detecting the coordinate position of an object to be detected, and the like.
The substrates 10 and 20 include insulating substrates 11 and 21 made, for example, of transparent glass, respectively. It is only necessary, however, that of the pair of substrates 10 and 20, the substrate 20, which is used as a touch panel substrate and faces toward the display surface, be transparent, and the insulating substrate of the substrate 10, which faces toward the backlight 3, does not necessarily need to be transparent. Further, the substrates 10 and 20 have alignment films (not illustrated) provided on their opposed surfaces as needed.
The following describes a configuration of each of the substrates 10 and 20.
<Substrate 10>
The substrate 10 (first substrate) is an array substrate. A usable example of the substrate 10 is an active-matrix substrate such as a TFT (thin-film transistor) substrate.
The substrate 10 is configured such that a gate insulating film, a plurality of gate and source lines, switching elements such as TFTs (thin-film transistors), an interlayer insulating film, pixel electrodes, an alignment film, etc. (which are not illustrated) are provided over the insulating substrate 11.
As the array substrate, a well-known array substrate can be used. As such, the array substrate is not described or illustrated in detail here.
The liquid crystal panel 2 is not limited to any particular drive system (display system), and various systems such as the VA (vertical alignment) system and the TN (twisted nematic) system can be employed.
<Substrate 20>
The substrate 20 (second substrate) is a counter substrate that is placed opposite the substrate 10 (array substrate). A usable example of the substrate 20 is a CF substrate provided with CF (color filter) layers (colored layers) of different colors.
The substrate 20 is used as a touch panel substrate which has a sensor electrode (position detecting electrode) that detects, according to a change in capacitance, a position given by coordinates indicating an object to be detected, and which is incorporated into the liquid crystal call 4 to constitute an in-cell touch panel.
The sensor electrode detects, according to a change in capacitance, contact of the object to be detected with the display surface of the liquid crystal panel 2, thereby detecting a position given by coordinates indicating the object to be detected brought into contact with the display surface of the liquid crystal panel 2.
As such, the object to be detected is not to be particularly limited, provided that it is an object that causes a change in capacitance. A usable example of the object to be detected is a conductor such as a finger or a stylus.
FIG. 2 is a cross-sectional view schematically showing a configuration of a main part of the substrate 20, with the constituent layers stacked in the order shown.
First, a laminated structure of the substrate 20 is described below with reference to FIGS. 1 and 2.
<Laminated Structure>
As shown in FIGS. 1 and 2, the substrate 20 includes an insulating substrate 21, a touch panel layer 23, a resin layer 24, a counter electrode 27 (optical element driving electrode, common electrode), and an alignment film (not illustrated), with these constituent elements (members) stacked in the order named.
As shown in FIGS. 1 and 2, the touch panel 23 includes a sensor electrode 31 (position detecting electrode), an insulating layer 34, and a metal bridge 35 (metal wires) that is bridge-connected to the sensor electrode 31. The metal bridge 35 is electrically connected to the sensor electrode 31.
The sensor electrode 31, the insulating layer 34, and the metal bridge 35 are stacked on the insulating substrate 21 in this order.
Further, as shown in FIG. 2, the sensor electrode 31 includes a plurality of island-shaped electrodes 32 (first electrodes) and a plurality of island-shaped electrodes 33 (second electrodes). As shown in FIG. 2, these electrodes 32 and 33 are formed on the same level (i.e., in the same plane).
Further, as shown in FIG. 2, the resin layer 24 is constituted by a CF layer 26 and an insulating layer 25.
FIG. 3 is a plan view schematically showing an example of a schematic of a configuration of a main part of the touch panel layer 23 of the substrate 20. It should be noted that FIG. 3 schematically shows a configuration of the touch panel layer 23 in an input region of a touch panel in the substrate 20 (i.e., in a display region of the liquid crystal panel 2).
FIG. 4 is an enlarged plan view of a part of the touch panel layer 23 shown in FIG. 3.
FIG. 5 is a set of diagrams (a) and (b), the diagram (a) showing a cross-section of a main part of the substrate 20 as taken along the line Y1-Y1 across the touch panel layer 23 shown in FIG. 4, the diagram (b) showing a cross-section of a main part of the substrate 20 as taken along the line X2-X2 across the touch panel layer 23 shown in FIG. 4. It should be noted that FIG. 1 shows a cross-section of a main part of the liquid crystal panel 2 as taken along the line X1-X1 across the touch panel layer 23 shown in FIG. 4.
Further, FIG. 6 is a plan view schematically showing a configuration of the metal bridge 35 shown in FIG. 4.
In the touch panel layer 23 shown in FIGS. 3 and 4, the sensor electrode 31 includes, as the island-shaped electrodes and 33, a plurality of electrodes in the form of a sheet-shaped pattern (planar-shaped pattern) of rectangular shapes (square shapes in the example shown in FIGS. 3 and 4) as seen in plan view.
Of these electrodes 32 and 33, the electrodes 32 are arranged at intervals from each other along a given direction (first direction; in the present example, along the Y-axis).
Further, the electrodes 33 are arranged at intervals from each other along a direction intersecting the direction along which the electrodes 32 are arranged (along a second direction; in the present example, along the X-axis, which is perpendicular to the Y-axis, along which the first direction extends).
In the examples shown in FIGS. 3 and 4, the electrodes 32 and 33 are disposed so that one of the two diagonals of the rectangular shape of each of the electrodes 32 and 33 extends along the X-axis and the other one of the two diagonals extends along the Y-axis. This causes the electrodes 32 and 33 to appear to be alternately disposed in a checkered pattern when viewed diagonally as shown in FIG. 3.
These electrodes 32 and 33 are transparent electrodes made, for example, of a transparent conductive material such as an oxide. Examples of the transparent conductive material include ITO (indium tin oxide), IZO (indium zinc oxide), zinc oxide, tin oxide, etc.
Alternatively, the electrodes 32 and 33 may be transparent electrodes, such as metal thin-film electrodes made of graphene or the like or thin-film carbon electrodes, which keep their transparency by being thin films.
Since there is a trade-off between transmittance and the amount of electric power that is consumed by the backlight 3, it is desirable that the electrodes 32 and 33 be formed so that their transmittance is 70% or higher.
Thus, in the present embodiment, the optical transmittance of these electrodes 32 and 33 and the area of transparent regions of these electrodes 32 and 33 are ensured by forming these electrodes 32 and 33 of transparent electrodes in the form of a sheet-shaped pattern.
Further, as shown in FIGS. 3 and 4, the electrodes 33, which are adjacent to each other along the X-axis, are electrically connected to each other via connecting wires (relay electrodes) 36. This causes the electrodes 33 to be provided so that the electrodes 33 are joined together one after another along the X-axis.
The connecting wires 36 can be made, for example, of the same material as that of which the electrodes 32 and 33 are made.
This allows the connecting wires 36 to be formed at the same time as the electrodes 33 and on the same level as the electrodes 33 to serve as connecting parts via which the electrodes 33 are joined.
It should be noted, however, that the electrical connections between the electrodes 33, which are adjacent to each other along the X-axis, do not necessarily have to be made via the connecting wires 36, which are made of the same material as that of which the electrodes 33 are made, and as long as the electrodes 33, which are adjacent to each other along the X-axis, are electrically connected to each other, there are no particular limitations on the way in which they are connected or on the means by which they are connected.
Meanwhile, in the plane in which the electrodes 32 and 33 are formed, as shown in FIGS. 3 and 4, the electrodes 32 are disposed along Y-axis in such a way as to be isolated from each other.
The metal bridge 35 is provided so that the insulating layer 25 (see FIGS. 1 and 2) is sandwiched between (i) the electrodes 32 and 33 and the connecting wires 36 and (ii) the metal bridge 35.
In FIGS. 3 and 4, the metal bridge 35 used is a grid of metal wires. It should be noted that FIGS. 3 and 4 show, as an example of the grid of metal wires, a metal wire netting (metal mesh) having a plurality of linear wires extending in a net-like fashion along the Y-axis and the X-axis.
The metal bridge 35 according to the present embodiment serves also as a light blocking layer which covers the space between pixels. Therefore, no black matrix (BM) is provided in the present embodiment. According to the present embodiment, therefore, it is possible to reduce processing cost for a single layer of the BM.
It should be noted that those linear wires which extend along the Y-axis are hereinafter referred to as “Y-wires” (vertical wires) and those linear wires which extend along the X-axis are hereinafter referred to as “X-wires” (horizontal wires).
On the electrodes 32 and 33, the insulating layer 34 is provided in a solid state, for example, all over a surface of the insulating substrate 21 over which the touch panel layer 23 is stacked, in such a way as to entirely cover these electrodes 32 and 33.
The insulating layer 34 has contact holes 37 provided therein via which the electrodes 32, which are arranged along the Y-axis, are electrically connected to the metal bridge 35.
At least one (one in the example shown in FIG. 4) of these contact holes 37 is provided for each of the electrodes 32.
The metal bridge 35 makes bridge connections between the electrodes 32, which are arranged along the Y-axis, via the contact holes 37, which are provided for each separate electrode 32.
Further, the insulating layer 34 has contact holes 38 provided therein via which the electrodes 33 are electrically connected to the metal bridge 35.
At least one (two in the example shown in FIG. 4) of these contact holes 38 is provided for each of the electrodes 33.
The metal bridge 35 makes bridge connections between the electrodes 33 via the contact holes 38.
The present embodiment, in which the metal bridge 35 makes a bridge connection between electrodes 33 via at least one contact hole provided in the insulating layer 34, makes it possible for bridge connections to be easily made by the metal bridge 35, which is in the form of a grid as mentioned above. This allows a simplification of a process and therefore a reduction in processing cost.
The metal bridge 35 has a disconnection between each of the electrodes 32 and an electrode 33 adjacent thereto, so that no electricity travels between the electrode 32 and the electrode 33.
Provided in the metal bridge 35 so as to be located between each of the electrodes 32, which are arranged along the Y-axis, and an electrode 33 adjacent thereto along the X-axis is a single disconnecting line 39 that extends along the pattern of these electrodes 32 and 33.
As shown in FIGS. 3, 4, and 6, these disconnecting lines 39 divide the metal bridge 35 into metal wiring parts 35a electrically connected to the respective electrodes 32 and metal wiring parts 35b electrically connected to the respective electrodes 33.
Of the electrodes 32 and 33 electrically connected to the metal bridge 35 via the contact holes 37 and 38, respectively, only those electrodes 32 arranged along the Y-axis are connected to each other along the Y-axis via the metal bridge 35. The electrodes 32 and 33 are insulated from each other by disconnecting lines 39 provided between the electrodes 32 and 33, and those ones of the electrodes 32 which are adjacent to each other along the X-axis via electrodes 33 are insulated from each other by disconnecting lines 39 provided between the electrodes 32 and 33.
Therefore, the electrodes 32, which are arranged along the Y-axis, are connected to each other along the Y-axis via the metal bridge 35. Further, the electrodes 33, which are arranged along the X-axis, are connected to each other along the X-axis via the connecting wires 36.
A column of electrodes 32 connected along the Y-axis and a row of electrodes 33 connected along the X-axis intersect each other at each connection part between electrodes 32 and 33 as a column of Y electrodes that extends along the Y-axis and a row of X electrodes that extends along the X-axis. It should be noted that a plurality of columns of electrodes 32, i.e., Y electrodes, are arranged along the X-axis and a plurality of rows of electrodes 33, i.e., X electrodes, are arranged along the Y-axis.
When the electrodes 32 are used as drive electrodes (driving electrodes, transmitting electrodes), the electrodes 33 are used as sense electrodes (detecting electrodes, receiving electrodes), or vice versa. That is, when the columns of electrodes 32 are used as drive lines, the rows of electrodes 33 are used as sense lines, or vice versa.
<Position Detecting Operation>
The following describes a position detection operation in which the touch panel detects the position of an object to be detected.
(a) of FIG. 7 is a diagram schematically showing lines of electric force of the sensor electrode 31 with no object to be detected being in contact with the substrate 20, and (b) of FIG. 7 is a diagram schematically showing lines of electric force of the sensor electrode 31 with an object to be detected being in contact with the substrate 20. It should be noted that (b) of FIG. 7 shows lines of electric force, for example, with a fingertip being in contact with the substrate 20 as an object to be detected.
It should be noted that the metal bridge 35 is electrically connected to the sensor electrode 31 and does not affect lines of electric force of the sensor electrode 31. Therefore, (a) and (b) of FIG. 7 omit to illustrate the insulating layer 34 and the metal bridge 35 of the touch panel layer 23, the CF layer 26, the counter electrode 27, etc.
To the electrodes 32 and 33, drive voltages are applied from a driving circuit section (not illustrated), respectively. When either the electrodes 32 or 33 (e.g., the electrodes 33) are used as drive electrodes, the other electrodes (e.g., the electrodes 32) are used as sense electrodes.
Application of drive voltages to these electrodes 32 and 33 causes capacitors to be formed via the insulating substrate 21, the insulating layer 25, etc. between the electrodes 32 and 33, so that such lines of electric force as those shown in (a) of FIG. 7 are formed.
In such a state, bringing a fingertip 70, i.e., a conductor, into contact with the surface of the substrate 20 as an object to be detected, as shown in (b) of FIG. 7, causes a capacitor 71 to be formed between the human body (fingertip 70) and the electrodes 32 and 33, with the result that some of the lines of electric force are grounded via the fingertip 70. This indicates that there is a big change in capacitance between the electrodes 32 and 33 in the part touched by the fingertip 70, and the position touched by the fingertip 70 can be detected by detecting the change.
That is, the X-coordinate of the fingertip 70 on the surface of the substrate 20 is detected by the electrodes 32 constituting electrode 32 columns extending along the Y-axis and arranged along the X-axis. Further, the Y-coordinate of the fingertip 70 on the surface of the substrate 20 is detected by the electrodes 33 constituting electrode 33 rows extending along the X-axis and arranged along the Y-axis.
<Driving Circuit>
In the present embodiment, the position detecting circuit for detecting the coordinate position of an object to be detected may be a well-known circuit (e.g., see Patent Literature 4), but is not to be particularly limited.
As an example of a position detecting circuit of the liquid crystal display device 1 according to the present embodiment, the following describes, with reference to FIGS. 8 through 11, an example of a position detecting circuit of a reciprocally-capacitive type on which most capacitive touch panels are based.
FIG. 8 is a circuit diagram showing an example of a position detecting circuit of the liquid crystal display device 1 according to the present embodiment.
In FIG. 8, the rows of electrodes 33 as shown in FIGS. 3 and 4 correspond to drive lines DL1, DL2, . . . , and DLn, and the columns of electrodes 32 as shown in FIGS. 3 and 4 correspond to sense lines (n), respectively.
Formed at an intersection between each of the drive lines DL1, DL2, . . . , and DLn and each of the sense lines (n) is a variable capacitor whose capacitance (Cx) varies by contact with an object to be detected such as the fingertip 70.
A position detecting circuit 100 shown in FIG. 8 includes a drive-line driving circuit 101, a sense-line driving circuit 102, a touch panel controller (control circuit of the touch panel) 103, and a timing controller 104 of the liquid crystal panel 2.
As shown in FIG. 8, the drive-line driving circuit 101 applies signals of predetermined waveforms to the drive lines DL1, DL2, . . . , and DLn in sequence. The drive-line driving circuit 101 applies signals of predetermined waveforms in an order from the drive line DL1 to the drive line DLn by sequential driving.
FIG. 9 is a timing chart showing signals applied to the drive lines DL1, DL2, . . . , and DLn, respectively.
Further, the sense-line driving circuit 102 includes, for each sense line (n), a sampling circuit 111, a storage capacitor 112, an output amplifier 113, a reset switch 114, and measuring means 115.
The touch panel controller 103 receives a gate clock signal GCK and a gate start pulse GSP from the timing controller 104 of the liquid crystal panel 2, determines whether the liquid crystal panel 2 is in a writing period or in a pause period, and, in a case where the liquid crystal panel 2 is in a pause period, sends, to the drive-line driving circuit 101, a start signal for starting to apply signals of predetermined waveforms to the drive lines DL1, DL2, . . . , and DLn in sequence.
Further, the touch panel controller 103 outputs a sampling signal and a reset signal to the sampling circuit 111 and the reset switch 114, respectively.
FIG. 10 is a timing chart showing a timing of driving of the in-cell touch panel of the liquid crystal display device 1.
In FIG. 10, at a timing before the signal applied to the drive line DL1 and the sampling signal are raised to a high level, the reset signal is raised to a high level. This causes the storage capacitor 112 to be grounded, so that the storage capacitor 112 is reset.
Then, after the reset signal has been dropped to a low level and before the signal applied to DL1 is raised to a high level, the sampling signal is raised to a high level. This causes the sampling circuit 111 to shift in state from 0 to 1, so that the output from the sense line (n) is supplied to the storage capacitor 112 via the sampling circuit 111.
When the signal applied to the drive line DL1 is raised to a high level with the sampling signal at a high level, there occurs a charge transfer toward the storage capacitor 112, so that it is possible to, by dropping the sampling signal to a low level with the signal applied to the drive line DL1 being at a high level, maintain (hold) the charge even when the signal applied to the drive line DL1 is dropped to a low level.
In the present embodiment, since the number of integrations Nint is 4 as shown in FIG. 8, the capacitance is measured by the measuring means 115 via the output amplifier 113 after the charge transfer and maintenance (hold) have been repeated four times.
After the measurement, the reset signal is raised again to a high level. This causes the storage capacitor 112 to be grounded, so that the storage capacitor 112 is reset.
FIG. 11 is a diagram for explaining the states of the sampling circuit 111 and the reset switch 114 in each step.
As shown in FIG. 11, STEP A is a case where the whole reset is performed. In this case, the sampling circuit 111 is in a state of 0. This causes the sense line (n) to be grounded, and the reset switch 114 causes the storage capacitor 112 to be grounded, so that the storage capacitor 112 is reset.
STEP B is a dead time (DEADTIME) between a point in time where the reset signal was dropped to a low level and a point in time where the sampling signal is raised to a high level.
STEP C represents a charge transfer state in which the sampling circuit 111 is in a state of 1 and the output from the sense line (n) is supplied to the storage capacitor 112 via the sampling circuit 111.
STEP D is a dead time (DEADTIME) between a point in time where the sampling signal was dropped to a low level and a point in time where the signal applied to the drive line DL1 is dropped to a low level.
In STEP E, the sampling circuit 111 is in a state of 0, and the sense line (n) and the storage capacitor 112 are maintained (held) electrically separated from each other.
Then, after the STEPS B to E have been repeated four times, the capacitance is measured by the measuring means 115 via the output amplifier 113 in STEP F, with the sampling circuit 111 maintained in a state of 0 and with the sense line (n) and the storage capacitor 112 electrically separated from each other.
<Parasitic Capacitance>
Next, effects on the performance of the touch panel by parasitic capacitances that are formed between the sensor electrode (position detecting electrode) and the counter electrode are described with reference to FIGS. 12 through 14.
FIG. 12 is a cross-sectional view schematically showing a conventional display panel. FIG. 13 is a diagram showing a driving circuit of a capacitive touch panel. FIG. 14 is a set of simulated waveform charts schematically showing the operation of the driving circuit. It should be noted that for the simulation, MSC Software's “Patran” (product name) was used.
In FIGS. 12 and 13, CD-S is a touch-detecting capacitor that is formed between a drive electrode (e.g., a first electrode layer) and a sense electrode (e.g., a second electrode layer) of the touch panel, and since its capacitance varies depending on whether or not a fingertip or the like is in contact with the touch panel, the capacitor is described as a variable capacitor.
It should be noted that in FIG. 13, the drive line corresponds to the output terminal of a drive electrode, the sense line corresponds to the output terminal of a sense electrode, and the CITO line corresponds to the output terminal of the counter electrode.
The position detecting circuit has an integrated circuit constituted by an operational amplifier and a capacitor CINT, and an output indicating whether or not a fingertip or the like is in contact is obtained as VOUT from this integrated circuit. CD-C is a parasitic capacitor that is formed between the drive electrode and the counter electrode, and CC-S is a parasitic capacitor that is formed between the sense electrode and the counter electrode. Rsence is the resistance of the position detecting electrode (sense electrode), and RCITO is the resistance of the counter electrode.
In a structure (so-called out-cell type) where the touch panel is provided outside the display panel, the dominant current pathway is a pathway indicated by the arrow F1 in FIG. 13. In an in-cell type, as in the present embodiment, where the touch panel is provided inside the display panel (in the present embodiment, the liquid crystal panel 2), there exists a further parasitic current pathway indicted by the arrow F2.
In (a) and (b) of FIG. 14, the thick line P indicates the voltage waveform of the drive line, and the thin line Q indicates the voltage waveform of the output voltage VOUT. As shown in (a) and (b) of FIG. 14, it is shown that since in a case where the resistance of the counter electrode is high (e.g., RCITO=390Ω), the CR time constant (capacitor×resistor) increases due to the effect of the parasitic current pathway indicated by the arrow F2 in FIG. 13, it takes a long time to converge to its original output voltage (see (b) of FIG. 14). This causes an increase in integral time and accordingly a reduction in the number of integrals, thus causing a reduction in SN ratio (signal-to-noise ratio). This causes deterioration in detection performance of the touch panel.
Therefore, in the case of an in-cell touch panel, it is necessary to, in order to enhance the detection performance of the touch panel, to lower any of the following: the capacitance of the parasitic capacitor CD-C that is formed between the drive electrode and the counter electrode, the capacitance of the parasitic capacitor CC-S that is formed between the sense electrode and the counter electrode, and the resistance of the position detecting electrode (e.g., the resistance Rsence of the sense electrode), and the resistance RCITO of the counter electrode.
For this purpose, the present embodiment distances the electrodes 32 and 33 and the counter electrode 27 as much as possible from each other by forming the electrodes 32 and 33 in the same plane. This makes it possible to reduce the parasitic capacitance between the sensor electrode and the counter electrode in comparison with a conventional case where the X electrodes and the Y electrodes that are used as the drive electrodes and the sense electrodes are provided separately as the first electrode layer and the second electrode layer.
For this reason, the present embodiment makes it possible to provide: an in-cell touch panel which is high in position detection performance and capable of carrying out a stable position detecting operation; and a substrate 20 that serves as a touch panel substrate which is used in such an in-cell touch panel and which is high in position detection performance and capable of carrying out a stable position detecting operation.
Further, according to the present embodiment, forming the electrodes 32 and 33 in the same plane allows the electrodes 32 and 33 to be formed of the same material at the same time. This makes it possible to reduce processing cost.
<Relationship Between the Area of the Sensor Electrode and Detection Signals>
Next, a relationship between the area of the sensor electrode (position detecting electrode) and detection signals (position detection signals) is described below with reference to FIGS. 15 through 18.
FIGS. 15 through 18 are each a diagram collectively showing the conditions of electrodes and simulated waveforms of detection signals.
In each of these simulations, as shown in FIGS. 15 through 18, respectively, position detection signals in a case where a cover glass was provided with a sense electrode and a drive electrode and a counter electrode made of ITO (counter ITO electrode) was placed opposite the sense and drive electrodes with an insulating layer sandwiched therebetween were measured.
As is evident from the results shown in FIGS. 15 through 18, in the case of a sensor electrode formed on a counter ITO electrode, the lower the density of the sensor electrode (density of the sense and drive electrodes) is, the lower the magnitude (intensity) of the detection signal is.
Therefore, in order for the detection signal to ensure its magnitude, it is desirable that the sensor electrode be in a solid planar-shaped pattern as shown in FIG. 15.
Further, in such a case where the sensor electrode is in a solid planar-shaped pattern, it is desirable that the sensor electrode be in the form of a transparent electrode, so that an aperture ratio for display can be ensured.
However, an electrode made of a transparent conductive material is higher in resistance than that of a metal electrode. Further, a metal thin-film electrode made of graphene or the like is thinned for transparency, and as such, is higher in resistance than a metal electrode that is in a non-transparent state.
For this reason, in the present embodiment, as mentioned above, the electrodes 32 and 33 are electrically connected via the insulating layer 34 to the metal bridge 35 that is a grid of metal wires.
The metal bridge 35 has (i) a light blocking function as a BM and (ii) a function to reduce resistance of the sensor electrode 31. According to the present embodiment, it is possible to reduce processing cost by not providing another BM, and to reduce the resistance of the electrodes 32 and 33 while ensuring the aperture ratio of the display panel in which the substrate 20 is provided.
Further, since the resistance of the electrodes 32 and 33 can be reduced as mentioned above, the CR time constant can be reduced.
Therefore, the present embodiment makes it possible to provide an in-cell touch panel and a touch panel substrate that are high in position detection performance and capable of carrying out a stable position detecting operation.
Further, since the present embodiment can distance the electrodes 32 and 33 and the counter electrode 27 as much as possible from each other by forming the electrodes 32 and 33 in the same plane, a parasitic capacitance between the electrodes 32 and 33 and the counter electrode 27 can be reduced even in a case where the electrodes 32 and 33 are in a planar-shaped pattern. This makes it possible to reduce the parasitic capacitance while ensuring the magnitude of the detection signal.
Further, since the metal bridge 35 is in the shape of wires (i.e., in a linear-shaped pattern), the parasitic capacitance between the metal bridge 35 and the counter electrode 27 is small. For this reason, providing the metal bridge 35 so that it is closer to the counter electrode 27 than the sensor electrode 31 as shown in FIGS. 1 and 2 makes it possible to provide an in-cell touch panel and a touch panel substrate that are high in position detection performance and capable of carrying out a stable position detecting operation.
<Method for Producing a Liquid Crystal Panel 2>
The following describes a method for producing a liquid crystal panel 2 according to the present embodiment.
<Process for Fabricating a Substrate 10>
The substrate 10 is, for example, an active matrix substrate. The substrate 10 is fabricated by forming components such as gate lines, source lines, TFTs, and pixel electrodes on an insulating substrate 11 by known techniques and then forming an alignment film as needed.
Such an active matrix substrate can be produced by a process that uses known techniques. As such, the process is not described in detail here.
<Process for Fabricating a Substrate 20>
The following describes, with reference to (a) through (e) of FIG. 19, a process for fabricating the substrate 20. (a) through (e) of FIG. 19 are cross-sectional views showing steps of a process for fabricating the substrate 20, with the steps arranged in process sequence. (a) through (e) of FIG. 19 each correspond to a cross-section as taken along the line Y1-Y1 in FIG. 4.
First, the process (i) forms, on the insulating substrate 21 by sputtering, a film made of a transparent conductive material or a conductive material such as a metal material (for example, graphene or carbon) that is transparent in the form of a thin film, then (ii) forms a layer of photoresist (not illustrated), and (iii) carries out patterning with respect to the film by, for example, photolithography. This step forms, on the insulating substrate 21, electrodes 32 and 33 and connecting wires 36 (see FIGS. 3 and 4) as shown in (a) of FIG. 19.
Examples of the insulating substrates 11 and 21 include a glass substrate and a plastic substrate.
Examples of the transparent conductive material include ITO, IZO, zinc oxide, and tin oxide as mentioned above.
The respective thicknesses and electrode areas of the electrodes 32 and 33 may be determined as appropriate depending on the respective electrode materials used, and are therefore not particularly limited. In a case where the electrodes 32 and 33 are made of a transparent conductive material, the respective thicknesses and electrode areas of the electrodes 32 and 33 can be selected as have conventionally been done, for example.
In a case where the electrodes 32 and 33 are made of a conductive material such as a metal material (for example, graphene or carbon) that is transparent in the form of a thin film, the respective thicknesses of the electrodes 32 and 33 are selected so that the electrodes 32 and 33 are transparent. This ensures the optical transmittance of the electrodes 32 and 33 and the area of transparent regions of the electrodes 32 and 33.
Next, an insulating layer 34 is formed by, for example, chemical vapor deposition (CVD) or spin coating so as to entirely cover the plane of the insulating substrate 21 (on which components such as the electrodes 32 and 33 are formed) in which plane the electrodes 32 and 33 are formed. Then, a layer of photoresist (not illustrated) is formed on the insulating layer 34, and patterning is carried out with respect to the layer of photoresist by, for example, photolithography so that as shown in (b) of FIG. 19, openings 34a are formed in the insulating layer 34 to serve as contact holes.
Examples of the material for the insulating layer 34 include (i) organic insulating materials (photosensitive resins) such as acrylic resin, epoxy resin, polyurethane resin, and polyimide resin, and (ii) insulating, transparent inorganic insulating materials such as a SiNx film (silicon nitride film). Among others, the material for the insulating layer 34 is preferably a resin, such as a photosensitive resin, which includes an organic insulating material. The insulating layer 34 is therefore preferably an organic insulating layer including a so-called organic insulating film.
An organic insulating film can be thicker than an inorganic insulating film, and is lower in relative permittivity than an inorganic insulating film. Silicon nitride, for example, has a relative permittivity ∈ of 6.9, whereas acrylic resin has a relative permittivity ∈ of 3.7. Further, an organic insulating film is so high in transparency that it can be made thick.
Therefore, in a case where the insulating layer 34 is an organic insulating layer, it can be thick and is low in relative permittivity. Both of these characteristics allow the parasitic capacitance between the sensor electrode 31 and the counter electrode 27 to be reduced.
If the insulating layer 34 is excessively thin, there will be an increase in parasitic capacitance between the sensor electrode 31 and the counter electrode 27. If the insulating layer 34 is excessively thick, it will be difficult to form the contact holes 37 and 38. It is therefore preferable that the insulating layer 34 have a thickness within a range of 1 μm to 3.5 μm.
Next, on the insulating layer 34 in which the openings 34a have been formed to serve as contact holes, metal wires made of metal materials such as (i) low-resistance metals (for example, titanium (Ti), copper (Cu), gold (Au), aluminum (Al), tungsten (W), zinc (Zn), nickel (Ni), tin (Sn), chromium (Cr), molybdenum (Mo), and tantalum (Ta)) and (ii) metal compounds and metal silicides thereof are formed. During this step, the metal wires made of the metal materials are formed inside the openings 34a as well so that a metal bridge 35 made of the metal wires and contact holes 37 and 38 are formed as shown in (d) of FIG. 19.
After that, patterning is carried out with respect to the metal bridge 35 by, for example, photolithography so that disconnecting lines 39 are formed across the metal bridge 35 as shown in FIGS. 3 and 4. For lower resistance, it is desirable that the metal bridge 35 have a thickness of 100 nm or larger for low resistance, and for securement of the flatness of the counter electrode 27 and a reduction in processing costs, it is desirable that the metal bridge 35 have a thickness of 300 nm or smaller.
The method for forming disconnecting lines 39 across the metal bridge 35 is not limited to patterning that involves photolithography or the like. The method is not particularly limited as long as the metal bridge 35 can be partially disconnected (electrically separated).
Next, an insulating layer 25 is formed as shown in (d) of FIG. 19 to entirely cover the plane of the insulating substrate 21 (on which the metal bridge 35 is formed) in which plane those electrodes 32 and 33 are formed.
The material for the insulating layer 25 and the method for forming the insulating layer 25 can be, for example, similar to the material for the insulating layer 34 and the method for forming the insulating layer 34, respectively.
As with the insulating layer 34, in a case where the insulating layer 25 includes an organic insulating layer, it can be thick and is low in relative permittivity. Both of these characteristics allow the parasitic capacitance between the sensor electrode 31 and the counter electrode 27 to be reduced.
As with the insulating layer 34, if the insulating layer 25 is excessively thin, there will be an increase in parasitic capacitance between the sensor electrode 31 and the counter electrode 27. If the insulating layer 25 is excessively thick, it will be difficult, in a case where contact holes are formed in the insulating layer 25 as described in an embodiment below, to form such contact holes. It is therefore preferable that the insulating layer 25 have a thickness in a range of 1 μm to 3.5 μm, as with the insulating layer 34.
Next, on the insulating layer 25 as shown in (d) of FIG. 19, a CF layer 26 having a plurality of colors such as red (R), green (G), and blue (B) is formed by patterning that involves photolithography or by a known method such as an ink-jet printing method and a laminating method.
After that, a transparent conductive film including a transparent conductive material such as ITO, IZO, zinc oxide, and tin oxide on the CF layer 26 as shown in (e) of FIG. 19 by sputtering or the like to provide a counter electrode 27.
Finally, an alignment film (not illustrated) is formed on the counter electrode 27 as needed. This is how a substrate 20 can be produced.
The respective thicknesses, for example, of the CF layer 26, the counter electrode 27, and the alignment film are not particularly limited, and can therefore be selected as have conventionally been done.
<Process for Joining the Substrates on Top of Each Other>
The following describes a process for joining the substrates 10 and 20 on top of each other (that is, a process for assembling the liquid crystal panel 2).
First, a seal material 60 (see FIG. 1) in a frame pattern having a liquid crystal injection inlet is applied to one of the substrates 10 and 20 by screen printing or the like or by use of a dispenser or the like, and then spherical spacers which are made of plastic, silicon dioxide, or the like and which have a diameter equivalent to the thickness of a liquid crystal layer 50 are dispersed onto the other one of the substrates 10 and 20. Instead of the spacers being dispersed, spacers may be formed on the counter electrode 27 of the substrate 20 or on metallic wires of the substrate 10.
Next, the substrates 10 and 20 are joined on top of each other. After the seal material 60 has been cured, a liquid crystal material is injected, for example, by a vacuum injection method into a space defined by the substrates 10 and 20 and the seal material 60. After that, a UV cure resin is applied to the liquid crystal injection inlet, and the UV cure resin is irradiated with UV radiation to seal in the liquid crystal material, whereby a liquid crystal layer 50 is formed.
Alternatively, onto the substrate to which the seal material 60 has been applied in a frame pattern, a liquid crystal material is dropped by a drop method so that a space defined by the seal material 60 is filled with the liquid crystal material, and then the substrates 10 and 20 are joined on top of each other, whereby a liquid crystal layer 50 is formed between the substrates 10 and 20.
Usable examples of the seal material 60 include: an ultraviolet curing or thermosetting resin containing electrically conductive particles, a black pigment and the like (not illustrated); and an ultraviolet curing and thermosetting resin. Usable examples of the electrically conductive particles include gold beads.
This is how a liquid crystal panel 2 according to the present embodiment can be produced.
<Modifications>
The following describes modifications of individual constituent elements of the electro-optic device according to the present embodiment.
<Direction of Connection by Connecting Wires 36>
The present embodiment has been described by taking, as an example, a case where, as shown in FIGS. 3 and 4, electrodes 33 arranged along the X-axis are connected to each other via connecting wires 36 formed on the same level as the electrodes 33.
The present embodiment is, however, not limited to such an example, and may be configured such that (i) electrodes 32 arranged along the Y-axis are connected to each other via connecting wires 36 formed on the same level as the electrodes 32 and that (ii) electrodes 33 arranged along the X-axis are in an isolated pattern.
Therefore, either the electrodes 32 or the electrodes 33 may be in an isolated pattern. However, in a case where either the electrodes 32 or the electrodes 33 are connected to each other via transparent connecting wires 36, those electrodes that are arranged along a long side of the insulating substrate 21 are preferably in an isolated pattern. This configuration can reduce a conductive area where electricity travels only through the transparent connecting wires 36, and can also reduce the resistance of the sensor electrode 31, thus making it possible to reduce the CR time constant.
<Insulating Layer 34>
The present embodiment is configured such that on the electrodes 32 and 33, the insulating film 34 is provided in a solid state all over a surface of the insulating substrate 21 over which the touch panel layer 23 is stacked, in such a way as to entirely cover these electrodes 32 and 33.
However, the present embodiment is not limited to such a configuration. The insulating layer 34 needs only to be provided so as to prevent the electrodes 32 and the electrodes 33 from being electrically connected to each other via the metal bridge 35. Therefore, the insulating layer 34 needs only to be formed at least between (i) the metal bridge 35 and (ii) the electrodes 32 and 33 and the connecting wires 36 (that is, at least in a region in plan view where the metal bridge 35 is provided).
<Shape of Electrode Pattern>
The present embodiment is an example case where in the plane in which the electrodes 32 and 33 are formed, (i) either the electrodes 32 or the electrodes 33 are in an isolated pattern and (ii) the other electrodes are connected to each other via the connecting wires 36.
It is, however, at least either the electrodes 32 or the electrodes 33 that need to be in such a pattern as to be isolated from each other along a direction intersecting the direction along which the other electrodes are arranged. Thus, it may be both the electrodes 32 and the electrodes 33 that are in an isolated pattern.
In a case where at least either the electrodes 32 or the electrodes 33 are in an isolated pattern in the plane in which the electrodes 32 and 33 are formed, a metal bridge can connect the electrodes 32 or electrodes 33 to each other so that the electrodes 32 and 33 are not in contact with each other and not electrically connected to each other.
That is, the present embodiment needs only to be configured such that at least either the electrodes 32 or the electrodes 33 are bridge-connected to each other via a metal bridge so provided across those electrodes along a direction intersecting the direction along which the other electrodes are arranged. This makes it possible to connect the electrodes 32 or electrodes 33 to each other so that the electrodes 32 and 33 are not electrically connected to each other.
In a case where in the plane in which the electrodes 32 and 33 are formed, (i) at least either the electrodes 32 or the electrodes 33 are connected to each other via connecting wires, (ii) the other electrodes are in such a pattern as to be isolated from each other in a direction intersecting the direction along which the first group are arranged, and (iii) a metal bridge is formed at least along the direction along which the isolated pattern is provided, it is possible to connect the electrodes 32 or electrodes 33 to each other so that the electrodes 32 and 33 are not electrically connected to each other, and to simply and easily connect the electrodes 32 to each other or the electrodes 33 to each other.
<Connection by the Metal Bridge 35>
The present embodiment has been described by taking, as an example, a case where as shown in FIGS. 3 and 4, a disconnecting line 39 is formed, in plan view, between (i) each of the electrodes 32, which are arranged along the Y-axis, and (ii) an electrode 33 adjacent thereto along the X-axis, the disconnecting line 39 extending along the pattern of these electrodes 32 and 33.
However, the disconnecting lines 39 need only to electrically disconnect the electrodes 32 and the electrodes 33 from each other so that no electricity travels between the electrodes 32 and the electrodes 33.
Therefore, the disconnecting lines 39 do not necessarily need to be formed between the respective patterns of the electrodes 32 and the electrodes 33. The disconnecting lines 39 need only to be formed, in plan view, between the contact holes 37 and the contact holes 38 provided respectively for the electrodes 32 and the electrodes 33.
The present embodiment has been described by taking, as an example, a case where the electrodes 32 and the electrodes 33 are both electrically connected to the metal bridge 35 as shown in FIG. 3, FIG. 4, and (a) and (b) of FIG. 5.
However, the present embodiment may be configured such that of the electrodes 32 and the electrodes 33, only one group of electrodes that are not connected to each other via the connecting wires 36 (the electrodes 33 in the example shown in FIGS. 3 and 4) are electrically connected to a metal bridge 35 including a metal mesh.
In this case, with the insulating layer 34 provided between the metal bridge 35 and the other group of electrodes, the disconnecting lines 39 do not necessarily need to be provided between the electrodes 32 and the electrodes 33. For example, it is possible to electrically disconnect, for example, electrodes 32 from each other that are adjacent to each other along the X-axis with an electrode 33 therebetween.
Further, in this case, the disconnecting lines 39 need only to be formed, in plan view, between contact holes 37 formed in respective electrodes 32 adjacent to each other along the X-axis with an electrode 33 therebetween.
<Disconnecting Lines 39>
The present embodiment has been described by taking, as an example, a case where a single disconnecting line 39 is formed between electrodes 32 and 33 adjacent to each other. However, the present embodiment needs only to have at least one disconnecting line 39 formed between electrodes 32 and 33 adjacent to each other, and may therefore have two or more disconnecting lines 39 formed therebetween.
<Electro-Optic Device>
The present embodiment has been described by taking, as an example, a case where a liquid crystal layer 30 serving an electro-optic element (optically-modulated layer) is sandwiched between a pair of substrates 10 and 20. However, the present embodiment is not limited to such an example. The electro-optic element may alternatively be, for example, a dielectric liquid or organic EL (electroluminescent) layer.
The display panel and display device according to the present embodiment are not limited to a liquid crystal panel and liquid crystal display device, and may therefore be, for example, (i) an organic EL display panel and organic EL display device, or (ii) an electrophoretic display panel and electrophoretic display device.
In a case where the liquid crystal panel 2 is replaced with a self-luminous display panel such as an organic EL display panel, the present embodiment, needless to say, does not need an illumination device such as the backlight 3.
The present embodiment has been described by taking, as an example, a case where, as described above, the touch panel substrate is a substrate that is used in a display panel and the electro-optic device is a display device.
However, the touch panel substrate can be applied in general to any electro-optic device that has an electro-optic element driving electrode and a position detecting electrode. For example, the electro-optic device may for example be a viewing angle control panel placed on a display panel or the like in an overlapping manner.
The present embodiment has been described by taking, as an example, a case where the substrate 10, which serves as a counter substrate, is a CF substrate. However, the present embodiment is not to be limited to such an example, and may alternatively have a CF substrate provided on the array substrate side.
Embodiment 2
Another embodiment of the present invention is described below with reference to FIGS. 20 through 22. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiment 1 are each assigned an identical reference sign, and as such, are not described here.
FIG. 20 is a plan view showing a configuration of a main part of a touch panel layer 23 of a substrate 20 according to the present embodiment. (a) of FIG. 21 is a diagram showing a cross-section of the substrate 20 as taken along the line Y2-Y2 across the touch panel layer 23 shown in FIG. 20. (b) of FIG. 21 is a diagram showing a cross-section of the substrate 20 as taken along the line X3-X3 across the touch panel layer 23 shown in FIG. 20.
Further, FIG. 22 is a plan view schematically showing a configuration of a metal bridge 35 shown in FIG. 20.
Embodiment 1 is configured such that in a case where the electrodes 32 and 33 are electrically connected to the metal bridge 35, each region of the metal bridge 35 which region is between electrodes 32 and 33 adjacent to each other is disconnected at one place.
The present embodiment is, in contrast, configured such that each region of the metal bridge 35 which region is between electrodes 32 and 33 adjacent to each other is disconnected at two places as shown in FIGS. 20 and 22.
For this purpose, the present embodiment has two disconnecting lines 39 extending across the metal bridge 35 between (i) each of the electrodes 32, which are arranged along the Y-axis, and (ii) an electrode 33 adjacent to that electrode 32 along the X-axis.
For this reason, the present embodiment has metal wiring parts 35c which are electrically connected to neither of the electrodes 32 and 33 due to the disconnecting lines 39, which are each electrically in the form of a floating island, and which extend across the metal bridge 35 between (i) each of the electrodes 32, which are arranged along the Y-axis, and (ii) an electrode 33 adjacent thereto along the X-axis.
With this configuration, the metal bridge 35 includes (i) metal wiring parts 35a electrically connected to the respective electrodes 32, (ii) metal wiring parts 35b electrically connected to the respective electrodes 33, and (iii) metal wiring parts 35c that are each electrically in the form of a floating island.
Moreover, a metal wiring part 35c is provided at least between a metal wiring part 35a and a metal wiring part 35b. 
For this reason, the present embodiment makes it possible to reliably prevent a short circuit between a metal wiring part 35a and a metal wiring part 35b, thus making it possible to suppress a reduction in yield due to such a short circuit.
Such provision of a metal wiring part 35c between a metal wiring part 35a and a metal wiring part 35b makes it possible to reduce a capacitance (cross capacitance) which is formed between electrodes 32 and 33 and which does not vary depending on whether or not an object to be detected is in contact.
This makes it possible to reduce the CR time constant, thus making it possible to further facilitate a position detecting operation by as a touch panel.
<Modifications>
The following describes modifications of individual constituent elements of the electro-optic device according to the present embodiment.
<Connection by the Metal Bridge 35>
The present embodiment has been described by taking, as an example, a case where as shown in FIGS. 20 and 22, a disconnecting line 39 is formed, in plan view, between, (i) each of the electrodes 32, which are arranged along the Y-axis, and (ii) an electrode 33 adjacent thereto along the X-axis, the disconnecting line 39 extending along the pattern of these electrodes 32 and 33.
However, the disconnecting lines 39 need only to electrically disconnect the electrodes 32 and the electrodes 33 from each other so that no electricity travels between the electrodes 32 and the electrodes 33.
Therefore, the disconnecting lines 39 do not necessarily need to be formed between the respective patterns of the electrodes 32 and the electrodes 33. The disconnecting lines 39 need only to be formed, in plan view, between the contact holes 37 and the contact holes 38 provided respectively for the electrodes 32 and the electrodes 33.
The present embodiment has been described by taking, as an example, a case where the electrodes 32 and the electrodes 33 are both electrically connected to the metal bridge 35.
However, the present embodiment may be configured such that of the electrodes 32 and the electrodes 33, only one group of electrodes that are not connected to each other via the connecting wires 36 (the electrodes 33 in the example shown in FIG. 20) are electrically connected to a metal bridge 35 including a metal mesh.
In this case, with the insulating layer 34 provided between the metal bridge 35 and the other group of electrodes, the disconnecting lines 39 do not necessarily need to be provided between the electrodes 32 and the electrodes 33.
In a case, for example, of two disconnecting lines 39 provided between electrodes 32 adjacent to each other along the X-axis with an electrode 33 therebetween, it is possible to electrically disconnect such electrodes 32 from each other that are adjacent to each other along the X-axis with an electrode 33 therebetween and form a metal wiring part 35c that is electrically in the form of a floating island between columns of electrodes 32 adjacent to each other along the X-axis with an electrode 33 therebetween (i.e., between metal wiring parts 35a adjacent to each other).
In the above case, disconnecting lines 39 may simply be formed, in plan view, between contact holes 37 formed in respective electrodes 32 adjacent to each other along the X-axis with an electrode 33 therebetween.
Further, in this case, disconnecting lines 39 may simply be formed, in plan view, between contact holes 37 formed in respective electrodes 32 adjacent to each other along the X-axis with an electrode 33 therebetween.
Embodiment 3
Still another embodiment of the present invention is described below with reference to FIGS. 23 through 28. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiment 1 are each assigned an identical reference sign, and as such, are not described here.
FIG. 23 is a plan view showing a configuration of a main part of a touch panel layer 23 of a substrate 20 according to the present embodiment. FIG. 24 is a diagram showing a cross-section of the substrate 20 as taken along the line X4-X4 across the touch panel layer 23 shown in FIG. 23.
Further, FIG. 25 is a plan view schematically showing a configuration of a metal bridge 35 shown in FIG. 23.
Embodiment 2 is configured such that by forming two disconnecting lines 39 across the metal bridge 35 between (i) each of the electrodes 32, which are arranged along the Y-axis, and (ii) an electrode 33 adjacent thereto along the X-axis, a metal wiring part 35c that is electrically in the form of a floating island is formed in the metal bridge 35 between a metal wiring part 35a and a metal wiring part 35b. 
In contrast, the present embodiment, as shown in FIGS. 23 and 25, includes a disconnecting line 39 formed between a contact hole 37 provided for an electrode 32 and a contact hole 38 provided for an electrode 33, the disconnecting line 39 extending along the direction along which the electrodes 32 and 33 are arranged and intersecting the electrodes 32 and 33.
The example shown in FIGS. 23 and 25 includes disconnecting lines 39 formed so that contact holes 37 provided for respective electrodes 32 are interposed therebetween and the disconnecting lines 39 extend along the Y-axis, that is, along a central trunk line 35A that connects electrodes 32 to each other that are arranged along the Y-axis. The example further includes disconnecting lines 39 formed so that contact holes 38 provided for respective electrodes 33 are interposed therebetween and the disconnecting lines 39 extend along the X-axis.
With this configuration, the metal bridge 35 is provided with metal wiring parts 35c which are provided between the metal wiring parts 35a electrically connected to the respective electrodes 32 and the metal wiring parts 35b electrically connected to the respective electrodes 33 and which are electrically connected to neither of the electrodes 32 and 33.
The resin layer 24 (that is, the insulating layer 25 and the CF layer 26) provided on the metal wiring parts 35c of the metal bridge 35 has, as shown in FIGS. 23 and 24, contact holes 28 via which the metal wiring parts 35c of the metal bridge 35 and the counter electrode 27 are electrically connected to each other.
The resin layer 24 has at least one contact hole 28 (two in the example shown in FIG. 23) for each metal wiring part 35c. 
Since those metal wiring parts 35c of the metal bridge 35 which are electrically connected to neither of the electrodes 32 and 33 are thus electrically connected to the counter electrode 27, the present embodiment makes it possible to reduce the resistance of the counter electrode 27. This makes it possible to reduce the CR time constant. Further, mounting the substrate 20 in the liquid crystal panel 2 makes it possible to reduce the resistance of the counter electrode 27, thus making it possible to reduce the CR time constant and thereby increasing the SN ratio.
<Process for Fabricating a Substrate 20>
The following describes only differences in process between the present embodiment and Embodiment 1.
In the present embodiment, disconnecting lines 39 are formed across the metal bridge 35 as shown in FIGS. 23 and 25 instead of disconnecting lines 39 being formed as shown in (c) of FIG. 19 for Embodiment 1.
Next, an insulating layer 25 and a CF layer 26 are formed on the metal bridge 35 as shown in (d) of FIG. 19, and then patterning is carried out with respect to these insulating layer 25 and CF layer 26 by, for example, photolithography with use of a photoresist (not illustrated). This causes opening to be formed in the insulating layer 25 and the CF layer 26 as shown in FIG. 24 to serve as contact holes 28.
Next, during a step corresponding to the step shown in (e) of FIG. 19, a transparent conductive film is formed inside the openings as well that are formed in the insulating layer 25 and the CF layer 26, whereby a counter electrode 27 and contact holes 28 are formed.
The other steps are identical to their respective corresponding steps described in Embodiment 1. The above process allows production of the substrate 20 according to the present embodiment and a liquid crystal panel 2 including the substrate 20.
<Modifications>
The following describes modifications of individual constituent elements of the electro-optic device according to the present embodiment.
FIG. 26 is a plan view showing a configuration of a main part of a touch panel layer 23 of another substrate 20 according to the present embodiment. (a) of FIG. 27 is a diagram showing a cross-section of the substrate 20 as taken along the line Y3-Y3 across the touch panel layer 23 shown in FIG. 26. (b) of FIG. 27 is a diagram showing a cross-section of the substrate 20 as taken along the line X5-X5 across the touch panel layer 23 shown in FIG. 26. (c) of FIG. 27 is a diagram showing a cross-section of the substrate 20 as taken along the line X6-X6 across the touch panel layer 23 shown in FIG. 26.
FIG. 28 is a plan view schematically showing a configuration of a metal bridge 35 shown in FIG. 26.
The example shown in FIG. 23 includes a single contact hole 37 at the center of an electrode 32, the contact hole 37 having a size substantially equal to the width of a connecting wire 36. This example thus forms rectangular electrode wiring parts 35a, 35b, and 35c in the metal bridge 35 by forming disconnecting lines 39 extending (i) along the Y-axis so that contact holes 37 formed in respective electrodes 32 are interposed therebetween and (ii) through a region between contact holes 38 formed in respective electrodes adjacent to each other along the X-axis.
The example shown in FIG. 26, in contrast, includes two contact holes 37 along X-axis for each electrode 32 to form electrode wiring parts 35a, 35b, and 35c that are shaped as shown in FIG. 28.
The respective shapes and sizes of the electrode wiring parts 35a, 35b, and 35c may be selected as appropriate depending, as described above, on the respective sizes and numbers of the contact holes 37 and 38 formed respectively for the electrodes 32 and 33.
The present embodiment, as shown in FIGS. 23 through 28, includes disconnecting lines 39 formed to enclose, in plan view, connection parts at each of which electrodes 32 and 33 are connected to the metal bridge 35 via contact holes 37 and 38 (specifically, such connection parts correspond to (i) a region of each electrode 32 which region is between contact holes 37 and (ii) a region of each electrode 33 which region is between contact holes 38).
The present embodiment can thus secure a large area for the metal wiring parts 35c (that is, an area of the metal bridge 35 by which area it is connected to the counter electrode 27) in comparison to a case where a disconnecting line 39 is formed across the metal bridge 35 between (i) each of the electrodes 32, which are arranged along the Y-axis, and (ii) an electrode 33 adjacent thereto along the X-axis, the disconnecting line 39 extending along the pattern of the electrodes 32 and 33. The present embodiment can consequently reduce the resistance of the counter electrode 27.
Further, the present embodiment, which electrically disconnects the metal bridge 35 with use of the disconnecting lines 39, can form metal wiring parts insulated from the electrodes 32 and 33 without forming a separate metal layer. In other words, the present embodiment can form metal wiring parts insulated from the electrodes 32 and 33 without increasing the number of components or the thickness of the substrate 20.
Embodiment 4
Still another embodiment of the present invention is described below with reference to FIGS. 29 through 36. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiments 1 through 3 are each assigned an identical reference sign, and as such, are not described here.
The following takes contact holes 37 as an example for the present embodiment to describe a modification of contact holes 37 for connecting the sensor electrode 31 and the metal bridge 35 to each other.
<Number of Contact Holes>
FIG. 29 is a plan view showing a configuration of a main part of a touch panel layer 23 of a substrate 20 according to the present embodiment. (a) of FIG. 30 is a diagram showing a cross-section of the substrate 20 as taken along the line Y4-Y4 across the touch panel layer 23 shown in FIG. 29. (b) of FIG. 30 is a diagram showing a cross-section of the substrate 20 as taken along the line X7-X7 across the touch panel layer 23 shown in FIG. 29.
FIGS. 3 and 4 and FIGS. 20 and 23 for Embodiments 1 and 2 have been illustrated by taking, as an example, a case where the electrodes 32 each have a single contact hole 37, for example, at its center and are electrically connected to the metal bridge 35 via the contact holes 37.
There are, however, preferably a plurality of contact holes 37 for each electrode as shown, for example, in FIG. 29.
Electrodes 32 arranged along the Y-axis are bridge-connected to each other via the metal bridge 35. Thus, providing each electrode 32 with a plurality of contact holes 37 via which the electrode 32 is connected to the metal bridge 35 makes it possible to ensure an electric connection between the electrodes 32 even in a case where there has occurred a faulty connection such as a disconnection at a contact hole 37. This makes it possible to improve yields.
Further, not only those electrodes 32 connected to each other via the metal bridge 35, but also (i) each electrode 32 for use in the sensor electrode 31 is preferably provided with a plurality of contact holes 37 via which it is connected to the metal bridge 35 and (ii) each electrode 33 for use in the sensor electrode 31 is preferably provided with a plurality of contact holes 38 via which it is connected to the metal bridge 35.
This makes it possible to ensure the area of connection parts between the metal bridge 35 and the electrodes 32 and 33, and reduce the respective resistances of the electrodes 32 and 33.
<Arrangement of Contact Holes for Use in Interelectrode Connection>
FIG. 31 is a plan view showing a configuration of a main part of a touch panel layer 23 of another substrate 20 according to the present embodiment. FIG. 31 is illustrated by taking, as an example, a case where a single disconnecting line 39 is provided across the metal bridge 35 between (i) each of the electrodes 32, which are arranged along the Y-axis, and (ii) an electrode 33 adjacent thereto along the X-axis.
Meanwhile, FIG. 32 is a plan view showing a configuration of a main part of a touch panel layer 23 having two disconnecting lines 39 provided between each of the electrodes 32 which are arranged along the Y-axis on the metal bridge 35 and an electrode 33 adjacent to that electrode 32 along the X-axis.
(a) of FIG. 33 is a diagram showing a cross-section of the substrate 20 as taken along the line Y5-Y5 across the touch panel layer 23 shown in FIG. 32. (b) of FIG. 33 is a diagram showing a cross-section of the substrate 20 as taken along the line X8-X8 across the touch panel layer 23 shown in FIG. 32. (c) of FIG. 33 is a diagram showing a cross-section of the substrate 20 as taken along the line X9-X9 across the touch panel layer 23 shown in FIG. 32.
FIGS. 3 and 4, FIGS. 20 and 23, and FIG. 29 have been illustrated by taking, as an example, a case where contact holes 37 are, regardless of the number thereof, provided in a central trunk line 35A of the metal bridge 35 (see FIGS. 31 and 32; the wires each marked by a chain double-dashed line in FIG. 31), the central trunk line 35A extending on a diagonal of each electrode 32 along the Y-axis.
The example shown in FIGS. 31 and 32 includes contact holes 37 formed, not in a central trunk line 35A of the metal bridge 35 for electrodes 32, but in branch line parts 35B intersecting the central trunk line 35A.
Forming contact holes 37 in not the central trunk lines 35A but the branch line parts 35B as described above makes it possible to prevent a disconnection, and thus making it possible to improve yields.
FIGS. 31 and 32 are illustrated by taking, as an example, a case where (i) electrodes 32 arranged along the Y-axis are electrically connected to each other via a central trunk line 35A of the metal bridge 35 and (ii) wires of the metal bridge 35 which extend along the Y-axis and which are other than the central trunk lines 35A are disconnected between electrodes 32 arranged along the Y-axis.
However, the disconnecting lines 39 do not necessarily need to be formed between the respective patterns of the electrodes 32 and the electrodes 33. The disconnecting lines 39 need only to be formed, in plan view, between the contact holes 37 and the contact holes 38 provided respectively for the electrodes 32 and the electrodes 33 as described in Embodiment 2. Therefore, electrodes 32 arranged along the Y-axis may be connected to each other via wires (trunk lines) which extend along the Y-axis and which are other than the central trunk lines 35A.
Thus, the contact holes 37 are not limitedly provided in the branch line parts 35B intersecting the central trunk lines 35A. The contact holes 37 are preferably formed in branch line parts intersecting trunk lines of the metal bridge 35 which trunk lines connect electrodes (electrodes 32 in the present embodiment) connected to each other via the metal bridge 35. This makes it possible to prevent a disconnection, thus making it possible to improve yields.
<Arrangement of Contact Holes for Use in Connection Between Electrodes Connected to Each Other Via Connecting Wires>
FIG. 34 is a plan view showing a configuration of a main part of a touch panel layer 23 of still another substrate 20 according to the present embodiment. FIG. 35 is a plan view showing a configuration of (i) an intersection between a column of electrodes 32 and a row of electrodes 33 on the touch panel layer 23 shown in FIG. 34 and (ii) an area around the intersection. FIG. 35 is an enlarged view of a region 81 enclosed by a thick line in FIG. 34.
In FIGS. 34 and 35, either (i) the electrodes 32 arranged along a first direction or (ii) the electrodes 33 arranged along a second direction intersecting the first direction are not in an isolated pattern, but are connected to each other via transparent connecting wires 36.
The following describes, as an example, a case where, of the electrodes 32 and the electrodes 33, the electrodes 33 are connected to each other via transparent connecting wires 36.
In this case, each of the electrodes 33 connected to each other via the transparent connecting wires 36 is preferably provided with a contact hole 38 in the vicinity of an intersection between a column and row of electrodes (that is, at an edge of each of the electrodes 33 connected to each other via the transparent connecting wire 36) as shown in FIGS. 34 and 35.
In this case, a conductive area where electricity travels only through the transparent connecting wires 36 can be made smaller. This configuration makes it possible to reduce the resistance of each of the electrodes 33 connected to each other via the transparent connecting wires 36, thus making it possible to reduce the CR time constant.
<Shapes and Areas of Contact Holes>
FIG. 36 is a plan view collectively showing modifications of contact holes in the touch panel layer 23 of the substrate 20 according to the present embodiment. FIG. 36 illustrates contact holes 37 as examples.
It is preferable that the area over which a contact hole 37 is formed for a single electrode 32 be large enough to ensure the area of a connection part between the metal bridge 35 and the electrode 32.
FIG. 36 illustrates, in a region 82 enclosed with a chain double-dashed line, an example in which a plurality of contact holes 37 are provided around each corner of electrodes 32 along the Y-axis in correspondence with each wire intersection (grid portion) of a mesh metal constituting the metal bridge 35.
By thus increasing the number of contact holes 37, the area over which the contact holes 37 are formed can be sufficiently increased.
FIG. 36 illustrates, in a region 83 enclosed by a chain double-dashed line, an example in which an electrode 32 is provided with a horizontally long contact hole 37 which is long along the X-axis and which intersects the Y-axis, i.e. the direction of connection by the metal bridge 35.
FIG. 36 illustrates, in a region 84 enclosed by a chain double-dashed line, an example in which an electrode 32 is provided with a large contact hole 37 that covers a plurality of wire intersections (grid portions) of a mesh metal constituting the metal bridge 35.
The contact holes 37 in the regions 83 and 84 are horizontally long or large as described above, and are therefore so formed as to cover a plurality of wires extending next to the central trunk lines 35A of the metal bridge 35 (for example, in parallel to the central trunk lines 35A).
As described above, the metal bridge 35 is so formed as to serve also as a light blocking layer (BM), which covers the space between pixels.
The contact holes 37 in the regions 83 and 84 are therefore so formed as to cover a plurality of pixels.
The area over which the contact holes 37 are formed may be increased by thus increasing the size of contact holes 37 instead of increasing the number of contact holes 37.
Embodiment 5
Another embodiment of the present invention is described below with reference to (a) through (e) of FIG. 40. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiments 1 through 4 are each assigned an identical reference sign, and as such, are not described here.
Embodiments 1 through 4 have discussed by taking, as an example, the case in which the metal bridge 35 serves also as a BM (light blocking layer) and no BM is provided. The present embodiment is discussed by taking, as an example, a case in which the metal bridge 35 serves also as a BM (light blocking layer) and another light blocking layer is further provided in addition to the metal bridge 35.
Note that “the metal bridge 35 serves also as a light blocking layer” indicates that the metal bridge 35 serve also as a light blocking layer (BM) which is necessary when the substrate 20 is incorporated into the liquid crystal cell 4. Specifically, in a case where the substrate 20 is mounted in the liquid crystal panel 2, for example, the metal bridge 35 is formed, in a region in which a light blocking layer is to be formed, so that the metal bridge 35 serves also as a grid-shaped light blocking layer which is provided between pixels.
FIG. 37 is a cross-sectional view schematically showing a configuration of a main part of the substrate 20 according to the present embodiment, with the constituent layers stacked in the order shown.
As shown in FIG. 37, the substrate 20 according to the present embodiment includes an insulating substrate 21, a touch panel layer 23, an insulating layer 25, a light blocking layer 22 (BM), and a CF layer 26, and a counter electrode 27, which are stacked in this order.
Note that the touch panel layer 23 is configured as described above. The substrate 20 according to the present embodiment has a configuration substantially identical with that of the substrate 20 according to Embodiments 1 through 4 except that the light blocking layer 22 is provided in the substrate 20 according to the present embodiment.
The light blocking layer 22 overlaps the metal bridge 35 in plan view so as to cover the space between pixels.
In other words, the light blocking layer 22 covers the metal bridge 35 as seen in plan view. This allows the present embodiment to use the light blocking layer 22 to block light reaching the region where the metal bridge 35 is formed and to block light leaking laterally from the metal bridge 35 or light reflected by the metal bridge 35.
Further, since the light blocking layer 22 corresponds in shape to the metal bridge 35, the light blocking layer 22 and the metal bridge 35 can be formed with use of the same mask pattern. This allows a reduction in the number of masks and therefore a reduction in processing cost.
<Configuration Example 1 of the Substrate 20>
FIG. 38 is a set of cross-sectional views (a) and (b) each schematically showing a configuration of a substrate 20 in which a touch panel layer 23 shown in FIG. 4 is provided. Note that the configuration of the touch panel layer 23 and the metal bridge 35 is identical with that shown in FIGS. 4 and 6, and therefore a plan view of the touch panel layer 23 and the metal bridge 35 is not illustrated for this example.
(a) of FIG. 38 shows a cross-section of the substrate 20 as taken along the line Y1-Y1 across the touch panel layer 23 shown in FIG. 4. (b) of FIG. 38 shows a cross-section of the substrate 20 as taken along the line X2-X2 across the touch panel layer 23 shown in FIG. 4.
<Configuration Example 2 of the Substrate 20>
FIG. 39 is a set of cross-sectional views (a) and (b) each schematically showing a configuration of a substrate 20 in which a touch panel layer 23 shown in FIG. 20 is provided. Note that the configuration of the touch panel layer 23 and the metal bridge 35 is identical with that shown in FIGS. 20 and 22, and therefore a plan view of the touch panel layer 23 and the metal bridge 35 is not illustrated for this example.
(a) of FIG. 39 shows a cross-section of the substrate 20 as taken along the line Y2-Y2 across the touch panel layer 23 shown in FIG. 20. (b) of FIG. 39 shows a cross-section of the substrate 20 as taken along the line X3-X3 across the touch panel layer 23 shown in FIG. 20.
The light blocking layer 22 can be made of, for example, a known resin BM (i.e., a light blocking resin).
In a case where the metal bridge 35 serves also as the light blocking layer as above described, another light blocking layer does not necessarily need to be provided. Therefore, in a case where another light blocking layer is not provided as in, for example, Embodiment 1, it is possible to reduce the number of components and accordingly to reduce processing cost.
However, in a case where the metal bridge 35 is connected to the electrodes 32 and 33, the disconnecting lines 39 are provided in the metal bridge 35 so that no electricity travels between the electrodes 32 and 33. Under the circumstances, by providing the light blocking layer 22 in addition to the metal bridge 35, it is possible to prevent light from leaking from cross sections of the metal bridge 35, which is in the mesh pattern, or the like.
Note that the arrangement of the light blocking layer 22 shown in FIG. 37 through (a) and (b) of FIG. 39 is merely an example, and a location of the light blocking layer 22 is not limited to the location between the insulating layer 25 and the CF layer 26.
In a case where the light blocking layer 22 is provided between the insulating layer 25 and the CF layer 26 as shown in FIG. 37 through (a) and (b) of FIG. 39, it is easy to align the light blocking layer 22 with CF layers 26 of different colors when the light blocking layer 22 is formed so as to be positioned between the CF layers 26 of different colors.
Moreover, in this case, the light blocking layer 22 is provided between the metal bridge 35 and the counter electrode 27, and this makes it possible to distance the sensor electrode 31 from the counter electrode 27. This allows a reduction in parasitic capacitance between the sensor electrode 31 and the counter electrode 27.
<Process for Fabricating a Substrate 20>
The following description will discuss a process for fabricating the substrate 20 with reference to (a) through (e) of FIG. 40. Note that the cross section taken along the line Y1-Y1 of FIG. 4 across the substrate 20 shown in (a) and (b) of FIG. 38 is identical with the cross section taken along the line Y2-Y2 of FIG. 20 across the substrate 20 shown in (a) and (b) of FIG. 39. From this, the following collectively describes the process for fabricating the substrate 20 shown in (a) and (b) of FIG. 38 and (a) and (b) of FIG. 39.
FIG. 40 is a set of cross-sectional views (a) through (e) showing steps of a process for fabricating the substrate 20 with the steps arranged in process sequence, and corresponds to the Y1-Y1 cross section of FIG. 4 or the Y2-Y2 cross section of FIG. 20.
Note that the process shown in (a) through (c) of FIG. 40 are substantially identical with the process shown in (a) and (b) of FIG. 19 except that the number of disconnecting lines 39 is different between the substrate 20 shown in (a) and (b) of FIG. 38 and the substrate 20 shown in (a) and (b) of FIG. 39.
Therefore, descriptions of the steps shown in (a) through (c) of FIG. 40 are omitted here.
In the step shown in (d) of FIG. 40, an insulating layer 25 is formed so as to entirely cover a surface of the insulating substrate 21 on which surface the electrodes 32 and 33 and the metal bridge 35 have been formed, in a manner similar to that shown in (d) of FIG. 19.
Subsequently, a light blocking layer 22 (BM) is formed over the insulating substrate 21 by (i) forming a film from a light blocking material on the insulating layer 25 and then (ii) patterning the film.
Examples of the material for the light blocking layer 22 include a photosensitive resin having a black pigment or the like dispersed therein. The photosensitive resin can be a publicly known photosensitive resin such as an acrylic photosensitive resin.
The light blocking layer 22 can be formed by a well-known method. The light blocking layer 22 can be formed, for example, by (i) applying a photosensitive resin having a black pigment dispersed therein to an insulating layer 25 by spin coating, (ii) exposing, through a photolithographic mask, the photosensitive resin thus applied, and then (iii) developing the photosensitive resin.
The light blocking layer 22 may alternatively be formed by (i) forming, on a surface of an insulating layer 25, a laminate of dry films including a black resin film, (ii) removing a cover film for transfer of the black resin film, (iii) exposing the black resin film through a photolithographic mask, and then (iv) developing the black resin film.
During this step, the light blocking layer 22 is so patterned that when it is included in the liquid crystal panel 2, the light blocking layer 22 will cover switching elements and wires (for example, gate lines, source lines, and auxiliary capacitor lines) on the substrate 10, as with the metal bridge 35. Note that an identical photolithographic mask can be used as a pattern mask for the light blocking layer 22 and a pattern mask for the metal bridge 35.
The process next forms, in openings in the light blocking layer 22 as shown in (e) of FIG. 40, a CF layer 26 having a plurality of colors such as red (R), green (G), and blue (B) by patterning involving photolithography or by a known method such as ink-jet printing, laminating, and pigment dispersion.
The process then forms a counter electrode 27 as shown in (e) of FIG. 40, in a manner similar to that shown in (e) of FIG. 19.
The process finally forms an alignment film (not illustrated) on the counter electrode 27 as needed. This completes the production of the substrate 20 according to the present embodiment.
In the present embodiment also, the respective thicknesses of, for example, the light blocking layer 22, the CF layer 26, the counter electrode 27, and the alignment film are not particularly limited, and can thus be selected as conventional.
Embodiment 6
Another embodiment of the present invention is described below with reference to FIG. 41. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiments 1 through 5 are each assigned an identical reference sign, and as such, are not described here.
FIG. 41 is a plan view showing a configuration of a main part of a touch panel layer 23 included in a substrate 20 according to the present embodiment.
Embodiments 1 through 5 have each been described by taking, as an example, a case where the electrodes 32 and 33 are each (i) in a rectangular shape (for example, in a square shape) in plan view and (ii) so oriented as to have diagonals extending along the X-axis and the Y-axis.
The present embodiment is, in contrast, arranged as shown in FIG. 41 such that the electrodes 32 and 33 are each (i) in a rectangular pattern (an oblong shape in the example shown in FIG. 41) in plan view and (ii) so oriented as to have sides extending along the X-axis and the Y-axis.
The present embodiment, as well as the above embodiments, is configured such that electrodes 33 arranged along the X-axis are connected to each other via connecting wires 36 provided along the X-axis. In a case where the connecting wires 36 and the electrodes 33 are made of the same material, the electrodes 33 and the connecting wires 36 may be formed integrally on the same level.
In the example shown in FIG. 41, electrodes 33 arranged along the X-axis are connected to each other via connecting wires 36 at sides along the X-axis. Each row of electrodes 33 is thus formed in a comb shape.
On the other hand, electrodes 32 arranged along the Y-axis are each structured to include (i) two rectangular electrode parts 32a adjacent to each other along the X-axis and (ii) a connection part 32b provided along the X-axis via which the electrode parts 32a are connected to each other at sides along the X-axis.
As such, the electrodes 32 are so formed in a depressed shape as to engage with the comb-shaped pattern of the row of electrodes 33.
The electrodes 32 are each electrically connected, via contact holes 37 provided in its electrode parts 32a, to the metal bridge 35 constituted by a mesh metal.
The metal bridge 35 has a disconnection in the space between each of the electrodes 32 and an electrode 33 adjacent thereto, so that no electricity travels between the electrode 32 and the electrode 33.
As such, in the present embodiment, disconnecting lines 39 extending across the metal bridge 35 are so provided as to surround each electrode 33 in plan view.
This makes it possible to electrically connect the electrodes 32 and the metal bridge 35 to each other while preventing electricity from traveling between the electrodes 32 and the electrodes 33, thus making it possible to reduce the CR time constant.
Connecting only the electrodes 32 to the metal bridge 35 makes it possible to form, in each region surrounded by the disconnecting lines 39, a metal wiring part 35c that is electrically in the form of a floating island. The metal wiring part 35c in this case can be electrically connected to the counter electrode 27.
In contrast, forming, in the electrodes 33, contact holes 38 as indicated by chain double-dashed lines to connect the electrodes 33 and the metal bridge to each other makes it possible to form, in each region surrounded by the disconnecting lines 39, a metal wiring part 35b that is electrically connected to an electrode 33.
Embodiment 7
Another embodiment of the present invention is described below with reference to FIGS. 42 through 49. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiments 1 through 6 are each assigned an identical reference sign, and as such, are not described here.
<Configuration of the Substrate 20>
FIG. 42 is a plan view showing a configuration of a main part of a touch panel layer 23 included in a substrate 20 according to the present embodiment. (a) of FIG. 43 shows a cross-section of the substrate 20 as taken along the line Y6-Y6 across the touch panel layer 23 shown in FIG. 42. (b) of FIG. 43 shows a cross-section of the substrate 20 as taken along the line X10-X10 across the touch panel layer 23 shown in FIG. 42.
FIG. 44 is a plan view schematically showing a configuration of a metal bridge 35 shown in FIG. 42.
<Configuration of the Substrate 20>
According to Embodiments 1 through 6, the sensor electrode 31 includes, as an X electrode and a Y electrode, rectangular electrodes 32 and 33, respectively, which are formed on the same plane.
According to the present embodiment, as shown in FIG. 42, the sensor electrode 31 includes, instead of electrode 32 columns, a plurality of electrodes 132 (first electrodes) in the form of a sheet-shaped pattern (planar-shaped pattern) of quadrangular shapes (rectangular shapes) as seen in plan view, which electrodes 132 serve as Y electrodes each extending along a Y-axis.
As shown in FIG. 42, the plurality of electrodes 132, provided independently of one another, are arranged in the form of stripes running parallel to one another along an X-axis. Note that no X electrodes are provided. Drawing wires (not illustrated) are provided on the respective electrodes 132, and are connected, via a terminal area 40, to a position detecting circuit or the like.
According to the present embodiment, (i) one of any adjacent two of the electrodes 132 is used as a driving electrode (transmitting electrode) which constitutes a driving line and (ii) the other of the any adjacent two of the electrodes 132 is used as a detecting electrode (receiving electrodes) which constitutes a detecting line.
The electrodes 132 are transparent as with the electrodes 32 and 33. The electrodes 132 can be made of a material similar to a material of which the electrodes 32 and 33 are made.
According to the present embodiment, the electrodes 32 and 33 are thus transparent electrodes, each of which has a form of a sheet-shaped pattern. This allows each of the electrodes 132 to secure optical transmittance and an area of transparent region.
As shown in FIG. 42 and (a) and (b) of FIG. 43, the metal bridge 35 made up of a mesh metal is provided on the electrodes 132 via an insulating layer 34.
The insulating layer 34 has contact holes 137 via which the electrodes 132 and the metal bridge 35 are electrically connected to each other.
At least one contact hole 137 (two in the example shown in FIG. 42) is provided per electrode 132.
The metal bridge 35 has bridge connections with the electrodes 132 via the contact holes 137.
The electrodes 132, which are provided adjacently along the X-axis on the metal bridge 35, are disconnected from each other so that no electricity travels therebetween.
Disconnecting lines 39 are provided so as to extend along the electrodes 132 in respective spaces between the electrodes 132 which are adjacent to each other along the X-axis.
The disconnecting lines 39 cause the metal bridge 35 to be divided into a plurality of metal wiring parts 35d, which are electrically connected to the respective electrodes 132 which are adjacent to each other along the X-axis. The disconnecting lines 39 cause the electrodes 132, which are adjacent to each other along the X-axis, to be electrically insulated from one another.
According to the present embodiment also, the electrodes 132 are thus electrically connected, via the insulating layer 34, to the metal bridge 35 which is formed by the grid of metal wires. This allows a reduction in resistance of the sensor electrode 31 while the optical transmittance and the area of transparent region are ensured. Therefore, in a case where the substrate 20 is provided as a touch panel substrate on a liquid crystal panel 2, it is possible to reduce the resistance of the sensor electrode 31 while ensuring the aperture ratio of the liquid crystal panel 2.
In addition, since it is thus possible to reduce the resistance of the sensor electrode 31, it is also possible to reduce a CR time constant.
Therefore, with the present embodiment also, it is possible to provide a touch panel substrate and an electro-optic device, each of which is high in position detection performance and is therefore capable of carrying out a stable position detecting operation.
According to the present embodiment, (i) the plurality of electrodes 132, which are Y electrodes, are arranged along the X-axis and (ii) no X electrodes are provided. This results in detection of a position of an object to be detected which position is indicated by only coordinates of the X-axis direction.
<Process for Fabricating a Substrate 20>
The following description will discuss, with reference to (a) through (e) of FIG. 45, a process for fabricating the substrate 20.
(a) through (e) of FIG. 45 are cross-sectional views showing steps of a process for fabricating the substrate 20, and are each a view corresponding to the cross section taken along the line Y6-Y6 shown in FIG. 42.
First, as shown in (a) of FIG. 45, electrodes 132 in the form of stripes extending along a Y-axis are formed on an insulating substrate 21 as in the process shown in (a) of FIG. 19, except that a photolithographic mask is used which is different in mask pattern from the photolithographic mask used to form the electrodes 32 and 33 and the connecting wire 36 in Embodiment 1.
Next, as shown in (a) of FIG. 45, an insulating layer 34 is formed in a manner similar to that shown in (b) of FIG. 19. Then, as shown in (a) of FIG. 45, openings 34a, which are to serve as the contact holes 137 shown in FIG. 42, are formed in the insulating layer 34 for the respective electrodes 132 in a manner similar to that shown in (b) of FIG. 19.
Next, as shown in (c) of FIG. 45, a metal bridge 35 is formed on the insulating layer 34 and contact holes 137 are formed in the insulating layer 34 in a manner similar to that shown in (c) of FIG. 19. Then, the electrodes 132, which are provided adjacently along an X-axis, are electrically disconnected from one another in a manner similar to that shown in (c) of FIG. 19.
Thus, disconnecting lines 39 in the form of stripes are formed in respective spaces between the electrodes 132 which are adjacently arranged along the X-axis. This allows metal wiring parts 35d, which are electrically connected to the respective electrodes 132, to be formed in the metal bridge 35 without causing electrical conduction through the electrodes 132 which are adjacently arranged along the X-axis.
Next, in a manner similar to that shown in (d) of FIG. 19, an insulating layer 25 and a CF layer 26 are formed so as to cover the entire surface of the insulating substrate 21, on which surface the metal bridge 35 and the electrodes 132 are formed (see (d) of FIG. 45).
Then, in a manner similar to that shown in (e) of FIG. 19, a counter electrode 27 is formed (see (e) of FIG. 45).
Finally, an alignment film (not illustrated) is formed on the counter electrode 27 as needed, so that the substrate 20 according to the present embodiment is fabricated.
Note that, according to the present embodiment also, thicknesses of a light blocking layer 22, the CF layer 26, the counter electrode 27, the alignment film, and the like are not particularly limited, but can be set in a manner similar to a conventional technique.
<Modification>
The following description will discuss a modification of the constituent elements in the electro-optic device of the present embodiment.
<Connection by the Metal Bridge 35>
The present embodiment employs the example configuration in which, as shown in FIG. 42, the disconnecting lines 39 are formed between and along the respective electrodes 132 which are provided adjacently along the X-axis in the plan view.
However, it is only necessary for the disconnecting lines 39 to cause the electrodes 132 to be electrically disconnected so that no electricity travels between the electrodes 132 which are adjacent to each other along the X-axis.
Therefore, the disconnecting lines 39 do not necessarily need to be provided between the electrodes 132 which are adjacent to each other along the X-axis, but need only to be provided between the contact holes 137 which are provided on the respective electrodes 132 in the plan view.
<Alignment Direction of Electrodes 132>
The present embodiment also employs, as described above, the example configuration in which only Y electrodes are provided without providing any X electrodes. However, the present embodiment is not limited to such a configuration. For example, only X electrodes can be provided without providing Y electrodes.
In such a case, a plurality of electrodes 132 are configured to extend, instead of along the Y-axis, along the X-axis so as to be arranged along the Y-axis. This allows a detection of only a coordinate along the Y-axis of an object to be detected.
<Shape of Electrodes 132>
The present embodiment employs the example configuration in which the electrodes 132 in the form of stripes extending along the Y-axis are provided as Y electrodes (see FIG. 42). However, the present embodiment is not limited to such a configuration.
For example, instead of the electrodes 132 in the form of stripes, a configuration can be employed in which a plurality of rectangular-shaped (e.g. square-shaped) electrodes 32 each having diagonals along an X-axis and a Y-axis are arranged along the X-axis and the Y-axis as in Embodiment 1.
In such a case, the electrodes 32 can be arranged independently of one another along the X-axis and the Y-axis. Alternatively, the electrodes 32 can be connected to one another along the X-axis or the Y-axis via connecting wires 36. In such a case, as in Embodiment 1, a metal bridge 35 makes bridge connection between the electrodes 32 via contact holes 37 which are provided in the respective electrodes 32.
<Light Blocking Layer 22>
According to the present embodiment also, a light blocking layer 22 (BM) can be provided on the substrate 20 as in Embodiment 5.
<Example 1 of Arrangement of the Light Blocking Layer 22>
(a) and (b) of FIG. 46 are cross-sectional views schematically showing a main configuration of a substrate 20 in which a light blocking layer 22 is provided between an insulating layer 25 and a CF layer 26. Note that (a) of FIG. 46 corresponds to a cross section of the substrate 20 taken along the line Y6-Y6 shown in FIG. 42, and (b) of FIG. 46 corresponds to a cross section of the substrate 20 taken along the line X10-X10 shown in FIG. 42.
Note also that, since a touch panel layer 23 and a metal bridge 35 are configured in a manner identical with that shown in FIG. 42, a plan view of the touch panel layer 23 and the metal bridge 35 is omitted here.
The substrate 20 shown in (a) and (b) of FIG. 46 can be fabricated by, during the step shown in (d) of FIG. 45, carrying out the step shown (d) of FIG. 40, that is, (I) forming a light blocking layer 22 (BM) on an insulating layer 21 by forming, on an insulating layer 25, a film made of a material having a light blocking property, and then patterning the film and then (II) forming a CF layer 26.
According to the present embodiment also, as shown in (a) and (b) of FIG. 46, it is possible to distance a sensor electrode 31 (i.e. electrodes 132) from a counter electrode 27 because the light blocking layer 22 is provided between the metal bridge 35 and the counter electrode 27. This allows a reduction in parasitic capacitance between the sensor electrode 31 and the counter electrode 27.
Furthermore, as shown in (a) and (b) of FIG. 46, the light blocking layer 22 is provided between the insulating layer 25 and the CF layer 26. This makes it easy to align the light blocking layer 22 with the CF layers 26 of different colors when the light blocking layer 22 is formed so as to be positioned between the CF layers 26 of different colors.
<Example 2 of Arrangement of the Light Blocking Layer 22>
According to the present embodiment, as with Embodiment 5, the arrangement of the light blocking layer 22 shown in (a) and (b) of FIG. 46 is merely an example, and is not limited to the arrangement in which the light blocking layer 22 is provided between the insulating layer 25 and the CF layer 26.
FIG. 47 is a cross-sectional view schematically showing another configuration of the substrate 20 according to the present embodiment. (a) and (b) of FIG. 48 are cross sections schematically showing a configuration of a main part of the substrate 20 in which a light blocking layer 22 is provided between an insulating substrate 21 and electrodes 132.
As shown in FIG. 47 and (a) and (b) of FIG. 48, the light blocking layer 22 can be provided between the insulating substrate 21 and the electrodes 132.
The substrate 20 shown in (a) and (b) of FIG. 48 can be fabricated as follows:
First, a light blocking layer 22 (BM) is formed by forming, on an insulating substrate 21, a film made of a material having a light blocking property and then patterning the film. Then, as in the steps shown in (a) through (e) of FIG. 45, electrodes 132, an insulating layer 34, a metal bridge 35, an insulating layer 25, a CF layer 26, and a counter electrode 27 are formed in this order on the insulating substrate 21 on which the light blocking layer 22 has been formed. Note that the light blocking layer 22 can be formed in a manner similar to that shown in (d) of FIG. 40, except that the light blocking layer 22 in the present example is formed on the insulating substrate 21 instead of on the insulating layer 25.
According to the present embodiment also, as shown in (a) and (b) of FIG. 43, the metal bridge 35 serves also as a light blocking layer. This makes it not quite necessary to additionally provide a light blocking layer. Therefore, in a case where, as shown in (a) and (b) of FIG. 43, a light blocking layer is not additionally provided, it is possible to reduce the number of components and to therefore reduce processing cost.
However, as described above, the disconnecting lines 39 are provided in the metal bridge 35 so that no electricity travels between the electrodes 132 which are provided adjacently. Under the circumstances, by providing the light blocking layer 22 in addition to the metal bridge 35, it is possible to prevent light from leaking from cross sections of the metal bridge 35, which is in the mesh pattern, or the like.
<Example 1 of Formation of Disconnecting Lines 39>
The present embodiment employs the example configuration in which the disconnecting lines 39 are provided in respective spaces between the electrodes 132 which are adjacently provided. However, it is only necessary to provide at least one disconnecting line 39 in each of the spaces between the electrodes 132. That is, two or more disconnecting lines 39 can be provided in each of the spaces.
For example, the present embodiment can also employ, as with Embodiments 2 and 3, a configuration (not illustrated) in which two disconnecting lines 39 are provided in the metal bridge 35 in each of the spaces between the electrodes 132 which are provided adjacently along the X-axis.
This configuration causes metal wiring parts (not illustrated), which are not electrically connected to the electrodes 132 and are each electrically in the form of a floating island, to be formed in the metal bridge 35, by the disconnecting lines 39, in the spaces between the electrodes 132 which are adjacent to each other along the X-axis (to be more precise, in the spaces between the metal wiring parts 35d that are electrically connected to the electrodes 132).
Therefore, it is possible to certainly prevent the metal wiring parts 35d, which are provided adjacently along the X-axis, from being short-circuited, and therefore to prevent a decrease in yields caused by such short circuits.
In addition, since the metal wiring parts, which are not electrically connected to the electrodes 132, are provided between the spaces between the metal wiring parts 35d, it is possible to reduce a capacitance that does not vary depending on whether or not an object to be detected is in contact.
Hence, it is possible to reduce the CR time constant and it is therefore easy for the touch panel to carry out a position detecting operation.
<Example 2 of Formation of Disconnecting Lines 39>
FIG. 49 is a plan view showing another example in which the disconnecting lines 39 are provided in the metal bridge 35 shown in FIG. 42. Note that, in FIG. 49, the contact holes 137 and the electrodes 132 are indicated by chain double-dashed lines for the purpose of showing the positional relations between the metal wiring parts of the metal bridge 35 and the contact holes 137.
According to the example shown in FIG. 49, (i) the plurality (four in the example shown in FIG. 49) of contact holes 137 per electrode 132 are provided along the Y-axis and (ii) two contact holes 137 are provided, along the Y-axis, at each of end parts of the electrode 132, which end parts are first and second end parts along the Y-axis.
Two (first and second) disconnecting lines 39 each extending along the X-axis are provided between (i) contact holes 137 each of which is one of the two contact holes 137 in each of the first end parts, which one is located closer to a center part of the electrode 132 than is the other one and (ii) contact holes 137 each of which is one of the two contact holes 137 in each of the second end parts, which one is located closer to the center part of the electrode 132 than is the other one. Furthermore, additional disconnecting lines 39 each extending along the Y-axis are provided, along the electrodes 132 provided adjacently, in regions located outer along the Y-axis than the first and second disconnecting lines 39. In other words, according to the example shown in FIG. 49, two sets of disconnecting lines 39, each of which two sets is in a comb-teeth shape, are provided so that their respective teeth parts face opposite directions.
According to the example shown in FIG. 49, therefore, a metal wiring part 35e, which is not electrically connected to the electrodes 132, is formed between the first and second disconnecting lines 39 each of which is formed in the metal bridge 35 so as to extend along the X-axis.
It is possible to reduce the resistance of the counter electrode 27 by (i) thus forming the metal wiring part 35e, which is not electrically connected to the electrodes 132, between metal wiring parts 35e which are electrically connected to the electrodes 132 via the contact holes 137 in the metal bridge 35 and (ii) electrically connecting, as in Embodiment 3, the metal wiring part 35e to the counter electrode 27.
Embodiment 8
Another embodiment of the present invention is described below with reference to (a) and (b) of FIG. 50 through FIG. 52. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiments 1 through 7 are each assigned an identical reference sign, and as such, are not described here.
(a) of FIG. 50 is a plan view schematically showing a configuration of a substrate 20 according to the present embodiment. (b) of FIG. 50 is a cross-sectional view showing the substrate 20 as taken along the line I-I in (a) of FIG. 50.
Further, (a) of FIG. 51 is a plan view schematically showing a configuration of a liquid crystal panel 2 according to the present embodiment. (b) of FIG. 51 is a cross-sectional view showing the liquid crystal panel 2 as taken along the line II-II in (a) of FIG. 51.
As shown in (b) of FIG. 50 and (b) of FIG. 51, the metal bridge 35 includes an outer peripheral part 90 (outer peripheral edge) that serves as a connection part (sealing part) to connect the substrate 20 and the substrate 10 to each other, the outer peripheral part 90 being electrically disconnected from the electrodes 32 and 33.
The present embodiment is configured such that the counter electrode 27 is electrically connected to the outer peripheral part 90 (shielded line) of the metal bridge 35. That is, as shown in (b) of FIG. 51, the counter electrode 27 is electrically connected to the shielded line of the metal bridge 35 at the sealing part at which the seal material 60 is provided. This makes it possible to reduce the resistance of the counter electrode 27 at the sealing part as well, thus making it possible to reduce the CR time constant.
Mounting the substrate 20 in the liquid crystal panel 2 as described above makes it possible to reduce the resistance of the counter electrode 27 as described above, thus making it possible to improve the display performance of the liquid crystal panel 2.
Connecting the counter electrode 27 and the shielded line to each other makes it possible to prevent noise from, for example, wires for use in TFTs.
Further, as shown in (b) of FIG. 50 and (b) of FIG. 51, the present embodiment is configured such that the counter electrode 27 is formed (as a film) on the metal bridge 35 at the outer peripheral part of the substrate 20 so that the metal bridge 35 and the counter electrode 27 are electrically connected to each other.
The present embodiment can thus omit the production step of electrically connecting the metal bridge 35 and the counter electrode 27 to each other, that is, the step of forming contact holes 28 via which the metal wiring parts 35c of the metal bridge 35 and the counter electrode 27 are electrically connected to each other, the metal wiring parts 35c being electrically connected to neither of the electrodes 32 and 33. This makes it possible to simplify the process for producing the substrate 20 and reduce production costs.
The touch panel layer 23 has lead wires (not illustrated) that are connected to a wiring pattern (not illustrated) in an active matrix layer 12 (TFT pixel section) of the substrate 10 via electrically conductive particles, such as gold beads, which are contained in the seal material 60.
<Modifications>
FIG. 52 is a cross-sectional view schematically showing a liquid crystal panel 2 according to the present embodiment. FIG. 52 is a cross-sectional view showing the liquid crystal panel 2 as taken along the line II-II in (a) of FIG. 51.
FIG. 51 shows an example case where a CF layer 26 is so provided as to be adjacent, via the counter electrode 27, to the region in which the seal material 60 is provided.
FIG. 52 shows a case where the CF layer 26 is formed in a light blocking region provided by the light blocking layer 22. This allows the seal material 60 to block light around a boundary edge of the CF layer 26, thus making it possible to prevent light leakage at a peripheral edge of the CF layer 26.
Embodiment 9
Another embodiment of the present invention is described below with reference to FIG. 53 and (a) through (d) of FIG. 54. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiments 1 through 8 are each assigned an identical reference sign, and as such, are not described here.
The present embodiment is particularly described below by taking, as an example, a case in which a metal BM made of metal is employed as the light blocking layer 22 of Embodiment 7 and the light blocking layer 22 is electrically connected to the counter electrode 27.
Therefore, a configuration of a main part of the substrate 20 according to the present embodiment is identical with that shown in the cross-sectional view of FIG. 37, and the constituent layers are stacked in the order shown in FIG. 37.
FIG. 53 is a plan view showing a relation of connection between the light blocking layer 22 and the counter electrode 27. (a) of FIG. 54 a cross-sectional view taken along the line Y7-Y7 shown in FIG. 53, (b) of FIG. 54 is a cross-sectional view taken along the line Y8-Y8 shown in FIG. 53, (c) of FIG. 54 is a cross-sectional view taken along the line X10-X10 shown in FIG. 53, and (d) of FIG. 54 is a cross-sectional view taken along the line X11-X11 shown in FIG. 53.
Note that each of FIG. 53 and (a) through (d) of FIG. 54 partially shows the electrodes 32 and 33 and the metal bridge 35. Moreover, the counter electrode 27 is a solid transparent electrode, and therefore the counter electrode 27 is depicted by circumferential dotted lines in FIG. 53.
The light blocking layer 22 is formed by a low-resistance conductive film. Moreover, the light blocking layer 22 is formed so as to overlap with the metal bridge 35 when viewed in the plan view as shown in FIG. 53. Further, the light blocking layer 22 is electrically connected to the counter electrode 27 via a plurality of contact holes 29 as shown in FIG. 53 and (a) and (c) of FIG. 54.
<Process for Fabricating a Substrate 20>
The following description will discuss a process for fabricating the substrate 20 according to the present embodiment with reference to (a) through (f) of FIG. 55. Note that (a) through (f) of FIG. 55 are cross-sectional views schematically showing steps of a process for fabricating the substrate 20 with the steps arranged in process sequence, and each correspond to the Y7-Y7 cross section of FIG. 53.
Note that steps shown in (a) through (c) of FIG. 55 are identical with those shown in (a) through (c) of FIG. 19. Therefore, descriptions of the steps shown in (a) through (c) of FIG. 55 are omitted here.
In the step shown in (d) of FIG. 55, an insulating layer 25 is formed so as to entirely cover a surface of the insulating substrate 21 on which surface the electrodes 32 and 33 and the metal bridge 35 have been formed, in a manner similar to that shown in (d) of FIG. 19.
Subsequently, a light blocking layer 22 (BM) is formed over the insulating substrate 21 by (i) forming a metal film from a metal material by sputtering or the like on the insulating layer 25 and then (ii) patterning the metal film by photolithography or the like.
Examples of the metal material of which the light blocking layer 22 is made encompass (i) low-resistance metal such as titanium (Ti), copper (Cu), gold (Au), aluminum (Al), tungsten (W), zinc (Zn), nickel (Ni), tin (Sn), chromium (Cr), molybdenum (Mo), tantalum (Ta), (ii) metal compounds thereof, and (iii) metal silicides thereof.
Note that, also in the present embodiment, the light blocking layer 22 is patterned so that the light blocking layer 22 covers switching elements and wires such as gate lines, source lines, and auxiliary capacitor lines in the substrate 10 when it is included in the liquid crystal panel 2, as with the metal bridge 35. In the present embodiment also, an identical photolithographic mask can be used as a pattern mask for the light blocking layer 22 and a pattern mask for the metal bridge 35.
Next, different colors (e.g., red (R), green (G), and blue (B)) of CF layers 26 are formed in openings in the light blocking layer 22 as show in (d) of FIG. 55 by patterning with the use of photolithography or by the use of a well-known method such as ink-jet printing, laminating, or pigment dispersion.
Then, each of the CF layers 26 is patterned by etching with photolithography or the like so that openings 26a are formed which serve as contact holes 29 (see (e) of FIG. 55).
Subsequently, a counter electrode 27 is formed as shown in (f) of FIG. 55, in a manner similar to that shown in (e) of FIG. 19. In this case, metal wires are formed, also in the openings 26a, from a transparent conductive film made of a transparent conductive material of which the counter electrode 27 is made, and as such the counter electrode 27 and the contact holes 29, which are made of the transparent conductive film, are formed as shown in (f) of FIG. 55.
Lastly, an alignment film (not illustrated) is formed on the counter electrode 27 if needed, and the substrate 20 is thus fabricated.
The respective thicknesses of, for example, the CF layer 26, the light blocking layer 22, the counter electrode 27, and the alignment film are not particularly limited, and can thus be selected as conventional.
According to the present embodiment, the light blocking layer 22 which is made of the low-resistance conductor such as metal is electrically connected to the counter electrode 27, and this allows a reduction in resistance of the counter electrode 27. From this, it is possible to decrease a CR time constant and increase an SN ratio. Therefore, it is possible to provide a touch panel substrate and an electro-optic device which are high in position detection performance and can carry out a stable position detecting operation.
Embodiment 10
Another embodiment of the present invention is described below with reference to (a) and (b) of FIG. 56. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiments 1 through 9 are each assigned an identical reference sign, and as such, are not described here.
(a) of FIG. 56 is a plan view schematically showing a configuration of the substrate 20 according to the present embodiment. (b) of FIG. 56 is a cross-sectional view taken along the line III-III of (a) of FIG. 56.
In the substrate 20 according to the present embodiment, a sensor electrode 31 (electrodes 32 and 33), an insulating layer 34, a metal bridge 35, an insulating layer 25, a light blocking layer 22 made of a low-resistance conductor such as metal, a CF layer 26, and a counter electrode 27 are stacked on an insulating substrate 21 in this order, as with Embodiment 9.
In the present embodiment, the counter electrode 27 is electrically connected to the light blocking layer 22 at an outer peripheral part (outer peripheral edge) of the liquid crystal panel 2 which outer peripheral part serves as a sealing part when it is included in the liquid crystal panel 2. This allows a reduction in resistance of the counter electrode 27 at the sealing part. It is therefore possible to reduce a CR time constant.
Moreover, according to the present embodiment, it is possible to omit the step of electrically connecting the light blocking layer 22 to the counter electrode 27, i.e., the step of forming contact holes 29 in the substrate 20. This allows a simplification of the process for manufacturing the substrate 20 and therefore a reduction in manufacturing cost.
Embodiment 11
Another embodiment of the present invention is described below with reference to (a) and (b) of FIG. 57 through (a) through (f) of FIG. 58. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiments 1 through 10 are each assigned an identical reference sign, and as such, are not described here.
Each of (a) and (b) of FIG. 57 is a cross-sectional view schematically showing a configuration of the substrate 20 according to the present embodiment. (a) of FIG. 57 corresponds to a Y1-Y1 cross-sectional view of FIG. 4, and (b) of FIG. 57 corresponds to an X2-X2 cross-sectional view of FIG. 4.
As shown in (a) and (b) of FIG. 57, in the substrate 20, a sensor electrode 31 (electrodes 32 and 33), an insulating layer 34, a metal bridge 35, an insulating layer 25, a CF layer 26, a light blocking layer 22 made of a low-resistance conductor such as metal, and a counter electrode 27 are stacked on the insulating substrate 21 in this order.
(a) through (f) of FIG. 58 are cross-sectional views showing steps of a process for fabricating the substrate 20 according to the present embodiment with the steps arranged in process sequence, and each correspond to the Y1-Y1 cross section of FIG. 4.
According to the present embodiment, the light blocking layer 22 is formed on the CF layer 26, and the counter electrode 27 is formed on the light blocking layer 22 as shown in (a) and (b) of FIG. 57 and (a) through (f) of FIG. 58.
With the configuration of the present embodiment, the light blocking layer 22 is directly electrically connected to the counter electrode 27.
From this, according to the present embodiment, it is possible to omit the step of electrically connecting the light blocking layer 22 to the counter electrode 27, i.e., the step of forming contact holes 29. This allows a simplification of the process for manufacturing the substrate 20 and therefore a reduction in manufacturing cost.
Embodiment 12
Another embodiment of the present invention is described below with reference to (a) and (b) of FIG. 59 through (a) through (f) of FIG. 60. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiments 1 through 11 are each assigned an identical reference sign, and as such, are not described here.
Each of (a) and (b) of FIG. 59 is a cross-sectional view schematically showing a configuration of the substrate 20 according to the present embodiment. (a) of FIG. 59 corresponds to the Y1-Y1 cross-sectional view of FIG. 4, and (b) of FIG. 59 corresponds to the X2-X2 cross-sectional view of FIG. 4.
As shown in (a) and (b) of FIG. 59, in the substrate 20, a sensor electrode 31 (electrodes 32 and 33), an insulating layer 34, a metal bridge 35, an insulating layer 25, a light blocking layer 22 made of a low-resistance conductor such as metal, a CF layer 26, a metal layer 151, and a counter electrode 27 are stacked on the insulating substrate 21. The metal layer 151 is electrically connected to the counter electrode 27. The light blocking layer 22 is electrically connected to the metal layer 151 and the counter electrode 27 via contact holes 152 which are formed in the CF layer 26 and the metal layer 151.
(a) through (f) of FIG. 60 are cross-sectional views showing steps of a process for fabricating the substrate 20 according to the present embodiment with the steps arranged in process sequence, and each correspond to the Y1-Y1 cross section of FIG. 4.
According to the present embodiment, as shown in (e) of FIG. 60, the CF layer 26 is formed as shown in (d) of FIG. 58 of Embodiment 11, and then the low-resistance metal layer 151 is formed on the CF layer 26 by sputtering or the like in, for example, a pattern similar to that of the light blocking layer 22.
Then, the CF layer 26 and the metal layer 151 are patterned by etching with photolithography or the like so that openings 141 which serve as the contact holes 152 are formed (see (e) of FIG. 60).
After that, a transparent conductive film is formed also in the openings 141 which have been formed in the CF layer 26 and the metal layer 151 in the step shown in (e) of FIG. 60, and thus the counter electrode 27 and the contact holes 152 are formed.
Note that the metal layer 151 can be made of a conductor such as a low-resistance metal material of which the light blocking layer 22 is made.
According to the present embodiment, the light blocking layer 22 and the metal layer 151 each of which is made of a conductor are electrically connected to the counter electrode 27, and this makes it possible to further reduce resistance of the counter electrode 27 as compared to Embodiments 9 through 11. From this, it is possible to further enhance a position detection performance of the touch panel and to carry out a stable position detecting operation.
Embodiment 13
Another embodiment of the present invention is described below with reference to (a) and (b) of FIG. 61 through FIG. 63. For convenience of explanation, constituent elements of the present embodiment that are identical in function to their respective corresponding constituent elements used in Embodiments 1 through 12 are each assigned an identical reference sign, and as such, are not described here.
(a) of FIG. 61 is a plan view showing a display driving terminal and a touch panel terminal of the liquid crystal panel 2. (b) of FIG. 61 is an enlarged view of a portion corresponding to the touch panel terminal (encircled region) shown in (a) of FIG. 61.
Each of FIGS. 62 and 63 is another plan view showing a display driving terminal and a touch panel terminal of the liquid crystal panel 2.
As shown in (a) of FIG. 61, the liquid crystal panel 2 is arranged such that both a front surface of the display driving terminal and that of the touch panel terminal face in the same direction (vertically upward from the plane of paper of (a) of FIG. 61).
As shown in (b) of FIG. 61, the terminal provided on the front surface of the touch panel is connected, via contact parts, to a signal wire (touch panel wire) on a back surface. Specifically, the touch panel terminal and the signal wire on the back surface are electrically connected to each other at contact parts via electrically conductive particles, such as gold beads, which are provided inside the sealing part.
This makes it possible to form a display driving terminal and a touch panel terminal so that they face in the same direction, thus making it possible to connect the display driving terminal and the touch panel terminal to circuits on the side of one of the substrates 10 and 20, namely, on the side of the substrate 10.
The terminal areas in a frame region of the liquid crystal panel 2 are, however, not limited to the above configuration, and may be arranged as shown, for example, in FIG. 62 or 63.
The liquid crystal panel 2 shown in FIG. 62 is configured such that the respective terminal areas of the substrates 10 and 20 are each partially cut off obliquely and placed so as not to overlap each other, so that the front surface of the touch panel terminal and that of the display driving terminal face each other.
The liquid crystal panel 2 shown in FIG. 63 is configured such that the substrates 10 and 20 are drawn in opposite directions to be placed so as not to entirely overlap each other, so that the substrates 10 and 20 have their respective terminal areas. The liquid crystal panel 2 shown in FIG. 63 is therefore configured such that the front surface of the touch panel terminal and that of the display driving terminal face each other and are symmetric with respect to the center of the liquid crystal panel 2.
The above configuration of the terminal areas is commonly applicable to the substrate 20 of any of the above-described embodiments.
<Modification>
The embodiments described above have each been described by taking, as an example, a case where the touch panel layer 23 is provided on a counter substrate, in particular, a CF substrate. The present invention is, however, not limited to such a configuration. The touch panel layer 23 may alternatively be provided on an array substrate such as an active-matrix substrate.
Providing the touch panel layer 23 on a counter substrate allows signal lines (for example, gate lines and source lines) provided on an array substrate for image display to be separated from the touch panel layer 23. The above configuration can thus, in comparison to the case where the touch panel layer 23 is provided on an array substrate, further reduce the occurrence of noise and improve the sensitivity of the touch panel.
<Summary of Main Points>
As above described, the touch panel substrate according to an aspect of the present invention is a touch panel substrate that is used as one of a pair of substrates between which an electro-optic element is sandwiched and that is provided with a position detecting electrode which detects, according to a change in capacitance, a position given by coordinates indicating an object to be detected, the touch panel substrate including: an insulating substrate; an electro-optic element driving electrode which applies an electric field to the electro-optic element; and the position detecting electrode, the position detecting electrode being provided between the insulating substrate and the electro-optic element driving electrode and being insulated from the electro-optic element driving electrode, the position detecting electrode including at least a plurality of first electrodes which are arranged along a first direction and each of which is made up of a transparent electrode, the first electrodes at least being electrically connected to a grid of metal wires via an insulating layer.
According to the configuration, the resistance of the position detecting electrode can be reduced while the optical transmittance and the area of the transparent region are ensured. Therefore, mounting the touch panel substrate in a display panel makes it possible to reduce the resistance of the position detecting electrode while ensuring the aperture ratio of the display panel.
Moreover, it is possible to reduce the resistance of the position detecting electrode as described above, and this makes it possible to reduce the CR time constant.
Therefore, according to the configuration, it is possible to provide the touch panel substrate that is high in position detection performance and capable of carrying out a stable position detecting operation.
According to the touch panel substrate, it is preferable that the metal wires serve also as a light blocking layer.
According to the configuration, the metal wires serve also as a light blocking layer, and therefore another light blocking layer does not necessarily need to be provided. Therefore, in a case where another light blocking layer is not provided, it is possible to reduce the number of components and accordingly to reduce processing cost.
Note that “the metal wires serve also as a light blocking layer” indicates that the metal wires serve also as a light blocking layer which is necessary when the touch panel substrate is incorporated into a cell of an electro-optic device such as a display panel or a display device. Specifically, in a case where the touch panel substrate is mounted in the display panel, the metal wires are formed, in a region in which a grid-shaped light blocking layer is to be formed (e.g., formed in a shape identical with that of the light blocking layer), so that the metal wires serve also as the light blocking layer which is provided between pixels.
It is preferable that the metal wires are sandwiched between the position detecting electrode and the electro-optic element driving electrode.
Providing the metal wires so that they are closer to the electro-optic element driving electrode than the position detecting electrode makes it possible to distance the position detecting electrode and the electro-optic element driving electrode as much as possible from each other, thus making it possible to reduce the parasitic capacitance between the position detecting electrode and the electro-optic element driving electrode. Moreover, since the metal wires are in the shape of wires (i.e., in a linear-shaped pattern), the parasitic capacitance between the metal wires and the electro-optic element driving electrode is small. Therefore, it is possible to provide the touch panel substrate that is high in position detection performance, capable of carrying out a stable position detecting operation, and used in an in-cell touch panel.
It is preferable that an organic insulating layer is sandwiched as an insulating layer at least either between the metal wires and the position detecting electrode or between the metal wires and the electro-optic element driving electrode.
An organic insulating film can be made thicker than and be lower in relative permittivity than an inorganic insulating film.
Therefore, because of the organic insulating layer (i.e., a layer made up of an organic insulating film) sandwiched either between the metal wires and the position detecting electrode or between the metal wires and the electro-optic element driving electrode, the parasitic capacitance between the position detecting electrode and the electro-optic element driving electrode can be reduced in terms of both an increase in film thickness and a reduction in relative permittivity.
According to the touch panel substrate, it is preferable that the position detecting electrode further includes a plurality of second electrodes arranged along a second direction perpendicular to the first direction and insulated from the first electrodes, the plurality of second electrodes each being made up of a transparent electrode; and the first electrodes and the second electrodes are formed in a same plane.
According to the configuration, the first electrodes and the second electrodes are formed in a same plane. Therefore, even in the case where the position detecting electrode includes the first electrodes and the second electrodes, it is possible to distance the first and second electrodes from the electro-optic element driving electrode. With the configuration, it is possible to reduce a parasitic capacitance between the first and second electrodes and the electro-optic element driving electrode (i.e., a parasitic capacitance between the position detecting electrode and the electro-optic element driving electrode), as compared with a case where the first electrodes are provided in a layer which is different from a layer in which the second electrodes are provided.
According to the configuration, the first electrodes and the second electrodes are formed in a same plane, and it is therefore possible to distance the first and second electrodes from the electro-optic element driving electrode. Therefore, even in a case where the first electrodes and the second electrodes are formed in a sheet-shaped pattern (planar-shaped pattern), it is possible to make the parasitic capacitance smaller. As such, it is possible to make the parasitic capacitance smaller while ensuring the magnitude of the detection signal.
Moreover, according to the configuration, since the first electrodes and the second electrodes are formed in a same plane, it is possible to simultaneously form the first electrodes and the second electrodes with a same material. This allows a reduction in processing cost.
According to the touch panel substrate, it is preferable that, in the plane in which the first electrodes and the second electrodes are formed, at least the first electrodes are in an isolated pattern in which the first electrodes are isolated from each other along a direction intersecting a direction along which the other electrodes are arranged; and the metal wires make bridge connections between at least the first electrodes of the first electrodes and the second electrodes in such a way as to bridge between the at least first electrodes along the direction intersecting the direction along which the other electrodes are arranged.
According to the configuration, at least either the first electrodes or the second electrodes are bridge-connected to each other via the metal wires along the direction intersecting the direction along which the other electrodes are arranged. This configuration can connect the electrodes to each other while preventing the first electrodes from being electrically connected to the second electrodes.
Moreover, in the case where the first electrodes and the second electrodes are transparent electrodes and at least either the first electrodes or the second electrodes are bridge-connected to each other via the metal wires as above described, it is possible to reduce the resistance of the position detecting electrode while the area of the transparent region is ensured. Therefore, mounting the touch panel substrate in a display panel makes it possible to reduce the resistance of the position detecting electrode while ensuring the aperture ratio of the display panel.
Moreover, it is possible to reduce the resistance of the position detecting electrode as described above, and this makes it possible to reduce the CR time constant.
It is preferable that the metal wires make bridge connections between each separate one of the electrodes and another via at least one contact hole formed in an insulating layer sandwiched between the metal wires and electrodes connected via the metal wires.
The foregoing configuration allows bridge connections to be easily made by the grid of metal wires. Therefore, the process can be simplified, and the processing cost can be reduced.
It is preferable that the contact holes are formed at branch line parts of the metal wires, the branch line parts intersecting trunk lines connecting electrodes connected via the metal wires.
Since the contact holes are formed at branch line parts, not the trunk lines, of the metal wires, the foregoing configuration makes it possible to prevent a disconnection and improve yields.
It is preferable that two or more of the contact holes are provided for each electrode.
According to the configuration, it is possible to ensure the area of the connection parts between the metal wires and the electrodes and reduce the resistance of the position detecting electrode, thus reducing the CR time constant.
Further, it is preferable that the contact holes be so formed as to bridge a plurality of wires extending parallel to a trunk line of the metal wires, the trunk line connecting electrodes connected via the metal wires.
It is here preferable, for example, that the contact holes be so formed as to bridge a plurality of grid portions of the metal wires.
The foregoing configuration makes it possible to ensure the area of the connection parts between the metal wires and the electrodes and reduce the resistance of the position detecting electrode, thus reducing the CR time constant.
The touch panel substrate is preferably configured such that: in the plane in which the first electrodes and the second electrodes are formed, the second electrodes are connected to each other via transparent connecting wires; the first electrodes and the second electrodes are each electrically connected to the metal wires via the contact holes; and the metal wires have disconnections between the contact holes provided for the first electrodes and contact holes provided for the second electrodes, so that no electricity travels between the first electrodes and the second electrodes.
For example, it is preferable that the metal wires have, between the contact holes provided for the first electrodes and the contact holes provided for the second electrodes, disconnecting lines that divide the metal wires into a plurality of metal wiring parts, the metal wires being divided by the disconnecting lines into those metal wiring parts connected to the first electrodes and those metal wiring parts connected to the second electrodes.
The foregoing configuration makes it possible for each of the first and second electrodes to be electrically connected to the metal wire, without causing electricity to travel between the first and second electrodes. This makes it possible to reduce the resistance of the position detecting electrode, thus making it possible to reduce the CR time constant.
It is preferable that the second electrodes are provided with the contact holes at electrode edge parts connected to each other via the connecting wires.
The foregoing configuration makes it possible to reduce the area in which electricity travels through the transparent connecting wires alone. This makes it possible to reduce the resistance of the position detecting electrode, thus making it possible to reduce the CR time constant.
It is preferable that the metal wires have (1) at least one disconnecting line which divides the metal wires into a plurality of metal wiring parts, the at least one disconnecting line being between the contact holes provided for the first electrodes and contact holes provided for the second electrodes; and (2) metal wiring parts which are divided by the at least one disconnecting line between the contact holes provided for the first electrodes and the contact holes provided for the second electrodes and which are not electrically connected to the position detecting electrode.
According to the configuration, it is possible to form, between the contact holes provided for the first electrodes and the contact holes provided for the second electrodes, floating islands by metal wiring parts which are not electrically connected to the position detecting electrode (i.e., which are not electrically connected to any of the first electrodes and the second electrodes).
This makes it possible to prevent a short circuit between those metal wiring parts connected to the first electrodes and those metal wiring parts connected to the second electrodes. This makes it possible to suppress a reduction in yield due to such a short circuit.
Further, the foregoing configuration makes it possible to cause cross capacitances (capacitances that do not vary depending on whether or not an object to be detected is in contact) that are formed between the first electrodes and the second electrodes to be reduced by the floating islands (i.e., metal wiring parts not electrically connected to the position detecting electrode). This makes it possible to reduce the CR time constant and makes it easy for the touch panel to carry out a position detecting operation.
Furthermore, the foregoing configuration makes it possible to form, without forming another metal layer, metal wiring parts electrically isolated from the position detecting electrode. In other words, the foregoing configuration makes it possible to form, without increasing the number of components or the film thickness, metal wiring parts electrically isolated from the position detecting electrode.
According to the touch panel substrate, it is possible that: the position detecting electrode includes only the plurality of first electrodes; an insulating layer is provided between the metal wires and the first electrodes; the first electrodes are each electrically connected to the metal wires via at least one contact hole formed in the insulating layer; and the metal wires have disconnections between at least one contact hole, which is provided for one of any adjacent two of the first electrodes, and another at least one contact hole, which is provided for the other of the any adjacent two of the first electrodes, so that no electricity travels between the any adjacent two of the first electrodes.
According to the configuration, it is possible to cause the first electrodes to be each electrically connected to the metal wire while preventing electricity from traveling between any adjacent two of the first electrodes. This allows a reduction in resistance of the position detecting electrode, and it is therefore possible to reduce the CR time constant.
In a case where the position detecting electrode includes only the plurality of first electrodes, the metal wires preferably have (1) at least one disconnecting line which divides the metal wires into a plurality of metal wiring parts, the at least one disconnecting line being between the contact hole provided for one of any adjacent two of the first electrodes and the contact hole provided for the other of the any adjacent two of the first electrodes; and (2) metal wiring parts which are divided by the at least one disconnecting line between the contact hole provided for one of the any adjacent two of the first electrodes and the contact hole provided for the other of the any adjacent two of the first electrodes and which are not electrically connected to the position detecting electrode.
According to the configuration, it is possible to form, between the contact hole provided for one of the any adjacent two of the first electrodes and the contact hole provided for the other of the any adjacent two of the first electrodes, floating islands by metal wiring parts which are not electrically connected to the position detecting electrode (i.e., by metal wiring parts which are not electrically connected to the first electrodes).
This makes it possible to prevent a short circuit, in the metal wires, between the any adjacent two of the first electrodes. This makes it possible to suppress a reduction in yield due to such a short circuit.
Further, the foregoing configuration makes it possible to cause capacitances, which do not vary depending on whether or not an object to be detected is in contact, to be reduced by the floating islands (i.e., metal wiring parts not electrically connected to the position detecting electrode). This makes it possible to reduce the CR time constant and makes it easy for the touch panel to carry out a position detecting operation.
Furthermore, the foregoing configuration makes it possible to form, without forming another metal layer, metal wiring parts electrically isolated from the position detecting electrode. In other words, the foregoing configuration makes it possible to form, without increasing the number of components or the film thickness, metal wiring parts electrically isolated from the position detecting electrode.
It is preferable that those metal wiring parts which are not connected to the position electrode wire are electrically connected to the electro-optic element driving electrode.
According to the configuration, metal wiring parts which are not connected to the position electrode wire are electrically connected to the electro-optic element driving electrode, and this makes it possible to reduce the resistance of the electro-optic element driving electrode. This allows a reduction in CR time constant. In a case where the touch panel substrate is mounted in a display panel, the resistance of the electro-optic element driving electrode can be reduced, and it is therefore possible to improve a display performance of the display panel.
It is preferable that the metal wires have outer peripheral parts which serve as connecting parts with the other one of the pair of substrates and which are electrically disconnected from the position detecting electrode, and the electro-optic element driving electrode is electrically connected to the outer peripheral parts of the metal wires.
According to the configuration, it is possible to reduce the resistance of the electro-optic element driving electrode. This allows a reduction in CR time constant. In a case where the touch panel substrate is mounted in a display panel, the resistance of the electro-optic element driving electrode can be reduced, and it is therefore possible to improve a display performance of the display panel.
It is preferable that the metal wires are provided between the position detecting electrode and the electro-optic element driving electrode, and a color filter of different colors is provided between the position detecting electrode and the metal wires.
In a case where the color filter is thus formed between the position detecting electrode and the metal wires, it is possible to distance the position detecting electrode from the electro-optic element driving electrode. This allows a reduction in parasitic capacitance between the position detecting electrode and the electro-optic element driving electrode.
As above described, the electro-optic device of an aspect of the present invention includes an electro-optic element and a pair of substrates between which the electro-optic element is sandwiched, one of the pair of substrates being the touch panel substrate described above.
According to the configuration, the above described touch panel substrate is used as one of the pair of substrates, and it is therefore possible to provide a touch-panel-integrated electro-optic device which includes an in-cell touch panel, is high in position detection performance, and can carry out a stable position detecting operation.
The present invention is not limited to the embodiments, but can be altered by a skilled person in the art within the scope of the claims. An embodiment derived from a proper combination of technical means disclosed in respective different embodiments is also encompassed in the technical scope of the present invention.
INDUSTRIAL APPLICABILITY
The present invention is applicable to a touch panel substrate that is used in an in-cell touch panel and to an electro-optic device including such a touch panel substrate. Examples of the electro-optic device include display panels such as liquid crystal panels, organic EL display panels, and electrophoretic display panels, display devices in which such display panels are used, and viewing-angle control panels.
REFERENCE SIGNS LIST


    1 Liquid crystal display device (electro-optic device)
    2 Liquid crystal panel (electro-optic device)
    3 Backlight
    4 Liquid crystal cell
    5 Polarization plate
    6 Polarization plate
    7 Wave plate
    8 Wave plate
    10 Substrate
    11 Insulating substrate
    12 Active-matrix layer
    20 Substrate (touch panel substrate)
    21 Insulating substrate
    22 Light blocking layer
    23 Touch panel layer
    24 Resin layer
    25 Insulating layer
    26 CF layer (color filter)
    26a Opening
    27 Counter electrode
    28 Contact hole
    30 Liquid crystal layer (electro-optic element)
    31 Sensor electrode (position detecting electrode)
    32 Electrode (position detecting electrode)
    32a Electrode part
    32b Connection part
    33 Electrode (position detecting electrode)
    34 Insulating layer
    34a Opening
    35 Metal bridge
    35A Central trunk line
    35B Branch line part
    35a Electrode wiring part
    35b Metal wiring part
    35c Metal wiring part
    35d Metal wiring part
    35e Metal wiring part
    36 Connecting wire
    37 Contact hole
    38 Contact hole
    39 Disconnecting line
    40 Terminal area
    50 Liquid crystal layer
    60 Seal material
    70 Fingertip
    71 Capacitor
    90 Outer peripheral part
    100 Position detecting circuit
    101 Drive-line driving circuit
    102 Sense-line driving circuit
    103 Touch panel controller
    104 Timing controller
    111 Sampling circuit
    112 Storage capacitor
    113 Output amplifier
    114 Reset switch
    115 Measuring means
    132 Electrode (position detecting electrode)
    137 Contact hole
    141 Opening
    151 Metal layer
    152 Contact hole

## Claims

1. An electro-optic device comprising:
an electro-optic element; and
a pair of substrates between which the electro-optic element is provided,
one of the pair of substrates being a touch panel substrate that is provided with a position detecting electrode which detects, according to a change in capacitance, a position given by coordinates indicating an object to be detected, the touch panel substrate comprising:
an insulating substrate;
an electro-optic element driving electrode which applies an electric field to the electro-optic element; and
the position detecting electrode, the position detecting electrode being provided between the insulating substrate and the electro-optic element driving electrode and being insulated from the electro-optic element driving electrode, wherein
the position detecting electrode including at least a plurality of first electrodes which are arranged along a first direction and each of which is made up of a transparent electrode,
the first electrodes at least being electrically connected to a grid of metal wires via an insulating layer,
the metal wires also serve as a light blocking layer, and
the electro-optic element driving electrode and the position detecting electrode are located between the pair of substrates.

2. The electro-optic device as set forth in claim 1, wherein the metal wires are between the position detecting electrode and the electro-optic element driving electrode.

3. The electro-optic device substrate as set forth in claim 2, further comprising an organic insulating layer sandwiched as an insulating layer at least either between the metal wires and the position detecting electrode or between the metal wires and the electro-optic element driving electrode.

4. The electro-optic device as set forth in claim 2, wherein the insulating layer is between the metal wires and the electro-optic element driving electrode.

5. The electro-optic device as set forth in claim 2, wherein a color filter is between the metal wires and the electro-optic element driving electrode.

6. The electro-optic device as set forth in claim 1, wherein:
the position detecting electrode further includes a plurality of second electrodes arranged along a second direction perpendicular to the first direction and insulated from the first electrodes, the plurality of second electrodes each being made up of a transparent electrode; and
the first electrodes and the second electrodes are formed in a same plane.

7. The electro-optic device as set forth in claim 6, wherein:
in the plane in which the first electrodes and the second electrodes are formed, at least the first electrodes are in an isolated pattern in which the first electrodes are isolated from each other along a direction intersecting a direction along which the other electrodes are arranged; and
the metal wires make bridge connections between at least the first electrodes of the first electrodes and the second electrodes in such a way as to bridge between the at least first electrodes along the direction intersecting the direction along which the other electrodes are arranged.

8. The electro-optic device as set forth in claim 7, wherein the metal wires make bridge connections between each separate one of the electrodes and another via at least one contact hole defined in an insulating layer between the metal wires and electrodes connected via the metal wires.

9. The electro-optic device as set forth in claim 8, wherein the contact holes are provided at branch line portions of the metal wires, the branch line portions intersecting trunk lines connecting electrodes connected via the metal wires.

10. The electro-optic device as set forth in claim 8, wherein two or more of the contact holes are provided for each electrode.

11. The electro-optic device as set forth in claim 9, wherein:
in the plane in which the first electrodes and the second electrodes are provided, the second electrodes are connected to each other via transparent connecting wires;
the first electrodes and the second electrodes are each electrically connected to the metal wires via the contact holes; and
the metal wires have disconnections between the contact holes provided for the first electrodes and contact holes provided for the second electrodes, so that no electricity travels between the first electrodes and the second electrodes.

12. The electro-optic device as set forth in claim 11, wherein the second electrodes are provided with the contact holes at electrode edge parts connected to each other via the connecting wires.

13. The electro-optic device as set forth in claim 11, wherein:
the metal wires have at least one disconnecting line which divides the metal wires into a plurality of metal wiring portions, the at least one disconnecting line being between the contact holes provided for the first electrodes and contact holes provided for the second electrodes; and
the metal wires have metal wiring portions which are divided by the at least one disconnecting line between the contact holes provided for the first electrodes and the contact holes provided for the second electrodes and which are not electrically connected to the position detecting electrode.

14. The electro-optic device as set forth in claim 13, wherein those metal wiring portions which are not connected to the position detecting electrode are electrically connected to the electro-optic element driving electrode.

15. The electro-optic device as set forth in claim 1, wherein:
the position detecting electrode includes only the plurality of first electrodes;
an insulating layer is provided between the metal wires and the first electrodes;
the first electrodes are each electrically connected to the metal wires via at least one contact hole formed in the insulating layer; and
the metal wires have disconnections between at least one contact hole, which is provided for one of any adjacent two of the first electrodes, and another at least one contact hole, which is provided for the other of the any adjacent two of the first electrodes, so that no electricity travels between the any adjacent two of the first electrodes.

16. The electro-optic device as set forth in claim 1, wherein the metal wires have outer peripheral portions which serve as connecting portions with the other one of the pair of substrates and which are electrically disconnected from the position detecting electrode, and the electro-optic element driving electrode is electrically connected to the outer peripheral parts of the metal wires.