Black electrode, method of manufacturing black electrode substrate and display device

A black electrode substrate includes a transparent substrate having a first surface and a second surface opposite to the first surface, the second surface having a display region in a rectangular shape in plan view and an outer region outside of the display region, a black wiring forming a black electrode pattern that defines a plurality of pixel opening portions in the display region, and a transparent resin layer formed in the display region such that the transparent resin layer has the same rectangular shape as the display region in plan view. The black wiring has a laminated structure including a first black layer, a first indium-containing layer, a copper-containing layer, a second indium-containing layer, and a second black layer. The black wiring has a terminal portion formed such that the second indium-containing layer positioned in the outer region is exposed from the laminated structure.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a black electrode substrate provided with a metal wiring having low resistance and improving visibility thereof, a method of manufacturing a black electrode substrate and a display apparatus provided with the black electrode substrate.

The black electrode substrate is used for an in-cell type display device integrating capacitive type touch sensing functionality into the liquid crystal cell.

Discussion of the Background

Generally, display devices configured to use a touch panel are well known. The touch panel is disposed on a display surface of a display device which is provided in portable equipment such as smartphones or tablet computers. The touch panel is used as an input device which detects a contact between a finger or a pointer or the like and the touch panel. The major detection method for detecting a position of the finger or the pointer on the touch panel is a capacitive detection method which detects capacitive-change on the touch panel caused by a contact between the finger or the pointer and the touch panel.

The structure of providing the touch panel in the display device may increase the entire thickness or weight of the display device. Accordingly, the touch panel is considered as an unnecessary component in this structure of the display device. In this respect, a touch panel mainly using an organic film has been known, which reduces weight of the display device. However, even with this type of touch panel, it is difficult to avoid an increase of the entire thickness of the display device. Further, in the case where the display device is provided with the above-mentioned touch panel and high definition pixels, there is a disadvantage that necessary input (pen input) onto the touch panel is difficult to achieve.

Specifically, when the display device has high definition pixels of 400 ppi (pixel per inch), or 500 ppi or more, the pixel pitch is around 10 μm to 20 μm. Thus, if the display device has the above-mentioned touch panel and such high definition pixels, most of touch panels do not tolerate the pen pressure of the pen. Moreover, such display devices raise problems, including a problem of limited resolution in the opening configuring the input portion of the touch panel, or a problem of difficulty in achieving sufficient resolution of the touch panel to obtain high definition of the display device. Therefore, touch sensing technique for the touch panel is required to be sophisticated.

In recent years, development of so-called ‘in-cell’ touch-sensing technique (hereinafter referred to as in-cell display device) without using a touch panel has been developed, in which the touch sensing function is provided in the liquid crystal cell or in the display device.

For the above-described display device, generally, a configuration provided with a color filter substrate and an array substrate is known. The color filter substrate is composed of a plurality of regularly-arranged colored layers, and the array substrate includes active elements such as TFT (Thin Film Transistor) disposed therein.

For the in-cell display device, an in-cell structure provided with a pair of touch sensing electrode group has been developed. The pair of touch sensing electrode group is provided in either the color filter substrate or the array substrate, or provided in both of the color filter substrate and the array substrate. According to this structure, by detecting a change in electrostatic capacitance produced between touch sensing electrode groups, a touch sensing functionality can be achieved to detect an input-position of a finger or a pointer or the like.

In the case where an organic film is used as a base material of a touch panel, expansion and contraction of the base material (e.g., thermal expansion coefficient) is large. Hence, it is difficult to align positions (i.e., alignment) between a red pixel pattern, a green pixel pattern and a blue pixel pattern and a black matrix pattern, which compose fine pixels each having a size of approximately 10 μm to 20 μm. Therefore, the organic film base material is difficult to use for high-definition color filter substrates. As a conventional type display device, for example, display devices disclosed in PTLs 1 to 3 are known.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a black electrode substrate includes a transparent substrate having a first surface which is a touch-sensing input surface and a second surface opposite to the first surface, the second surface having a display region in a rectangular shape in plan view and an outer region outside of the display region, a black wiring forming a black electrode pattern that defines pixel opening portions in the display region, and a transparent resin layer formed in the display region such that the transparent resin layer overlaps with the black electrode pattern and has the same rectangular shape as the display region in plan view. The black wiring has a laminated structure including a first black layer including carbon and positioned in the display region and the outer region, a first indium-containing layer positioned on the first black layer, a copper-containing layer positioned on the first indium-containing layer, a second indium-containing layer positioned on the copper-containing layer, and a second black layer positioned on the second indium-containing layer. The black wiring has a terminal portion formed such that the second indium-containing layer positioned in the outer region is exposed from the laminated structure.

According to another aspect of the present invention, a method of manufacturing a black electrode substrate includes preparing a transparent having a first surface which is a touch-sensing input surface and a second surface opposite to the first surface such that the second surface has a display region in a rectangular shape in plan view and an outer region outside of the display region, forming a black wiring having a black electrode pattern, forming a transparent resin layer in the display region such that the transparent resin layer has the same rectangular shape as the display region in plan view, and that the outer region is exposed, and forming a terminal portion of the black wiring on the outer region. The forming of the black wiring includes forming a first black film including carbon on the transparent substrate, forming a first indium-containing film on the first black film, forming a copper-containing film on the first indium-containing film, forming a second indium-containing film on the copper-containing film, forming a second black film including carbon on the second indium-containing film, forming a second black layer by patterning the second black film, and etching, with the second black layer as a mask, the first black film, the first indium-containing film, the copper-containing film, and the second indium-containing film such that the black electrode pattern is formed. The forming of the terminal portion includes removing a portion of the transparent resin layer in a thickness direction and the second black layer located in the outer region.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, with reference to the drawings, several embodiments of the present invention will be described as follows.

In the following description, the same reference signs are designated to elements having the same or substantially the same functions, and the description will be omitted or will be described as needed.

In each of the drawings, dimension and ratio of respective elements are appropriately made different from that of actual objects, in order to allow the respective elements to be recognized on the drawings.

In each of the embodiments, only characteristics portion will be described, and description will be omitted for portions in the display device according to the present invention which are not different from the elements in an ordinary display device. The embodiments will each be described by way of an example of a black electrode substrate or a liquid crystal display device provided with the black electrode substrate. The black electrode substrate according to embodiments of the present invention can be applied to a display device such as organic EL display device, instead of the liquid crystal display device.

First Embodiment

Hereinafter, with reference toFIGS. 1 to 3, a black electrode substrate100according to an embodiment of the present invention will be described.

FIG. 1illustrates a minimum configuration of a black electrode substrate according to the present embodiment. The black electrode substrate100is provided with a transparent substrate15, and a plurality of black wirings6provided on the transparent substrate15. The cross-sectional view ofFIG. 1illustrates that the plurality of black wirings6are disposed on the transparent substrate15. As shown in plan view ofFIG. 3, the black wiring6configures a black electrode pattern60having a plurality of pixel opening portions8. In other words, regions formed between the plurality of black wirings6shown inFIG. 1correspond to the pixel opening portion8. A display portion, a shape of the opening, the number of pixels of the display device, which will be described later in detail, are not limited to the above-mentioned configurations.

As shown inFIG. 1, the transparent substrate15includes a first surface15aserving as a touch-sensing input surface, and a second surface15blocated on an opposite side of the first surface15a. As shown inFIG. 2B, the transparent substrate15includes a display region15c(reference sign D shown inFIG. 3) defined on the second surface15b, having a rectangular shape in plan view, and an outer region15ddefined on the second surface15band located at outer side of the display region15c. In other words, the outer region15dhas a frame shape surrounding the display region15c. The display region15cis a region for a display portion which configures the display device. The outer region15dis a region for a frame portion which configures the display device. As a material for the transparent substrate15, a glass substrate represented by non-alkali glass is used. As a material for the transparent substrate15, a resin film having high elasticity is not used. The thickness of the transparent substrate14ranges, for example, from 0.1 mm to 1 mm.

As shown inFIG. 2A, the black wiring6is composed of a first black layer1, a first indium-containing layer2, a copper-containing layer3formed of a copper layer or a copper-alloy layer, a second indium-containing layer4, and a second black layer5, which are formed on the transparent substrate15in this order.

The first black layer1is disposed on the second surface15band located in the display region15cand the outer region15d. The first indium-containing layer2is disposed on the first black layer1. The copper-containing layer3is disposed on the first indium-containing layer2. The second indium-containing layer4is disposed on the copper-containing layer3. The second black layer5is disposed on the second indium-containing layer4. In other words, the black wiring6has a laminated structure composed of the first black layer1, the first indium-containing layer2, the copper-containing layer3, the second indium-containing layer4, and the second black layer5.

FIG. 3is a partial plan view showing the black electrode substrate100according to the embodiment of the present invention. The cross section taken along the line A-A′ ofFIG. 3is shown inFIG. 1.

As shown inFIG. 3, the black electrode substrate100according to the present embodiment includes the black electrode pattern60formed on the second surface15b, defined by the black wiring6extending in a X-direction (first direction) and a Y-direction (second direction perpendicular to the first direction). A plurality of black electrode patterns60are formed on the second surface15b. Each of the black electrode patterns60has a plurality of pixel opening portions8(opening pattern) in a rectangular shape extending in the Y-direction, formed on the display region15cand surrounded by the black wiring6. In other words, in the black electrode pattern60, the black wirings6extend in the X-direction and the Y-direction, and the black wiring6extending in the X-direction and the black wiring6extending in the Y-direction are connected at connecting portions so as to form a matrix pattern (lattice pattern). In this configuration, the black wirings6each extending in the X-direction and the Y-direction are electrically connected to each other, to form a connection structure having a lattice pattern, thereby improving the strength. As shown inFIG. 3, 6 pixel openings are arranged in the X-direction and 480 pixel openings are arranged in the Y-direction in a single electrode pattern60.

It should be noted that two mutually adjacent black electrode patterns60(e.g., first black electrode pattern60aand second electrode pattern60b) are electrically isolated by a slit S. The pixel opening portions8are also provided between two electrically isolated black electrode patterns60. Even in this case, according to an embodiment of the present invention, the pixel opening portions8are defined by the black wiring6. Further, each black electrode pattern60has a terminal portion11provided in the outer region15d. A lead wire is provided between a conductive portion of the black electrode pattern60formed on the display region15cand the terminal portion11disposed in the outer region15d. In the terminal portion11, the second indium-containing layer4is exposed by removing the second black layer5which forms a laminated structure of the black wiring6.

The black electrode patterns60having the above-mentioned patterns are arranged along the X-direction to be in parallel to each other. The number of black electrode patterns60is, for example, 320 pcs. Therefore, the total number of pixels in the black electrode substrate100shown inFIG. 3is 1920×480. In the example shown inFIG. 3, the first black layer1and the second black layer5are formed to have the same pattern shape and the same line width. However, the line widths of the first black layer1and the second black layer5may be different, and the pattern shape may be different between the first black layer1and the second black layer5.

According to the present embodiment, each of the black electrode patterns60is defined by the black wiring6such that 6 pixel openings8are arranged in the X-direction, and one black electrode pattern60forms one black touch sensing electrode. However, the present invention is not limited to this configuration. A plurality of black wirings6may be formed on the transparent substrate15to be arranged in parallel to the X-direction, and a wiring group (e.g., grouping with which 6 wirings form a wiring group) may define the plurality of black wirings6. In this case, one wiring group may form one black touch sensing electrode.

Also, in the case where the black touch sensing electrode is formed by the wiring group, it is not necessary to use all of the black wirings that configure the wiring groups as drive electrodes (i.e., electrodes that generate a touch signal). For example, in a structure of a plurality of black wirings arranged in the X-direction, 6 black wirings are defined as one group and a plurality of black wiring groups is formed on the transparent substrate15. Further, black wiring arranged on every sixth wiring may be used as a drive electrode. Specifically, a drive method can be used in which 5 black wirings are thinned out (removed) from 6 black wirings, and a scan signal may be sent to the one black wiring, thereby driving (scanning) the black wiring. In this case, removed (thinned-out) 5 black wirings are in a state of electrically floating.

The first black layer1and the second black layer5contain carbon as a major color material (i.e., black color material). The first black layer1and the second black layer5are made of resin in which the black color material is dispersed. In the following description, the first black layer1and the second black layer5are sometimes simply referred to as a black layer. Only the provision of copper oxide or copper-alloy oxide on the transparent substrate15cannot achieve sufficient black or low reflectance properties. However, by providing the black layer on the transparent substrate15, the reflectance of visible light on a surface of the black wiring6can be reduced to 3% or less. Further, as will be described later, since the first black layer and the second black layer5are provided to sandwich the copper-containing layer3, high light-shielding properties can be obtained.

As a black color material, carbon, carbon nanotubes, or a mixture of a plurality of organic pigments and carbon can be used. For example, 51 mass % or more carbon is used as a major color material, and blue or red organic pigments can be added to the above-mentioned color material so as to adjust the reflected color. For example, by adjusting a carbon density (lower carbon density) contained in a photo-sensitive black coating liquid used as a starting material, reproducibility of color expressed in the black layer can be improved. According to the present embodiment, the carbon density is in a range from 4 to 50 mass % relative to the entire solid content including resin or curing agent and pigments. The carbon density may exceed 50 mass %. However, when the carbon density exceeds 50 mass % relative to the entire solid content, the suitability of the coating film is likely to be lowered. When the carbon density is 4 mass % or less, sufficient black color cannot be obtained so that reflection may occur due to a metal layer (copper-containing layer3) disposed under the black layer, thereby significantly lowering the visibility. In the following embodiments, when the carbon density is not mentioned, the carbon density is 40 mass % relative to the entire solid contents. Since the carbon density is thus determined, even when a large exposure apparatus is used, black wiring having thin line, for example, 1 μm to 5 μm line width can be formed by patterning.

When the black layer is formed, an alignment mark is formed on the transparent substrate15using the same material of the black layer. The alignment mark is used for an exposure step or aligning the patterns during photolithography process as a post-process. In the case where a process using the alignment mark is prioritized, an optical density of the black layer can be set, for example, to 2 or less in a transmittance measurement. The second black layer5may be formed by using a mixture of a plurality of pigments as a black color material without using carbon. For the reflectance of the first black layer1and the second black layer5, taking the refractive index (approximately 1.5) of the base material of a glass or a transparent resin into consideration, it is preferable to adjust content or type of the black color material, and content, type or film thickness of the resin to be used. When the condition for forming the black layer is optimized, the reflectance at the boundary surface between the base material, such as glass, of which the refractive index is approximately 1.5 and the black layer can be set to 2% or less within a wavelength range of visible light. The refractive index of the black layer is preferably 3% or less considering the visibility for the observer. It should be noted that refractive indexes of an acrylic resin used for a color filter, and liquid crystal material are approximately within a range from 1.5 to 1.7.

The total thickness of the black wiring6composed of the first black layer1, the first indium-containing layer2, a copper-containing layer3containing copper or copper-alloy, a second indium-containing layer4, and a second black layer5can be 1 μm or less. In the case where the thickness of the black wiring6exceeds 2 μm or more, uneven shape caused by a formation of the black wiring6may cause adverse effect to the liquid crystal alignment. Accordingly, the thickness of the black wiring6is preferably set to 1.5 μm or less.

In the display region15c, a plurality of pixel opening portions8are formed being surrounded by black wirings6(black layer) formed. The pixel opening portion8may be formed in a stripe shape, or may be formed in polygonal shape having at least two parallel sides. As a polygonal shape having two parallel sides, rectangle, hexagon, V-shape (doglegged shape) can be mentioned. The pattern shape of the black wiring can be electrically closed shape, as a frame shape surrounding the above-mentioned polygonal pixel. This pattern shape may be electrically closed in plan view or partially opened (partially disconnected in appearance). Depending on these shapes of patterns, electrical noise produced around the liquid crystal display device changes during the detection. In other words, depending on shape or area of the pattern in the copper-containing layer3as a metal layer, electrical noise produced around the liquid crystal display device changes during the detection.

The metal forming the copper-containing layer3is copper or copper alloy. In the case where the copper-containing layer3is formed using a thin copper film or a thin copper-alloy film, and if the thickness of the copper-containing layer3is set to 100 nm or more, or 150 nm or more, visible light hardly transmits through the copper-containing layer3. Accordingly, sufficient light-shielding properties can be obtained when the thickness of the copper-containing layer3is around from 100 nm to 300 nm for example, the copper-containing layer3forming the black wiring6of the present embodiment.

An alkali tolerant metal layer can be applied to the copper-containing layer3. Alkali tolerance is required for a development process using alkali development (post-process), for example. Specifically, in a process for forming a color filter, or a process for forming the second black layer5into a different pattern (black matrix) from the first black layer1, alkali tolerance is required for the copper-containing layer3. Alkali tolerance is required of the copper-containing layer3when the terminal portion is formed on the black wiring, which will be described later. Chrome has alkali tolerance and can be used as a metal layer which composes the black wiring6. However, since the resistance of chrome is high, toxic chrome ion is produced in the manufacturing process for forming a chrome layer. In this respect, considering actual production, it is difficult to apply chrome layer to the black wiring6. From a point view of low resistance, copper-containing layer3is preferably formed using copper or copper alloy. The copper or copper alloy is favorably used for a material of the copper-containing layer3because of good conductivity.

The copper-containing layer3may contain alloy element at 3 at % or less as a copper alloy. As an alloy element, one or more element can be selected from the group consisting of magnesium, calcium, titanium, molybdenum, indium, tin, zinc, aluminum, beryllium, nickel, scandium, yttrium and gallium. These alloy metals are added to the copper-containing layer3, whereby the pattern shape can be improved in a pattern formation during the photolithography process. Alloying copper (copper alloy) reduces diffusion of copper from the copper-containing layer3to a layer provided around the copper-containing layer3, so that heat resistance or the like can be improved. In the case where alloy element is added to the copper-containing layer3exceeding 3 at %, the resistance of the black wiring becomes high. By adding the alloy metals to the copper-containing layer3, the pattern shape can be improved in a pattern formation during the photolithography process. It is not preferable for the copper-containing layer3forming the black wiring6to have high resistance, because the drive voltage waveform in touch sensing may be distorted or a signal delay may occur.

The first indium-containing layer2and the second indium-containing layer4have two functions. The first function is to improve adhesive property/bonding property between the black layer and the copper-containing layer. The second function is to improve electrical connectivity between an electrode or a terminal and the copper-containing layer. The adhesion strength of copper, copper alloy, or metal oxide/nitride containing copper are generally low, relative to the black layer which is a dispersion of a resin and a black color material. Further, a peeling may occur at a boundary surface between the black layer and the oxide, or at a boundary surface between the black layer and the nitride. Moreover, generally, electrical connectivity is unstable for the copper, copper alloy, or the metal oxide/nitride containing copper, thereby lacking reliability. For example, the properties of copper oxide or copper sulfide which is formed with time on a copper surface are close to the properties of insulator. Thickness of these indium-containing layers may range from 2 nm to 50 nm, for example.

The first indium-containing layer2and the second indium-containing layer4(hereinafter will be simply referred to as indium-containing layer) are selected from conductive metal oxide containing indium, or copper indium alloy containing metal indium at 0.5 at % to 40 at % relative to the copper (alloy layer containing copper and indium). By increasing the content of indium-containing in the copper indium alloy, copper oxide which is likely to be formed on the surface of indium-containing layer can be minimized. Further, the indium-containing layer easily accomplishes electrical contact between a terminal or an electrode electrically connected to the copper-containing layer, and the copper-containing layer. When the copper indium alloy is used, metal indium may be contained at 40 at % or more in the indium alloy. Since the indium is costly, it is not preferable to have a high content of indium in the indium-containing layer because of economical reason. In the case where the content of the metal indium is 40 at % or less, since the indium-containing layer has heat resistance property up to 500° C., the indium-containing layer can be used as a metal wiring disposed in an array substrate. Since the atomic weight of indium is larger than that of copper, and the indium is likely to couple with oxygen compared to copper, the indium oxide rather than copper oxide is likely to be formed on the surface of the copper indium alloy. Use of the copper indium alloy can solve the problems including diffusion of copper when copper is singly used, and a formation of voids in the metal layer.

Usable conductive metal oxides containing indium include a mixed oxide so-called ITO (Indium Tin Oxide) containing indium oxide and tin oxide, a mixed oxide containing indium oxide, gallium oxide and zinc oxide, a mixed oxide containing tin oxide and antimony oxide, and a mixed oxide containing indium oxide, tin oxide and zinc oxide. The present invention is not limited to the above-described metal oxides, but the indium-containing layer may contain a mixed oxide containing small amount of other metal oxide added thereto, other metal oxide including titanium oxide, zirconium oxide, hafnium oxide, tungsten oxide and cerium oxide. In the case where the indium-containing layer contains a mixed oxide, ‘containing indium’ means that the content of indium oxide in the mixed oxide is from 51 wt % to 99 wt %, taking an electrical contact between the surface of the mixed oxide and the copper-containing layer3into consideration.

Even when indium is used as a metal, or indium is used as an oxide, adhesion strength of the indium-containing layer can be significantly improved with respect to a resin such as acrylic resin which is a base material of a color filer, a transparent substrate such as of glass, or an inorganic film made of silicon oxide, silicon nitride or the like. Therefore, an indium-containing layer can be provide at a boundary surface between a metal layer (i.e., copper-containing layer) formed of copper or copper alloy and a black layer, or at a boundary surface between the transparent substrate or an inorganic insulation layer and the metal layer. Even when indium is used as a metal, or indium is used as an oxide, by providing the indium-containing layer at the terminal portion, a terminal portion having good electrical connectivity can be provided.

The indium-containing layer can be formed by a method such as sputtering. When the indium-containing layer is formed, oxygen gas other than argon gas is introduced into a film-formation chamber during the sputtering to form the indium-containing layer.

(Function of Black Wiring)

As described above, the black electrode6(black electrode pattern60) is an electrically conductive wiring having a laminated structure in which the copper-containing layer3containing copper or copper alloy is sandwiched by two black layers, and the indium-containing layer is provided at a boundary surface between the copper-containing layer3and the black layer. The black wiring6which will be described in the following embodiment, can serve as a touch sensing electrode used for capacitive type touch sensing.

The touch sensing electrode has a configuration in which a plurality of detection electrodes are disposed in a first direction (e.g., X-direction) in plan view, and a plurality of drive electrodes are disposed in a second direction (Y-direction) via an insulation layer located in a lamination direction (Z-direction). For the drive electrodes, for example, an alternating current (AC) pulse signal having frequency of several KHz to several tens of KHz is applied to the drive electrodes. Normally, the AC pulse signal is thus applied so as to maintain a constant output waveform appearing at the detection electrode. When a finger or a pointer or the like contacts or approaches the first surface15awhich is the touch-sensing input surface, the output waveform of a detection electrode located at a contact portion or a proximity portion changes, whereby it is determined whether there is a touch input.

The black electrode pattern60(black wiring6) can be used as the above-described drive electrode or the detection electrode. According to a configuration in which a transparent conductive wiring7(described later) is provided in a direction (Y-direction) perpendicular to a direction (X-direction) where the black electrode pattern60is arranged, via an insulation layer of a transparent resin layer or the like, the transparent conductive wiring can be similarly used as a drive electrode or a detection electrode.

The line widths of the first black layer1and the second black layer5can be the same, but may be different from each other. The first black layer1pattern and the second black layer5pattern can be the same. It is preferable to design at least either a line width of the first black layer1or a line width of the second black layer5to be the same as the line width of the copper-containing layer3. For example, a plurality of black wirings can be arranged in one direction so as to form a stripe pattern, each of the black wirings being composed of the first black layer1, the first indium-containing layer2, the copper-containing layer3configured of a copper layer or a copper alloy layer, the second indium-containing layer4and the second black layer5. As described above, the transparent conductive wiring can be provided to orthogonally cross the arrangement composed of the plurality of black wirings.

In the case where the line widths between the first black layer1and the second black layer5which compose the black wiring6are the same, or pattern shapes of the first black layer1and the second black layer5are the same, the second black layer5is used as a patterning mask (i.e., resist pattern) to collectively perform wet etching for the indium-containing layer and the copper layer, thereby obtaining the first black layer1having a line width which is the same as the second black layer5. Thus, in the case where the line widths of the first black layer1and the second black layer5forming the black wiring6are the same, or the pattern shapes of the first black layer1and the second black layer5are the same, the black electrode substrate100can be manufactured with a simple manufacturing process. From the viewpoint of opening ratio of the pixel opening8, respective line widths in the black layer, the indium-containing layer and the copper-containing layer3preferably are the same. Herein, the same line width refers to that respective line widths of the black layer, the indium-containing layer and the copper-containing layer3are produced, in the known photolithography process including a exposure step, a development step and an etching step, with a width of ±1.5 μm with respect to the target line width.

The black wiring6has a configuration having low reflection properties to the visible light, in which the indium-containing layer and the copper-containing layer are sandwiched by the black layers. Hence, the black wiring6does not disturb the visibility to the observer. Also, when the black electrode substrate100is provided in a liquid crystal display device, light emitted from the backlight of the display device is not reflected by the copper-containing layer3, and hence light is prevented from being incident on the active element of TFT or the like.

The display device provided with a black electrode substrate according to the first embodiment uses LED light emission elements that emits red light, green light and blue light or the like, as a light source, thereby performing a color display with a field sequential method.

Second Embodiment

FIG. 4is a cross-sectional view showing a part of black electrode substrate according to the second embodiment, and showing a structure in which a red layer, a green layer and a blue layer are provided on the pixel opening portions.

In the pixel opening portion8, a color filter can be laminated to partially overlap an end portion of the second black layer5. The color filter is composed of colored layers such as a red layer R, a green layer G, and a blue layer B. Further, a transparent resin layer9is formed to cover the red layer R, the green layer G, and the blue layer B. To the color filter, other than colored layers of the red layer R, the green layer G and the blue layer B, other color layers can be added, including a light color layer, a complementary color layer, a white layer (transparent layer). Prior to laminating the color filter corresponding to the pixel opening portion8, the transparent resin layer may be formed on the second surface15bof the transparent substrate15, on which the black wiring6has been formed, so as to cover the black wiring6.FIG. 4exemplifies a configuration in which the transparent resin layer9is laminated on the colored layer of the red layer R, the green layer G, and the blue layer B. A thin film of electrically conductive layer (not shown) such as of ITO may be formed on the transparent resin layer9. In the following embodiments, a configuration in which the transparent conductive wiring is laminated on the color filter will be described.

The colored layer such as the red layer R, the green layer G, and the blue layer B are formed, for example, by dispersing an organic pigment into the photosensitive transparent resin, and forming the transparent resin, where the organic pigment is dispersed, on the color filter, followed by processing using a known photolithography method.

Third Embodiment

(Vertical Electric Field Type Liquid Crystal Display Device)

Next, with reference toFIGS. 5 to 10, a liquid crystal display device according to a third embodiment of the present invention will be described. In the third embodiment, the same reference signs are designated to the same elements as the first and second embodiments, and the description is omitted or simplified.

FIG. 5is a block diagram for explaining functions of the liquid crystal display device according to the present embodiment. A liquid crystal display device500according to the present embodiment is provided with a display unit110, a control unit120for controlling the display unit110and a touch sensing function. The control unit120having a publicly known configurations is provided with a video signal timing control unit121, a touch sensing/scan signal control unit122and a system control unit123.

The video signal timing control unit121controls a plurality of transparent conductive wirings7(described later) to be constant voltage, and transmits a signal to a signal line41(described later) of the array substrate200and a scanning line42(described later). A liquid crystal display voltage for display is applied to a pixel electrode24(described later) between the transparent conductive layer7and the pixel electrode24(described later), in a lamination direction Z, thereby performing a liquid crystal driving which drives liquid crystal molecules in a liquid crystal layer20(described later). Thus, images are displayed on the array substrate200.

The touch sensing/scan signal control unit122controls the transparent conductive wirings7, applies a detection drive voltage to the black electrode pattern60(black wiring6), and detects a change in an electrostatic capacitance between the black electrode pattern60and the transparent conductive wiring7(fringe capacitance), so as to perform touch sensing. The system control unit123controls the video signal timing control unit121and the touch sensing/scan signal control unit122.

FIGS. 6 and 9Aare cross sections each showing a part of the liquid crystal display device according to the present embodiment. The liquid crystal display device is provided with a known optical film such as a polarizing plate, an alignment film, a cover glass (protection glass) and the like. However, these components are omitted inFIGS. 6 and 9A.FIG. 9Ais a schematic view showing a cross section taken along E-E line ofFIG. 8and a cross section at an end portion of the liquid crystal display device. To make understanding of the embodiment easier, a cross section of the liquid crystal display device is schematically illustrated inFIG. 9A. However, a positional relationship between the pixel portion (pixel electrode) and the conductive portion inFIG. 9Adiffers from that of the real structure.

In the display device500(hereinafter referred to as liquid crystal display device500) according to the third embodiment, the black electrode substrate100according to the first embodiment of the present invention is used.

The liquid crystal display device500is provided with the black electrode substrate100, the array substrate200, and the liquid crystal layer20sandwiched between the substrates100and200, so as to form a liquid crystal cell.

The first surface15aof the black electrode substrate100serving as a touch sensing input surface is located at a front surface side of the liquid crystal display device500to form a display surface.

The liquid crystal layer20is used for a liquid crystal drive method using VA method (Vertically Alignment method: vertical electric field method using liquid crystal molecules of vertical alignment) in which the initial alignment direction of the liquid crystal is perpendicular to respective surfaces of the black electrode substrate100and the array substrate200. In the VA method, the liquid crystal layer20operates in response to voltage applied in the thickness direction Z (vertical direction), and the liquid crystal display device500displays video images or the like.

The liquid crystal drive method applicable to the vertical field type method can be appropriately selected from HAN (Hybrid-aligned Nematic), TN (Twisted Nematic), OCB (Optically Compensated Bend), CPA (Continuous Pinwheel Alignment), ECB (Electrically Controlled Birefringence), TBA (Transverse Bent Alignment) and the like.

As a driving method of the liquid crystal layer20, a liquid crystal drive method may be a common inversion drive method, or a method in which the pixel electrode is inversion-driven while the common electrode is driven at a constant voltage, thereby applying voltage to the liquid crystal layer20so as to drive the liquid crystal layer20.

Next, a transparent conductive wiring provided in the liquid crystal display device500will be described.

In addition to the structure of the black electrode substrate100described in the first and second embodiments, a transparent conductive wiring7is provided on the transparent resin layer9of the black electrode substrate100. The transparent conductive wiring7is used as both of a function of the touch sensing and a function of a common electrode (drive electrode of liquid crystal).

In the liquid crystal display device500, the liquid crystal layer is driven by applying a voltage between the transparent conductive wiring7as a common electrode and the pixel electrode24(described later) included in the array substrate200.

As shown inFIG. 6, the black wirings6of the black electrode substrate100are arranged along the X-direction in a stripe pattern extending in the Y-direction perpendicular to the paper surface. Similarly, the black electrode patterns60composed of the black wirings6are also arranged in the X-direction (SeeFIG. 3). A plurality of transparent conductive wirings7are arranged on the transparent resin layer9of the black electrode substrate100. The transparent conductive wirings7are arranged in the Y-direction in a stripe pattern extending in the X-direction. The black wiring6and the transparent conductive wiring7are arranged orthogonally crossing each other via the transparent resin layer9which is dielectric.

FIG. 7is plan view showing the black electrode substrate100shown inFIG. 6, as viewed from the film-surface of the transparent conductive electrode7, and showing an example of the black electrode substrate100. The Y-direction along which the black electrode pattern60composed of the black wiring6extends and the X-direction along which the transparent conductive layer7extends are orthogonally crossed each other, and the transparent conductive wiring7having large width in the Y-direction and the plurality of black wirings6are arranged being overlapped each other. For example, the pixel pitch in the X-direction is set to 21 μm, the line width of the black wiring6is set to 4 μm, and the line width of the transparent conductive wiring7is set to 123 μm (pitch of the transparent conductive layer7is set to 126 μm). InFIG. 7, when focused on one black electrode pattern60, one transparent conductive wiring7and six black wirings6are orthogonally crossed each other. Adjacent black electrode patterns60are electrically separated by the slit S. The width of the slit S can be 1 μm to 4 μm

In a configuration in which the black electrode substrate100is integrated to the liquid crystal display device500, a metal wiring provided in the array substrate is located below the slit S, whereby light leakage from the liquid crystal display device can be avoided. Although not shown, the red layer R and the blue layer B are formed being overlapped each other (color overlapping) in a portion where the slit S is provided in the present embodiment, to thereby suppress the light leakage produced from the liquid crystal display device500. Respective black wirings6having a thin line width is capable of forming fringe capacitance along the direction in which the wirings are extended, so that high S/N ratio can be produced by large fringe capacitance.

For example, according to the present embodiment, the transparent conductive wiring7is a common electrode and serves as a detection electrode which composes a touch sensing electrode. The black electrode pattern60provided with the black wiring6serves as a drive electrode composing the touch sensing electrode. Substantially constant electrostatic capacitance C5is formed between the black electrode pattern60and the transparent conductive layer7(seeFIG. 6). In the case where a finger or a pointer or the like contacts or approaches the black electrode substrate100, electrostatic capacitance changes at a portion corresponding to the location of the finger or the pointer or the like, thereby detecting the touch-input location.

The present embodiment employs a configuration of detecting a change in the electrostatic capacitance produced between the black electrode pattern60having a group composing a plurality of black wirings6and the transparent conductive wiring7. However, the present invention is not limited to this configuration. The above-described configuration using the black electrode pattern40may not be used. However, a plurality of individual black wiring can be provided on the black electrode substrate100. In this case, for example, a drive method can be used in which 5 black wirings are thinned out from 6 black wirings (removed), and a scan signal is sent to the one black wiring, thereby driving (scanning) the black wiring being thinned out. As a result, a high speed touch sensing can be accomplished.

The transparent conductive wiring7is designed to have constant voltage for both the touch sensing driving and liquid crystal driving. Thus, by designing the voltage of the transparent conductive wiring7in this way, the touch sensing and the liquid crystal driving can be driven at different frequencies. According to the liquid crystal display device500, large fringe capacitance is achieved and power consumption can be reduced by lowering required drive voltage of the touch sensing drive, while high S/N ratio is maintained.

Next, with reference toFIGS. 6, 8, 9 and 10, the array substrate200provided in the liquid crystal display device500will be described. As shown inFIG. 6, the array substrate200is provided with a transparent substrate25, the insulation layers33,34, and35disposed successively on the transparent substrate25, and the pixel electrode24provided on the insulation layer35. The pixel electrode24is electrically connected to an active element26(thin film transistor) via a contact hole27(seeFIG. 9A). Each of the active elements26is disposed adjacent to the corresponding one of the plurality of pixel opening portions8. Further, as shown inFIG. 9A, the array substrate200includes a first metal wiring29disposed at a seal portion32or the like of the liquid crystal display device500. The first metal wiring29is formed together with a gate electrode28(described later) using the same process and the same material. The liquid crystal layer20is sealed on the inner side of the seal portion32and between the transparent conductive wiring7and the pixel electrode24. The first metal wiring29may have a laminated structure in which a copper-containing layer and two indium-containing layers are laminated, the copper-containing layer containing at least copper and being sandwiched by the two indium-containing layers each containing indium.

FIG. 8is an enlarged plan view of a pixel in the array substrate200.

The array substrate200includes, on a major surface of the transparent substrate25which faces the liquid crystal layer20, a plurality of pixel electrodes24, a plurality of thin film transistors26, a second metal wiring40and a plurality of insulation layers33,34and35. More specifically, the plurality of pixel electrodes24and the plurality of thin film transistors26are provided on the major surface of the transparent substrate25via the insulation layers33,34and35. InFIG. 6, only the thin film transistor6is not illustrated. InFIG. 8, the insulation layers33,34, and35are not illustrated.

The second metal layer40has a plurality of signal lines41(source line, source electrode), scanning lines42(gate line) and auxiliary capacitance lines43. Each scanning line42is connected to the gate electrode28. The signal line41, the scanning line42and the auxiliary capacitance line43have the same wiring structure as the black wiring6. Thus, the source electrode and the drain electrode which compose the active element26are formed of the second metal wiring40having three layered structure of the indium-containing layer/copper/indium-containing layer. In other words, the second metal wiring40has a laminated structure in which a copper-containing layer and two indium-containing layers are laminated, the copper-containing layer containing at least copper and being sandwiched by the two indium-containing layers each containing indium. The second metal wiring40is formed on the insulation layer35on the first metal wiring29. The second metal wiring is formed into a film by a manufacturing process different from that of the first metal wiring29.

Each of the pixel electrodes24has a known configuration, being provided on the surface of the insulation layer35facing the liquid crystal layer20, and being disposed to face the pixel opening portion8surrounded by the black wiring6.

A channel layer46of each thin film transistor26can be formed by a silicon semiconductor such as poly-silicon or the like, or an oxide semiconductor. The thin film transistor26preferably includes the channel layer46which is formed of an oxide semiconductor, such as IGZO (registered trade mark), containing two or more metal oxides selected from gallium, indium, zinc, tin and germanium. That is, the channel layer46is formed of InGaZnO-group metal oxide. The thin film transistor26having such a structure has high memory properties (less leak current), whereby the pixel capacitance after application of liquid crystal display voltage can be held easily. As a result, the auxiliary capacitance line43can be omitted from the configuration.

The thin film transistor including an oxide semiconductor as a channel layer has a bottom-gate type structure, for example. For the thin film transistor, a transistor structure such as a top gate type, or a double gate type may be used. The thin film transistor having a channel layer of the oxide semiconductor can be used for an optical sensor or other active elements.

The thin film transistor26in which the oxide semiconductor such as IGZO is used for the channel layer46has high electron mobility of applying a required drive voltage to the pixel electrode24in a short period of time, e.g., 2 msec (millisecond) or less. For example, in the case of double speed drive (the number of display frames per second is 120 frames), one frame corresponds to about 8.3 msec. Hence, for example, 6 msec can be allocated to the touch sensing operation. Since the transparent conductive wiring7serving as a drive electrode is at a constant voltage, the liquid crystal driving and the touch electrode driving do not have to be conducted in a time-sharing manner. The driving frequency of the pixel electrode for driving the liquid crystal, and the drive frequency of the touch electrode can be different from each other.

Also, since the thin film transistor26where the oxide semiconductor is used for the channel layer46has only small leak current as described above, the drive voltage applied to the pixel electrode24can be retained for a long period of time. The signal line, the scanning line, the auxiliary line or the like of the active element are formed with copper wiring having low wiring resistance, and the active element uses IGZO which can be driven in a short period of time, whereby a time margin can be extended in scanning operation of the touch sensing. Hence, a change in the electrostatic capacitance can be detected accurately. The oxide semiconductor such as IGZO is used for the active element so that a driving time of the liquid crystal or the like can be shortened, thereby producing a sufficient time for the touch sending operation during the video signal processing of the entire display screen.

The drain electrode36extends to the center portion of the pixel from the thin film transistor26, and connected to the pixel electrode24as a transparent electrode via the contact hole27. The source electrode55extends from the thin film transistor26so as to be electrically connected to the signal line41.

FIG. 9Ais a diagram illustrating an outer peripheral structure of the liquid crystal display device500according to the present embodiment.FIG. 9Aillustrates an example of an electrical connection between the transparent conductive wiring7and the array substrate200. The transparent conductive wiring7is included in the black electrode substrate100provided with the black touch sensing electrode (i.e., black electrode pattern60). The transparent conductive wiring7included in the black electrode substrate100is formed to cover a plane of the transparent resin layer9located in the display region15cand to cover an end portion of the transparent resin layer9located in the outer region15d. Moreover, the transparent conductive wiring7is formed covering an inclined surface formed in the end portion of the transparent resin layer9, and a joint portion between the end portion of the transparent resin layer9and the second surface15bof the black electrode substrate100, and extending towards the outside of the liquid crystal cell. In the outer region15d, the transparent conductive wiring7formed on the black electrode substrate100configures the terminal portion13. In the outer region15d, the seal portion32and a conductive portion31are formed, covering the terminal portion13. The terminal portion13is connected to the first metal wiring29of the array substrate200via the conductive portion31. The first metal wiring29can be formed within the same layer as the gate electrode28or the gate line. The first metal wiring29electrically connected to the transparent conductive wiring7via the conductive portion31is maintained at a constant voltage.

FIG. 9Bis an enlarged diagram illustrating a portion designated by a reference sign M inFIG. 9A. The first metal wiring29provided on the transparent substrate25has a three-layer structure, similar to the configuration of the black wiring7described in the first embodiment, including the first indium-containing layer2, the copper-containing layer3and the second indium-containing layer4. According to the present embodiment, the first indium-containing layer2having a thickness of 20 nm is formed using ITO (In—Sn—O). The copper-containing layer3having a thickness of 200 nm is formed by using a copper magnesium alloy containing 0.5 at % magnesium (Mg). The second indium-containing layer4having a thickness of 20 nm is formed by using a copper magnesium alloy containing 22 at % indium. ITO is formed into a film using sputtering method under the room temperature condition to form amorphous, thereby forming the first indium-containing layer2. The first indium-containing layer2, the copper-containing layer3, and the second indium-containing layer4can be readily and collectively processed by wet etching. Reflection color of the surface of the copper indium alloy is nearly gray so that red coloration due to single use of copper can be avoided and also reflectance can be lowered.

The first metal layer29according to the present embodiment is formed such that copper or copper alloy (copper-containing layer3) is sandwiched by the indium-containing layers, so that the adhesion strength with the transparent substrate such glass can be improved. Further, electrical connection on the first metal layer29becomes stable so as to achieve good terminal structure. According to the present embodiment, the black electrode pattern60extends in the Y-direction and the transparent conductive wiring7extends in the X-direction. The present invention is not limited to such a structure, but the black electrode pattern60may extend in the X-direction and the transparent conductive wiring7may extend in the Y-direction.

In such a configuration, the indium-containing layer is sandwiched between the transparent conductive wiring7and the conductive portion31. In this case, the indium-containing layer enhances electrical connectivity between the transparent conductive wiring7and the conductive portion31. Accordingly, electrical contact can readily be made between the first metal wiring29and the transparent conductive wiring7.

FIG. 10is a diagram showing an outer peripheral structure of the liquid crystal cell in the liquid crystal display device according to the present embodiment.FIG. 10illustrates a cross section taken along line B-B′ ofFIG. 7and an example of electrical connection between the black electrode pattern60of the black electrode substrate100and the array substrate200. In a manufacturing process of forming the blue layer B in the pixel opening portion8shown inFIG. 7, the blue layer B may be formed not only in the pixel opening portion8, but also outside the pixel opening portion8(region where the pixel opening portion8is not formed), such that the blue layer B is located on the black electrode pattern60which extends towards the outer region15dfrom the display region15c. Considering this situation,FIG. 10shows a configuration where the blue layer B is provided between the transparent resin layer9and the black electrode pattern60.

In the outer region15d, the second indium-containing layer4of the black electrode pattern60is exposed. In the display region15c, the second black layer5is covered by the transparent resin layer9. In particular, in a laminated structure of the black electrode pattern60provided in the outer region15d, the second black layer5is removed by etching which will be described later, and the second indium-containing layer4is exposed so as to form the terminal portion11. The terminal portion11is connected to the first metal wiring29provided on the transparent substrate2(i.e., array substrate200) via the conductive portion31. The structure of the first metal wiring29and the structure of the conductive portion31are similar to those ofFIG. 9A. A driving voltage is supplied to the first metal wiring29electrically connected to the black electrode pattern60via the conductive portion31, the driving voltage being a voltage related to touch sensing driving and relatively supplied to the transparent conductive wiring7having the constant voltage.

According to this configuration, the second indium-containing layer4of the black electrode pattern60is sandwiched between the copper-containing layer3and the conductive portion31. In this case, the second indium-containing layer4enhances electric connectivity between the copper-containing layer3and the conductive portion31. Accordingly, electrical contact between the first metal wiring29and the copper-containing layer3can readily be accomplished.

In the liquid crystal display device500having the above-described configuration, the control unit120controls the liquid crystal driving and the touch sensing driving. When the touch sensing operation is performed, the black electrode pattern60is permitted to serve as a drive electrode and the transparent conductive wiring7is permitted to serve as a detection electrode having a constant voltage, to thereby differentiate a drive condition of the touch sensing and a drive condition (e.g., frequency or voltage) of the liquid crystal layer20. Since frequencies for driving the touch sensing and the liquid crystal driving are different from each other, the touch sensing driving and the liquid crystal driving are unlikely to influence from each other. For example, a driving frequency of the touch sensing can be within a range from several KHz to several tens of KHz, and the driving frequency of the liquid crystal can be within a range from 60 Hz to 240 Hz. Further, the touch sensing driving and the liquid crystal driving can be performed in a time-sharing manner. In the case where the black electrode wiring6is used as a drive electrode (touch sensing drive scanning electrode), scanning frequency for detecting the electrostatic capacitance can be adjusted as desired, depending on a required speed of the touch input. Alternatively, in the touch sensing driving, the transparent conductive wiring7may be permitted to serve as a drive electrode, and the black electrode pattern60may be served as a detection electrode. In this case, the transparent conductive wiring7serves as a drive electrode (scanning electrode) to which voltage having constant frequency is applied. In the touch sensing driving and the liquid crystal driving, voltage (alternating current (AC) signal) may be applied to the drive electrode with an inverting driving method in which positive and negative voltages are inverted. The touch sensing operation and the liquid crystal driving may be or may not be performed in a time-sharing manner.

In applying the touch sensing drive voltage, voltage amplitude (peak to peak) of the AC signal to be applied may be decreased to reduce the influence of the touch sensing drive voltage to the liquid crystal display.

According to the liquid crystal display device500of the present embodiment, the black wiring6included in the black electrode pattern60has a laminated structure composed of the first black layer1, the first indium-containing layer2, the copper-containing layer3, the second indium-containing layer4and the second black layer5. Therefore, adhesion strength between the first black layer1and the copper-containing layer3can be improved by the first indium-containing layer2, and adhesion strength between the copper-containing layer3and the second black layer5can be improved by the second indium-containing layer4. Accordingly, the copper-containing layer3is prevented from being peeled off from the first black layer1, and the second black layer5is prevented from being peeled off from the copper-containing layer3. Further, since the copper-containing layer3is sandwiched by the first indium-containing layer2and the second indium-containing layer4, electrical connectivity between an electrode or a terminal connected to the copper-containing layer3, and the copper-containing layer3can be improved. In particular, the second indium-containing layer4laminated on the copper-containing layer3is exposed from the terminal portion11, whereby electrical connectivity between the conductive portion31and the copper-containing layer3can be improved.

Furthermore, in the black electrode pattern60, the black wiring6extends in the X-direction and the Y-direction, and the black wiring6extending in the X-direction and the black wiring6extending in the Y-direction6are connected to form a lattice pattern. Hence, when pressing force is applied to the first surface15aas a touch sensing input surface, force propagated to the black wiring6is divided, along the lattice pattern, into the X-direction and the Y-direction which are extending direction of the black wiring6. Thus, since the black wiring6has a two-dimensional lattice pattern, strength against the pressing force applied to the first surface15ais enhanced. As a result, high adhesion strength is obtained to prevent peeling of the copper-containing layer3from the first black layer1and the second black layer5, and also the black wiring6having high mechanical strength is accomplished, in a view point of stress dispersion. In other words, since the black wiring6has a two-dimensional lattice pattern, an effect of preventing peeling of the copper-containing layer3from the first black layer1and the second black layer5can be synergistically obtained.

Further, to serve as a touch-sensing input surface, the first surface15aof the black electrode substrate100is located on a front surface side of the liquid crystal display device500to form a display surface. Therefore, when the liquid crystal display device500is used, pressing force is applied to the first surface15awith the user's touch input. Due to occurrence of the pressing force, a stress occurs in the transparent substrate15. The stress is propagated in the transparent substrate15towards the second surface15bfrom the first surface, and then reaches the second surface15b. The force due to the stress propagating in the transparent substrate15is applied to the black wiring6provided in the second surface15b.

Moreover, when the user does not use the liquid crystal display device500, for example, the liquid crystal display device500is often put in a pocket of the user's clothes or in a bag which the user carries. In this case, unintentional external force may be applied to the first surface15aof the black electrode substrate100. As a result, unintentional external force may be applied to the black wiring6. Further, the black electrode substrate may be bent. In other words, it is considered that the black electrode substrate100is most likely to be affected by the external force among the components configuring the liquid crystal display device500.

In contrast, even in a case where the liquid crystal display device500is exposed to the above-mentioned usage environment or storage environment, since the indium-containing layer improves the adhesion strength of the copper-containing layer3with the first black layer1and the second black layer5, the copper-containing layer3can be prevented from being peeled off. Further, the indium-containing layer can improve the electrical connectivity between the conductive portion31and the copper-containing layer3. Since high strength is obtained by the black wiring6having the two-dimensional lattice pattern, an effect of preventing peeling of the copper-containing layer3from the first black layer1and the second black layer5can be synergistically obtained. In other words, tolerance of the black electrode substrate100and the liquid crystal display device500against external force can be enhanced.

Fourth Embodiment

(Transverse Electric Field Type Liquid Crystal Display Device)

Next, with reference toFIG. 11, a liquid crystal display device according to a fourth embodiment of the present invention will be described. In the fourth embodiment, the same reference signs are applied to the same elements as the first to third embodiments, and the description is omitted or simplified.

As shown inFIG. 11, the liquid crystal display device600according to the present embodiment is provided with a black electrode substrate100, an array substrate300having active elements, and a liquid crystal layer620sandwiched between the substrates100and300to form a liquid crystal cell.

The first surface15aof the black electrode substrate100serving as a touch-sensing input surface is located at a front surface side of the liquid crystal display device600to form a display surface.

The array substrate300is provided with an active element (TFT) for driving a liquid crystal, a pixel electrode324for driving the liquid crystal, a common electrode332, an insulation layer disposed between the pixel electrode324and the common electrode332. The common electrode332serves as an electrode used for liquid crystal driving and a touch sensing electrode (i.e., touch sensing wiring).

The common electrode332extends in parallel to a gate line (i.e., metal wiring) that configures the active element.

In the initially aligned state, the liquid crystal layer620is aligned horizontally to the surface of the transparent substrate25. The liquid crystal driving is controlled by the active element, and the liquid crystal is driven by fringe field produced between the pixel electrode324and the common electrode332. This liquid crystal driving method is referred to as FFS (fringe field switching), or IPS (in-plane switching). The common electrode332has an opening having substantially the same width as the pixel opening portion8in plan view, and has a stripe shape extending in the X-direction perpendicular to a direction (Y-direction) along which the black electrode pattern60extends. For the touch sensing, an electrostatic capacitance C6which is substantially constant is formed between the black electrode pattern60and the common electrode332.

Unlike the third embodiment, the transparent conductive wiring7does not have to be formed in the black electrode substrate100. According to the configuration shown inFIG. 11, liquid crystal driving and the touch sensing driving with the common electrode332are performed in a time-sharing manner. The liquid crystal display driving and the touch sensing driving are controlled by the control unit120shown inFIG. 5. The common electrode332is formed of the transparent conductive film such as ITO.FIG. 11omits illustration of elements such as an active element for driving liquid crystal, an auxiliary capacitance, an alignment film, an optical film, or a cover glass.

According to the fourth embodiment, effects similar to the third embodiment can be obtained.

Fifth Embodiment

(Transverse Field Type Liquid Crystal Display Device)

Next, with reference toFIG. 12, a liquid crystal display device according to a fifth embodiment of the present invention will be described. In the fifth embodiment, the same reference signs are designated to the same elements as the first to fourth embodiments, and the description is omitted or simplified.

As shown inFIG. 12, the liquid crystal display device700according to the present embodiment is provided with a black electrode display substrate100, an array substrate400having active elements, and a liquid crystal layer720sandwiched between the substrates100and400to form a liquid crystal cell.

The first surface15aof the black electrode substrate100serving as a touch-sensing input surface is located at a front surface side of the liquid crystal display device700to form a display surface.

The array substrate400is provided with an active element (TFT) for driving a liquid crystal, a pixel electrode424for driving the liquid crystal, a common electrode432, a touch sensing wiring439, an insulation layer disposed between the pixel electrode424and the common electrode432, and an insulation layer disposed between the common electrode432and the touch sensing wiring439. The common electrode432serves as an electrode used for liquid crystal driving. The touch sensing wiring439extends in parallel to the gate wiring that configures the active element, serves as a touch sensing electrode used for the touch sensing driving, and has a stripe shape extending in the X-direction perpendicular to a direction (Y-direction) along which the black electrode pattern60extends. The touch sensing wiring439has a laminated structure in which a copper-containing layer and two indium-containing layers are laminated, the copper-containing layer containing at least copper and being sandwiched between the two indium-containing layers each containing indium.

In the initially aligned state, the liquid crystal layer720is aligned horizontally to the surface of the transparent substrate25. The liquid crystal driving is controlled by the active element, and the liquid crystal is driven by fringe field produced between the pixel electrode424and the common electrode432. This liquid crystal driving method is referred to as FFS (fringe field switching), or IPS (in plane switching). The common electrode432has an opening having substantially the same width as the pixel opening portion8in plan view. For the touch sensing, electrostatic capacitance C7which is substantially constant is formed between the black electrode pattern60and the touch sensing wiring439.

Unlike the third embodiment, the transparent conductive wiring7does not have to be formed in the black electrode substrate100. According to the configuration shown inFIG. 12, liquid crystal driving in the common electrode432, and driving of the touch sensing wiring439in the touch sensing do not have to be performed in a time-sharing manner. The frequency of the signal for driving the touch sensing wiring439and the frequency of the liquid crystal drive signal may be different from each other. The common electrode432is formed of a transparent conductive film such as ITO. The touch sensing wiring439is formed of the same metallic material as the gate line, with the same manufacturing process used for forming the gate line. The touch sensing wiring439and the metal wiring which configures the active element are electrically isolated from each other. The touch sensing wiring439can be used as a drive electrode or a detection electrode in the touch sensing function. The liquid crystal display driving and the touch sensing driving are controlled by the control unit120shown inFIG. 5.FIG. 12omits illustration of elements such as an active element for driving liquid crystal, an auxiliary capacitance, an alignment film, an optical film, or a cover glass.

According to the fifth embodiment, effects similar to the third embodiment can be obtained.

Sixth Embodiment

(Liquid Crystal Display Device Provided with Light Shielding Layer)

Next, with reference toFIGS. 13A to 13C, a liquid crystal display device according to a sixth embodiment of the present invention will be described. In the sixth embodiment, the same reference signs are applied to the same elements as the first to fifth embodiments, and the description is omitted or simplified.FIG. 13Ais plan view showing a part of an array substrate450included in the liquid crystal display device according to the embodiment of the present invention.FIG. 13Bis a partial cross sectional view take along the line C-C′ ofFIG. 13A.FIG. 13Cis a cross sectional view showing a part of the array substrate450included in the display device of the embodiment of the present invention.FIGS. 13A to 13Comit illustration of elements such as a common electrode for driving liquid crystal, an auxiliary capacitance, an alignment film, an optical film, or a cover glass.

As shown inFIG. 13C, a liquid crystal display device800according to the present embodiment is provided with a black electrode display substrate100, the array substrate450having active elements, and a liquid crystal layer820sandwiched between the substrates100and450to form a liquid crystal cell. The first surface15aof the black electrode substrate100serving as a touch-sensing input surface is located at a front surface side of the liquid crystal display device700to form a display surface.

As shown inFIGS. 13A and 13B, the array substrate450is provided with a gate line471extending in the X-direction, a gate electrode478connected to the gate line471, a source line475extending in the Y-direction, an active element476, a touch sensing electrode472(touch sensing wiring), and a light shielding layer473. As shown inFIG. 13C, the touch sensing electrode472is electrically isolated from the gate line471, and disposed in parallel to the gate line471so as to overlap with the gate line471via insulation layers483,484and485. The touch sensing electrode472and the light shielding layer473are formed in the same manufacturing process using the same metallic material, and positioned in the same layer.

The configuration of the touch sensing electrode472and the metallic material forming the touch sensing electrode472are not limited. For example, configurations or material forming these configurations can be exemplified, including metals having high melting points such as titanium or molybdenum, a single layer or a laminated layer configuration containing aluminum or aluminum alloy, three-layer configuration of titanium/copper/titanium, or three-layer configuration of indium-containing layer/copper alloy/indium-containing layer. Moreover, to improve display visibility, a black layer can be formed on the touch sensing electrode472. An insulation layer made of silicon oxide or silicon oxynitride may be formed on the touch sensing electrode472and the light shielding layer473. To reduce electrical noise, it is preferable to form the touch sensing electrode472in a simple shape such as stripe shape. However, to improve light shielding properties, a pattern shape in which the touch sensing electrode472and the light shielding layer473are connected can be used. In plan view, the touch sensing electrode472extending in the X-direction orthogonally crosses the black electrode pattern60which extends in the Y-direction. The touch sensing electrode472serves as a touch sensing electrode. In the touch sensing operation, as described in the above embodiment, thinned-out driving can be performed. Specifically, according to the configuration having a plurality of touch sensing electrodes472on the array substrate450, 6 touch sensing electrodes are defined as one group, and a plurality of touch sensing electrode groups are provided to the array substrate450. Then, 5 touch sensing electrodes are thinned out (removed) from the 6 electrodes, and a scan signal is transmitted to one touch sensing electrode. By this driving method, touch sensing electrode can be driven (scanned) with thinned-out touch sensing electrodes. In this case, removed (thinned out) 5 touch sensing electrodes are in an electrically floated state (i.e., floating).

As shown inFIG. 13B, the pixel electrode474which drives liquid crystal is electrically connected to the drain electrode included in the active element476, via a contact hole.

InFIGS. 13B and 13C, the pixel electrode474is connected to the drain electrode via the light shielding layer473. However, a structure to connect the light shielding layer473and the drain electrode is not limited to the structure shown in the present embodiment. The channel layer (semiconductor layer) in the active element476is covered by the light shielding layer473and shielded thereby.

During touch sensing operation, the electrostatic capacitance C8is produced between the black wiring6provided in the black electrode substrate100and the touch sensing electrode. For example, the touch sensing electrode472can serve as a drive electrode and the black electrode6can serve as a detection electrode. When a finger or a pointer contacts or approaches the first surface15awhich is a touch sensing input surface, electrostatic capacitance changes and the black electrode wiring6detects the change so as to determine whether there has been a touch input. It should be noted that the touch sensing electrode472can serve as a detection electrode and the black electrode can serve as a drive electrode.

The material used for forming the channel layer included in the active element476may be an oxide semiconductor or a poly silicon semiconductor.

According to the present embodiment, the light shielding layer473shields backlight or external light so that various active elements can be used for the liquid crystal display device800. The display device according to the embodiment of the present invention can be applied to HMDs (head mount displays) or liquid crystal projectors.

According to the sixth embodiment, effects similar to the third embodiment can be obtained.

Seventh Embodiment

Next, with reference toFIG. 3andFIGS. 14A to 15, a manufacturing method of a black electrode substrate according to a seventh embodiment of the present invention will be described.

FIGS. 14A to 14Care cross-sectional views partly showing a manufacturing method of the black electrode substrate according to the embodiment of the present invention.FIG. 15is a flowchart showing a manufacturing process of the black electrode substrate of the embodiment of the present invention. The manufacturing process according to the present embodiment includes forming the black electrode substrate described in the first embodiment, and further forming the transparent resin pattern is on the black electrode substrate. It should be noted that formation of the black electrode pattern60including the black wiring6can be followed by forming colored layer pattern on the pixel opening portion8to arrange a red layer, a green layer and a blue layer in the pixel opening portion8, and further forming a transparent resin layer.

First, as shown inFIG. 14A, a transparent substrate15is prepared. The transparent substrate15includes a first surface15aserving as a touch sensing input surface, a second surface15bopposite to the first surface15a, a display region15cdefined on the second surface15bhaving a rectangular shape in plan view, an outer region15ddefined on the second surface15band positioned outside the display region15c. The black electrode pattern60defined by the black wiring6is formed on the transparent substrate15.

With reference toFIG. 15, a forming method of the black electrode pattern60will be described.

First, a black coating liquid containing carbon as a major color material is coated on the transparent substrate15, followed by curing to form a first black overall film (Step S1). Thereafter, a first indium-containing overall film containing indium is formed on the first black overall film, followed by forming a copper-containing overall film containing copper on the first indium-containing overall film, which is further followed by forming a second indium-containing overall film containing indium on the copper-containing overall film (Step S2). Specifically, a laminate of the above-mentioned three overall films is laminated on the first black overall film by continuous film-formation, by using a vacuum film-forming apparatus. Next, a photosensitive black coating liquid capable of being alkali-developed (coating liquid containing carbon as a major color material) is used to form a second black overall film on the second black overall film (Step S3). As a black coating liquid, for example, acrylic photosensitive black coating liquid known as a black matrix material can be used. A color material used for the black layer composing the black electrode is preferably mainly a carbon. To adjust reflective color produced by the black layer, a small amount of organic pigment may be added to the photosensitive black coating liquid. However, most of organic pigments have a metal coordinated in the structure of the pigment. In the case where a film containing such a pigment is dry-etched, the coordinated metal may cause a contamination. Considering this, formulation of the photosensitive black coating liquid is adjusted.

Thereafter, with a known photolithography method, the second black overall film is exposed, developed and cured so as to form a second black layer5(Step S4). The patterned second black layer5has the same planar shape as the black electrode pattern60(a plurality of pixel opening portions8, black wiring6, terminal portion11, slit S, lead wire) shown inFIG. 3.

Next, the second black layer5having the above-described planar pattern is used as a mask to perform wet etching for the first black overall film, the first indium-containing overall film, the copper-containing overall film and the second indium-containing overall film (Step S5). Thus, the black electrode pattern60defined by the black wiring6is formed. The black electrode pattern60has a laminated structure composed of the first black layer1, the indium-containing layer2, the copper-containing layer3, the second indium-containing layer4and the second black layer5. The second black layer5, the first indium-containing layer2, the copper-containing layer3and the second indium-containing layer4have substantially the same pattern.

Next, as shown inFIG. 14B, a transparent resin overall film containing a transparent resin material is formed on the transparent substrate15so as to cover the second black layer5(Step S6). Further, the transparent resin overall film is patterned so as to form the transparent resin layer9having a rectangular shape of the same size as the display region15cin plan view (Step S7). In other words, the pattern of the transparent resin layer9is, as shown inFIG. 3, a pattern having a region exposed for forming the terminal portion11which is necessary for electrical mounting, and having substantially the same size as the display region15c.

Subsequently, a part of the transparent resin layer9in the thickness direction (i.e., Z-direction) (portion close to the surface of the transparent resin layer9) and the second black cooler layer5located onto the outer region15dare removed by dry etching using fluorocarbon-based gas (Step S8). In other words, a part of the transparent resin layer9and the second black layer5are simultaneously dry-etched. Thus, even when the second black layer5is removed, the transparent resin layer9remains with a predetermined thickness. Specifically, a partial etching of the transparent resin layer9in the display region15cand a complete etching of the second black layer5exposed to the outer region15dare simultaneously performed. Taking the dry etching into consideration, the transparent resin layer9before being dry-etched has relatively a large thickness. Hence, as shown inFIG. 14C, the terminal portion11is formed in the outer region15d, the terminal portion11having a surface Me where the second indium-containing layer4is exposed (Step S9).

In the process of removing a part of the transparent resin layer9and the second black layer5shown in the cross section view ofFIG. 14Cin the thickness direction, it is preferable to use a fluorocarbon-based gas such as CF4or C3F8as a dry-etching gas. By using such a gas, the second black layer5can be removed by etching, without giving a large influence on the indium-containing layer or the copper-containing layer3. It should be noted that argon or oxygen may be added to CF4or C3F8gas or the like as needed. Appropriate adjustments can be made to the pressure in the chamber where the gas used for the dry etching is introduced, a flow or a flow-ratio flow of the introduced gas, and output power or frequency of a high frequency power used for the etching.

Eighth Embodiment

The present embodiment is a modification of a terminal structure (shown inFIG. 14C) mentioned in the sixth embodiment. With reference toFIGS. 6, 7 and 16, an eighth embodiment will be described. In the vertical field type liquid crystal display device described in the third embodiment, as shown inFIGS. 6 and 7, the transparent conductive wiring7formed on the transparent resin layer9is formed to extend in the X-direction. When the transparent conductive wiring7is formed into a film on the transparent resin layer9, a film is also formed in advance on a portion where the surface (second surface15b) of the transparent substrate15is exposed, i.e. on the terminal portion11in the outer region15d, using a conductive oxide such as ITO or the like. In other words, during the process for forming the transparent conductive wiring7, an ITO film is simultaneously formed on the terminal portion11in the outer region15d. In this case, since the ITO is a hard film similar to ceramic, the terminal portion11is unlikely to be scratched so that stable electrical mounting can be made on the terminal portion11.

The display device according to the embodiments of the present invention can be used in various ways. Electronic equipment to which the display device according to the embodiments of the present invention can be applied includes cellular phones, portable game machines, portable information terminals, personal computers, electronic books, video cameras, digital still cameras, head-mount displays, navigation systems, sound-reproducing system (car audio, digital audio player or the like), copying machines, facsimiles, printers, printer composite apparatuses, vending machines, automatic teller machines (ATMs), personal identification devices, optical communication equipment or the like. The above-described embodiments can be combined as desired.

Preferred embodiments of the present invention have so far been described. However, these embodiments are only examples, and should not be construed as limiting the present invention. Additions, omissions, replacements, and other modifications can be made without departing from the scope of the present invention. Accordingly, the present invention should not be construed as being limited by the above description, but should be construed as being defined by the claims.

PTL 1 describes a configuration in which a transparent conductive layer and a light-shielding metal film which are laminated on a plastic film. However, the configuration disclosed in PTL 1 is difficult to be applied to the in-cell structure. Further, since the base material is made of film, the film base material cannot be applied to the high-definition color filter because of the above-mentioned reason. Specifically, the plastic film is likely to be influenced by heat or moisture, so that the dimensions of the plastic film are likely to change significantly. Therefore, it is difficult to align positions between a plurality of patterns including color patterns or black matrix patterns composing pixels of 400 ppi or more, and also difficult to reproduce the pixel pattern. Moreover, PTL 1 fails to teach combining the in-cell technique with the color filer (i.e., integration). For example, according to paragraph [0026] of PTL 1, aluminum is disclosed as a light-shielding metal film. In the manufacturing process of red pixels, green pixels, blue pixels and the black matrix, a photolithography technique is used by using an alkali development solution. However, since the metal pattern made of aluminum is corrosive with an alkali development solution, it is difficult to form the color filter. Furthermore, PTL 1 does not make mention of decline of visibility to the observer who observes the display device, caused by light reflection reflected at the surface of the light-shielding metal film.

PTL 2 describes a configuration where a light absorbing layer having low total reflectance and a conductive layer are laminated, and also disclose a touch panel (e.g., claim 25 of PTL 2). However, PTL 2 does not suggest incorporating the in-cell technique into the color filter (i.e., integration). For example, according to paragraphs [0071] and [0096], and example 2 of PTL 2, aluminum is exemplified as a material of the conductive pattern (or conductive layer). In the manufacturing process of red pixels, green pixels, blue pixels and the black matrix, a photolithography technique is used by using an alkali development solution. However, since the metal pattern is corrosive with an alkali development solution, it is difficult to form the color filter. For example, as recited in claim 14 of PTL 2, use of total reflectance of 3% or less is defined in a configuration provided with a light absorbing layer on an opposite surface with respect to the surface contacting the base material. However, according to examples 1 to 7, the measured wavelength of the total reflectance is 550 nm. According to PTL 2, e.g., FIGS. 11, 16 or FIG. 18, there is no disclosure of a configuration achieving the total reflectance 3% or less in light-wavelength region ranging from 400 nm to 700 nm of the visible light region. For example, since the reflectance shown in FIG. 18 shows a large reflectance in a blue region ranging from 400 nm to 500 nm, the color of light absorbing layer is not observed as black, but is observed as blue, which lowers the visibility.

According to claim 24 or example 3 of PTL 2, copper (Cu) is described as a metal forming the conductive layer. However, there is a concern that sufficient adhesive property of the base material cannot be obtained relative to copper, copper oxide, or copper-oxide nitride, in the case where a glass substrate such as non-alkali glass is used as a base material. For example, there is a practical problem that, in the case where a copper-containing film is formed on the base material using these materials, when Sellotape (registered trademark) or the like is adhered to the copper-containing film, and then the Sellotape is peeled off, the copper-containing film is easily peeled off from the base material. Therefore, PTL 2 does not disclose detailed technique in order to improve adhesive property in the configuration in which the conductive layer containing copper is formed on the base material.

PTL 3 describes a display device provided with touch sensing electrodes, a black region and a color filter layer to display color images, being disposed on an outer surface of the front substrate composing the display panel (e.g., PTL 3, claims 1, 2, or FIG. 3). The touch sensing electrodes are formed of a metallic material and overlap with the black region (black matrix) excluding the pixel opening region. Claim 7 of PTL 3 discloses a configuration where the transparent conductive layer is laminated on the touch sensing electrodes, however, a technique using a layer containing indium is not disclosed. Moreover, PTL 3 does not disclose a configuration in which a black colored layer containing carbon as a color material is laminated on the surface of the touch sensing electrodes. As described in paragraph [0043] of PTL 3, copper is not considered as a metallic material for forming the touch sensing electrodes.

An aspect of the present invention is to provide a black electrode substrate provided with a pixel opening portion having high opening ratio, having improved visibility and high adhesiveness to a transparent substrate, and achieving good electrical connection. Another aspect of the present invention is to provide a method of manufacturing the black electrode substrate and a display device provided with the black electrode substrate.

A black electrode substrate of a first aspect according to the present invention includes a transparent substrate provided with a first surface serving as a touch-sensing input surface, a second surface disposed on an opposite side to the first surface, a display region defined on the second surface, having a rectangular shape in plan view, and an outer region defined on the second surface and located at an outer side of the display region; a first black layer disposed in the display region and the outer region of the second surface, and containing carbon as a major color material; a first indium-containing layer disposed on the first black layer, and containing indium; a copper-containing layer disposed on the first indium-containing layer, and containing copper; a second indium-containing layer disposed on the copper-containing layer, and containing indium; a second black layer disposed on the second indium-containing layer, and containing carbon as a major color material; a black electrode pattern defined by a black wiring, forming a plurality of pixel opening portions in the display region and having a terminal portion, the black wiring having a laminated structure composed of the first black layer, the first indium-containing layer, the copper-containing layer, the second indium-containing layer and the second black layer, the terminal portion being formed such that the second indium-containing layer in the laminated structure of the black wiring disposed in the outer region is exposed therefrom; and a transparent resin layer formed on the display region to overlap the black electrode pattern, and having a rectangular shape of which the size is the same as the display region in plan view.

The copper-containing layer is a metal layer such as a copper layer or a copper alloy layer. An indium-containing layer is provided on a boundary surface between a copper-containing layer and a transparent substrate, or on a boundary surface between a copper-containing layer and an organic resin layer such as a black layer, whereby a practical black wiring can be provided.

In the black electrode substrate of the first aspect according to the present invention, a line width of the first black layer, a line width of the first indium-containing layer, a line width of the copper-containing layer, a line width of the second indium-containing layer, and a line width of the second black layer are preferably the same, in the laminated structure of the black wiring.

In the black electrode substrate of the first aspect according to the present invention, each of the first indium-containing layer and the second indium-containing layer is preferably an alloy layer containing copper and indium.

In the black electrode substrate of the first aspect according to the present invention, each of the first indium-containing layer and the second indium-containing layer is preferably a metal oxide layer containing indium oxide as a major material.

In the black electrode substrate of the first aspect according to the present invention, each of the first indium-containing layer and the second indium-containing layer is preferably a metal oxide layer constituting a mixed oxide containing indium oxide and tin oxide.

In the black electrode substrate of the first aspect according to the present invention, at least a red layer, a green layer and a blue layer are preferably arranged in each of the plurality of pixel opening portions, the transparent resin layer being formed to cover the red layer, the green layer and the blue layer.

A manufacturing method of forming a black electrode substrate of a second aspect according to the present invention includes steps of preparing a transparent substrate provided with a first surface serving as a touch-sensing input surface, a second surface disposed on an opposite side of the first surface, a display region defined on the second surface, having a rectangular shape in plan view, and an outer region defined on the second surface and located at an outer side of the display region; forming a first black overall film containing carbon as a major color material on the transparent substrate; forming a first indium-containing overall film containing indium on the first black overall film; forming a copper-containing overall film containing copper on the first indium-containing overall film; forming a second indium-containing overall film containing indium on the copper-containing overall film; forming a second black overall film containing carbon as a major color material on the second indium-containing overall film; forming a second black layer by patterning the second black overall film; forming, by using the second black layer as a mask, a black electrode pattern defined by a black wiring having a laminated structure composed of the first black layer, the first indium-containing layer, the copper-containing layer, the second indium-containing layer and the second black layer, by etching the first black overall film, the first indium-containing overall film, the copper-containing overall film, and the second indium-containing overall film; forming a transparent resin layer on the display region to expose the outer region, the transparent resin layer having a rectangular shape of which the size is the same as the display region in plan view; and forming, on the outer region, a terminal portion where the second indium-containing layer is exposed, by removing a part of the transparent resin layer in a thickness direction and the second black layer located in the outer region, by dry etching using fluorocarbon-based gas.

A display device of a third aspect according to the present invention is provided with the above-described black electrode substrate of the first aspect.

A display device of a fourth embodiment according to the present invention includes the black electrode substrate according to the first aspect; a transparent conductive wiring laminated on the transparent resin layer of the black electrode substrate and formed to orthogonally cross the black wiring in plan view; an array substrate provided with an active element disposed at a location adjacent to corresponding one of the plurality of pixel opening portions in plan view, and a metal wiring electrically connected to the active element; a liquid crystal layer provided between the transparent conductive wiring and the array substrate; and a control unit having a touch sensing function detecting a change in an electrostatic capacitance produced between the black wiring and the transparent conductive wiring.

A display device of a fifth aspect of the present invention includes the black electrode substrate according to the first aspect; an array substrate provided with an active element disposed at a location adjacent to a corresponding one of the plurality of pixel opening portions in plan view, a metal wiring electrically connected to the active element, and a touch sensing wiring used for touch sensing; a liquid crystal layer provided between the black electrode substrate and the array substrate; and a control unit having a touch sensing function detecting a change in an electrostatic capacitance produced between the black wiring and the touch sensing wiring.

A display device of a sixth aspect of the present invention includes the black electrode substrate according to the first aspect; an array substrate provided with an active element disposed at a location adjacent to a corresponding one of the plurality of pixel opening portions in plan view, a metal wiring electrically connected to the active element and a common electrode forming an electrostatic capacitance with respect to the black wiring; a liquid crystal layer provided between the black electrode substrate and the array substrate; and a control unit having a touch sensing function detecting a change in an electrostatic capacitance produced between the black wiring and the common electrode.

A display device of a seventh aspect of the present invention includes the black electrode substrate according to the first aspect; an array substrate provided with an active element disposed at a location adjacent to a corresponding one of the plurality of pixel opening portions in plan view, a gate line electrically connected to the active element, a touch sensing wiring used for touch sensing, and electrically isolated from the gate line and extending in parallel to the gate line, and a light shielding layer covering the active element and formed of the same metal layer as the touch sensing wiring; a liquid crystal layer provided between the black electrode substrate and the array substrate; and a control unit having a touch sensing function detecting a change in an electrostatic capacitance produced between the black wiring and the touch sensing wiring.

The display device of the aspects according to the present invention can be adapted to liquid crystal display devices, and display devices such as an organic EL display device.

According to the aspect of the present invention, as a touch sensing technique by detecting whether or not a touch of a finger or a pointer or the like exists, for example, a touch sensing technique is known in which a change in an electrostatic capacitance is detected between a black wiring arranged on the black electrode substrate and a transparent conductive wiring arranged facing the black wiring via an insulator such as transparent resin layer. As another touch sensing technique, it has been known that a change in an electrostatic capacitance is detected between a black wiring arranged on the black electrode substrate and a metal wiring included in an array substrate disposed facing the black electrode substrate. In the electrostatic capacitive type touch sensing, the black wiring can be used as a drive electrode or a detection electrode. In the following description, the drive electrode and the detection electrode are referred to as a touch sensing electrode. A minimum configuration in which the black wiring is provided on the transparent substrate is sometimes referred to as a black electrode substrate.

According to the third to seventh aspects of the display device of the present invention, at least a red layer, a green layer and a blue layer are preferably arranged in each of the plurality of pixel opening portions, and the transparent resin layer is preferably formed so as to cover the red layer, the green layer and the blue layer.

According to the third to seventh aspects of the display device of the present invention, the metal wiring preferably has a laminated structure in which a copper-containing layer and two indium-containing layers are laminated, the copper-containing layer containing at least copper and being sandwiched between the two indium-containing layers each containing indium.

According to the third to seventh aspects of the display device of the present invention, the touch sensing wiring preferably has a laminated structure in which a copper-containing layer and two indium-containing layers are laminated, the copper-containing layer containing at least copper and being sandwiched between the two indium-containing layers each containing indium.

According to the third to seventh aspects of the display device of the present invention, the active element is preferably a transistor provided with a channel layer containing two or more metal oxides selected from a group consisting of gallium, indium, zinc, tin and germanium.

According to the aspects of the present invention, without using components having thickness like a touch panel, a black electrode substrate can be provided, including a black wiring having low resistance serving as one electrode of the touch sensing electrode. Further, since a structure using a first indium-containing layer and a second indium-containing layer is employed, a black electrode substrate can be provided, in which an adherence property between the black layer and the copper-containing layer is high, and electrical connection can readily be accomplished between a terminal electrically connected to the copper-containing layer or an electrode and the copper-containing layer. Besides, a black electrode substrate having laminated colored layers can be provided in which a red layer, a green layer, a blue layer or the like are laminated. Moreover, a display device provided with a black electrode substrate having the above-mentioned effects can be provided.

REFERENCE SIGNS LIST

1: first black layer2: first indium-containing layer3: copper-containing layer4: second indium-containing layer5: second black layer6: black wiring60: black wiring7: transparent conductive wiring8: pixel opening portion9: transparent resin layer11,13: terminal portion15,25: transparent substrate15a: first surface15b: second surface15c: display region15d: outer region41,475: source line20,620,720: liquid crystal layer42,471: gate line (scanning line)439,472: touch sensing wiring (touch sensing electrode)473: light shielding layer28,478: gate electrode26: active element24,324,424,474: pixel electrode27: contact hole29: first metal wiring31: conductive portion32: seal portion33,34,25: insulation layer40: second metal wiringR: red layerG: green layerB: blue layerM: end portion of metal wiringMe: terminal portion where second indium-containing layer is exposedS: slit100: black electrode substrate200,300,400,450: array substrate500,600,700,800: display device (liquid crystal display device)
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.