WO2017195339A1

WO2017195339A1 - Display device

Info

Publication number: WO2017195339A1
Application number: PCT/JP2016/064205
Authority: WO
Inventors: 幸弘木村; 福吉　健蔵; 伊藤　大
Original assignee: 凸版印刷株式会社
Priority date: 2016-05-13
Filing date: 2016-05-13
Publication date: 2017-11-16
Also published as: CN109073925B; JP6252689B1; KR102051879B1; CN109073925A; KR20180126594A; JPWO2017195339A1

Abstract

A liquid-crystal display device (LCD1, LCD2, LCD3) according to the present invention includes: a display-device substrate (100); an array substrate (200); a display function layer (300) sandwiched between the display-device substrate (100) and the array substrate (200); and a control unit (120). The display-device substrate (100) includes touch sensing wiring lines (3). The array substrate (200) includes a common electrode (17) having one or more electrode sections (17A) provided individually at a plurality of pixel openings (18); conductive wiring lines (30) electrically connected to the common electrode (17) and crossing the plurality of pixel openings (18) under a second insulating layer (12); active elements (28) implemented by thin-film transistors having a top-gate structure, the active elements (28) being provided under a third insulating layer (13) and electrically connected to pixel electrodes (20); gate wiring lines (10) having the same layer configuration as the conductive wiring lines (30), formed between the second insulating layer and the third insulating layer at the same positions as the conductive wiring lines (30), and extending in a second direction in plan view so as to be electrically linked with the active element; and contact holes (H) provided at the centers in the lengthwise direction of the patterns of the electrode sections (17A) and electrically interconnecting the common electrode (17) and the conductive wiring lines (30). The touch sensing wiring lines (3) and the common electrode (17) face each other in an oblique direction inclined relative to the thickness direction of the display function layer (300).

Description

Display device

The present invention relates to a display device capable of stable touch sensing and having high touch sensing sensitivity.

Display devices having a display function layer are used for large displays such as televisions, tablets, smartphones, and the like. A liquid crystal display device using liquid crystal as a display functional layer has a configuration in which a liquid crystal layer is sandwiched between two transparent substrates such as glass. The main liquid crystal driving method in such a liquid crystal display device is a VA (Vertical Alignment) mode known as a vertical electric field method, an IPS (In-Plane Switching) mode known as a horizontal electric field method, or fringe electric field switching. FFS (Fringe Field Switching) mode can be roughly classified.

Organic EL devices (OLEDs: Organic Light Emitting Diodes) that use organic light-emitting diodes as display functional layers are attracting attention from the viewpoint of reducing the thickness of display devices. EMS (Electro Mechanical System) composed of electrical elements and mechanical elements has attracted attention from the viewpoint of reducing power consumption. A MEMS (Micro-Electro-Mechanical System) includes an optical component such as an actuator, a transducer, a sensor, a micromirror, a MEMS switch, and an optical film, and an interferometric modulator (IMOD). In recent years, a display functional layer in which a plurality of micro LEDs are arranged on a substrate is also known.

In the IPS mode or the FFS mode, liquid crystal driving is performed by horizontally aligning liquid crystal molecules with respect to the substrate surface of the liquid crystal display device and applying an electric field to the liquid crystal molecules in a direction substantially parallel to the substrate surface. The IPS mode or the FFS mode is a liquid crystal driving method used in a liquid crystal display device having a wide viewing angle. A liquid crystal display device adopting the FFS mode has a great merit that a liquid crystal can be driven at high speed by using a fringe electric field.

Regarding the liquid crystal drive system, in order to suppress burn-in of the liquid crystal display, polarity inversion drive (AC inversion drive) is performed to invert the voltage applied to the liquid crystal layer after a predetermined video display period has elapsed. ing. The polarity inversion driving method includes dot inversion driving that individually inverts the polarity of each of a plurality of pixels, and a horizontal line that inverts the polarity of each pixel in a row in which a plurality of pixels are arranged along the horizontal direction of the screen. Inversion driving, column inversion driving to invert the polarity of pixels in a column unit in which a plurality of pixels are arranged along the vertical direction of the screen, inversion of pixel polarity in units of one screen, or screen in a plurality of blocks Frame inversion driving or the like that partitions and inverts the polarity of pixels in units of blocks is known. Such liquid crystal driving techniques are described or suggested in, for example, Patent Documents 1 to 5 and 7.

As such a liquid crystal display device, a liquid crystal display device having a touch sensing function provided with means for detecting capacitance has recently been used. As a touch sensing method, a change in capacitance that occurs when a pointer such as a finger or pen touches or approaches a display screen is detected by, for example, touch sensing wires (touch electrodes) arranged in the X and Y directions. This method is mainly used.
As the structure of a display device having a touch sensing function, an out-cell method in which a touch panel having a touch sensing function is attached to the surface of the display device and an in-cell method in which the display device itself has a touch sensing function are known. ing. In recent years, more display devices have adopted the in-cell method than the out-cell method.

Patent Documents 2 to 6 disclose touch sensing technology using an in-cell method. However, the in-cell method has a problem of touch sensing technology that is not clarified in these patent documents. In other words, a problem that is not likely to be a problem with the external touch panel method, that is, the touch sensing wiring is easily affected by noise from the source wiring electrically linked to the active element provided in the liquid crystal cell. There are major technical issues.

Patent Document 1 discloses a technique for reversing the polarity of pixels in units of columns in which a plurality of pixels are arrayed along the vertical direction of the screen with respect to liquid crystal driving. Patent Document 1 does not include touch sensing technology.
Patent Document 2 includes a description about dot inversion driving and discloses a touch sensing technique. In the disclosure of Patent Document 2, the drive electrode and the detection electrode that perform the touch sensing function are substantially configured by metal wiring.
Patent Document 3 relates to an in-plane switching (IPS) liquid crystal display and discloses a technique in which touch sensing drive electrodes form electrode pairs used for detection of touch sensing signals and display. Such disclosure of Patent Document 3 is similar to the feature point of Claim 2 described in Patent Document 5.

Patent Document 4 discloses a structure in which a touch screen technology is incorporated in a vertical electric field type liquid crystal display device in which counter electrodes are stacked on a color filter. Such a structure is shown, for example, in claim 1 and Example of Patent Document 4. Further, as described in claim 1 of Patent Document 4, the display pixel includes a storage capacitor. Further, the touch drive electrode operates as a counter electrode of the storage capacitor during the display operation. It should be noted that the paragraph 0156 et seq. Of Patent Document 4 discloses a configuration in which two types of in-plane switching (IPS) electrodes are parallel to each other in a single plane. Patent Document 4 paragraph 0157 shows that an IPS display lacks a Vcom layer that can be used for touch drive or touch sensing.
In the structure disclosed in Patent Document 4, it is necessary to cross over yVcom to xVcom (paragraph 0033 of Patent Document 4, FIG. 5, FIG. 1E, FIG. 1F, etc.).

Patent Document 5 discloses a touch sensing technique using strip-shaped conductors orthogonal to each other in a liquid crystal cell.
Patent Document 6 discloses a plurality of touch drive electrodes (connected to the interconnection conductor xVcom as a drive region) made of a transparent material and extending in the first direction, and a plurality of touch detection electrodes (as sense regions) extending in the second direction. and one of the touch drive electrode and the touch detection electrode functions as a counter electrode of the liquid crystal display.
Patent Document 6 discloses a technique for performing touch sensing between a drive line including a first group of a plurality of display pixels and a sense line including a second group of the plurality of display pixels. It has a very complicated configuration in which a bypass tunnel is provided between circuit elements.

Japanese Patent Application Laid-Open No. H10-228561 discloses a means for suppressing deterioration in image quality when liquid crystal driving line sequential scanning is performed. In Patent Document 7, a polysilicon semiconductor is used for an active element (TFT: Thin Film Transistor) that drives liquid crystal. Furthermore, by providing a transfer circuit including a latch unit to hold the potential, a potential drop of a scanning signal line specific to a polysilicon TFT having a large off-leakage current is prevented and a picture quality of a liquid crystal display is prevented from being lowered.
Further, from the description of FIGS. 6, 7, and paragraph 0035 of Patent Document 7, the touch detection electrodes and the pixel signal lines are configured to be parallel and overlap in a plan view. Essentially, the S / N ratio (especially “S”, signal value) can be increased by shortening the distance between the touch detection wiring and the touch drive electrode COML. However, in a configuration in which the touch detection electrode and the pixel signal line are formed in a long line shape and overlapped so as to extend in the longitudinal direction of the pixel in plan view, the touch detection electrode and the pixel signal line are brought closer to each other by bringing them closer to each other. The parasitic capacitance generated between the two lines is increased. In other words, “N” (noise) generated from the pixel signal line is easily added to the touch detection electrode, and as a result, the S / N ratio is hardly improved.

In paragraph 0064 of Patent Document 8, as a wiring structure of a thin film transistor signal line, a scanning line, and a storage capacitor line used for driving a liquid crystal, a three-layer metal wiring composed of an indium-containing layer / copper / indium-containing layer Techniques for forming the are disclosed.
Patent Document 8 discloses a configuration in which signal lines (source lines) and pixel electrodes are included in a touch sensing space described later. Since the signal line (source line) and the pixel electrode are noise generation sources, it is not considered to reduce the influence of noise caused by the signal (video signal) to touch sensing. For example, the fourth embodiment of Patent Document 8 and FIG. 11 disclose a configuration in which a pixel electrode is provided on a common electrode used for touch sensing and formed of a transparent conductive film such as ITO. . A liquid crystal driving voltage for frequently rewriting a signal for video display supplied via the source line is applied to the pixel electrode. Therefore, the configuration shown in FIG. 11 in which the pixel electrode is provided on the common electrode is not preferable. Further, the fifth embodiment of Patent Document 8 and FIG. 12 disclose a configuration in which a source wiring is provided in addition to a pixel electrode on a touch sensing wiring. For this reason, it is easier to pick up more noise and parasitic capacitance than the structure shown in FIG. 11, and in this respect, the most undesirable configuration is disclosed. In the example shown in FIG. 12, the gate line is located at the bottom in the Y direction, and the thin film transistor has a bottom gate structure.

The techniques disclosed in Patent Literature 1 to Patent Literature 8 do not sufficiently consider means for reducing noise caused by source wiring to which video signals for performing video display are applied, and are highly sensitive. It is difficult to provide touch sensing technology. Furthermore, it is insufficient to suppress the generation of noise related to liquid crystal driving.

Japanese Patent Publication No.4-222486 Japanese Unexamined Patent Publication No. 2014-109904 Japanese Patent No. 4584342 Japanese Patent No. 5517611 Japanese Unexamined Patent Publication No. 7-36017 Japanese Patent No. 5,746,736 Japanese Unexamined Patent Publication No. 2014-182203 Japanese Patent No. 5807726

In a display device that employs an in-cell method and has a touch sensing function, countermeasures against noise generated by liquid crystal driving are indispensable for improving sensing sensitivity.
As described above, polarity inversion driving is generally employed as liquid crystal driving in order to avoid display sticking due to charge accumulation. However, the source wiring for transmitting the video signal has been a source for generating noise due to polarity inversion. In addition, the source wiring is likely to be accompanied by a change in parasitic capacitance accompanying the polarity inversion of the video signal. In a display device that employs the in-cell method and has a touch sensing function, it is important to suppress the generation of noise due to the source wiring to which the video signal is transmitted.

Further, as disclosed in Patent Document 6, in the method in which the array substrate (TFT substrate) has a touch sensing function, the array substrate (TFT substrate) is located very close to a signal wiring such as a source wiring or a gate wiring that drives the active element (TFT). In addition, wiring related to touch sensing (hereinafter referred to as touch sensing wiring) is disposed in parallel with these wirings. In particular, a source wiring that transmits video signals with various voltages and at a high frequency has a great adverse effect on the touch sensing wiring.
In an active element using a polysilicon semiconductor as a channel layer of a transistor, a leakage current is large, and it is necessary to rewrite the video signal frequently, and there is a concern that noise generated from the source wiring may affect the touch sensing wiring. Is done. Further, in a structure in which the TFT substrate has a touch sensing function, a sense line (touch signal detection wiring), a drive line (touch sensing drive wiring), and a source wiring and a gate wiring for driving an active element are combined into one sheet. In the case of being attached to the array substrate, it is necessary to provide a jumper line, a bypass tunnel, or the like. That is, a complicated configuration that causes high costs is required.
In addition, in order to reduce the leakage current of the polysilicon semiconductor, it is necessary to adopt a double gate structure in which two TFTs are connected to the pixel electrode in each pixel. The aperture ratio is lowered.

The present invention has been made in view of the above problems, and provides a liquid crystal display device that reduces the influence of noise that affects touch sensing in a liquid crystal display device that is a horizontal electric field method typified by the FFS mode. To do.

A display device according to an aspect of the present invention includes a display device substrate including a first transparent substrate, and touch sensing wiring provided on the first transparent substrate and extending in a first direction, and a second transparent substrate. A plurality of polygonal pixel openings on the second transparent substrate, and one or more electrode portions provided in each of the plurality of pixel openings and extending in the first direction in plan view. A common electrode, a first insulating layer provided under the common electrode, a pixel electrode provided under the first insulating layer in each of the plurality of pixel openings, and under the pixel electrode A second insulating layer provided; and is electrically connected to the common electrode under the second insulating layer and extends in a second direction orthogonal to the first direction and crosses the plurality of pixel openings. Conductive wiring to be connected and a third insulation provided under the conductive wiring. An active element which is a thin film transistor having a top gate structure provided under the third insulating layer and electrically connected to the pixel electrode; and the second layer having the same layer configuration as the conductive wiring A gate wiring formed between the insulating layer and the third insulating layer at the same position as the conductive wiring and extending in the second direction in plan view and electrically linked to the active element; A source wiring that extends in the first direction and is electrically linked to the active element in a plan view, and is provided at the center in the longitudinal direction of the pattern of the electrode portion, and the common electrode and the conductive wiring; An array substrate having a contact hole for electrically connecting the display substrate, a display functional layer sandwiched between the display device substrate and the array substrate, the pixel electrode, and the common electrode A control unit that performs video display by driving the display function layer by applying a driving voltage therebetween, and detecting a change in capacitance between the common electrode and the touch sensing wiring. And including. In the oblique direction inclined with respect to the thickness direction of the display function layer, the touch sensing wiring and the common electrode face each other.

The “display function layer” in one embodiment of the present invention means a layer that realizes a function of performing an action such as light transmission, light shielding, light reflection, or light emission between electrodes. Examples of such a display function layer include a liquid crystal element, an organic EL element, an EMS element, a MEMS element, an IMOD element, and a micro LED element.

In the display device according to one aspect of the present invention, the common electrode may have a stripe pattern extending in a longitudinal direction parallel to the touch sensing wiring in a plan view.

In the display device according to one embodiment of the present invention, the active element may include a channel layer made of an oxide semiconductor, and the channel layer may be a thin film transistor in contact with a gate insulating film.

In the display device according to one embodiment of the present invention, the oxide semiconductor is an oxide semiconductor including two or more metal oxides of gallium, indium, zinc, tin, aluminum, germanium, antimony, bismuth, and cerium. There may be.

In the display device according to one embodiment of the present invention, the gate insulating film may be a gate insulating film formed of a complex oxide containing cerium oxide.

In the display device according to one embodiment of the present invention, the display functional layer is a liquid crystal layer, and the liquid crystal of the liquid crystal layer has an initial alignment parallel to the array substrate, and the common electrode, the pixel electrode, It may be driven by a fringe electric field generated by a liquid crystal driving voltage applied between the two.

In the display device according to one embodiment of the present invention, the common electrode and the pixel electrode may be composed of a composite oxide containing at least indium oxide and tin oxide.

In the display device according to one aspect of the present invention, the touch sensing wiring may be formed of a metal layer including a copper alloy layer.

In the display device according to one embodiment of the present invention, the touch sensing wiring may have a structure in which a copper alloy layer is sandwiched between conductive metal oxide layers.

In the display device according to one embodiment of the present invention, the conductive wiring may have a structure in which a copper alloy layer is sandwiched between conductive metal oxide layers.

In the display device according to one embodiment of the present invention, the conductive metal oxide layer may be a composite oxide layer containing two or more of indium oxide, zinc oxide, antimony oxide, and tin oxide.

In the display device according to an aspect of the present invention, the display device substrate includes a black matrix provided between the first transparent substrate and the touch sensing wiring, and the touch sensing wiring includes the black matrix. You may superimpose on a part of.

In the display device according to one aspect of the present invention, the display device substrate may include a color filter provided at a position corresponding to the plurality of pixel openings.

According to one embodiment of the present invention, it is possible to provide a liquid crystal display device in which noise that adversely affects touch sensing is reduced and the wiring structure related to touch sensing is simplified. In addition, a configuration in which the source wiring or the pixel electrode to which the video signal is supplied is not included in the touch sensing space can be realized, and noise related to the video signal can be reduced.

It is a block diagram which shows the control part (a video signal control part, a system control part, and a touch sensing control part) and a display part which comprise the display apparatus which concerns on 1st Embodiment of this invention. It is a top view which shows partially the array substrate which comprises the display apparatus which concerns on 1st Embodiment of this invention, and is the top view seen from the observer side. FIG. 3 is a cross-sectional view partially showing the display device according to the first embodiment of the present invention, and is a cross-sectional view taken along the line A-A ′ shown in FIG. 2. FIG. 3 is a cross-sectional view partially showing the display device according to the first embodiment of the present invention, and is a cross-sectional view taken along the line B-B ′ shown in FIG. 2. It is sectional drawing which shows partially the display apparatus which concerns on 1st Embodiment of this invention, and is an expanded sectional view which expands and shows a common electrode. FIG. 3 is a cross-sectional view partially showing the display device according to the first embodiment of the present invention, and is a cross-sectional view taken along the line C-C ′ shown in FIG. 2. FIG. 3 is a plan view partially showing the display device according to the first embodiment of the present invention, in which a display device substrate including a color filter and touch sensing wiring is stacked on the array substrate shown in FIG. 2 via a liquid crystal layer. It is a top view which shows the made structure. FIG. 7 is a cross-sectional view partially showing the display device substrate according to the first exemplary embodiment of the present invention, and is a cross-sectional view taken along the line F-F ′ shown in FIG. 6. It is sectional drawing which shows the display apparatus substrate which concerns on 1st Embodiment of this invention partially, and is sectional drawing explaining the terminal part of touch sensing wiring. It is sectional drawing which shows the display apparatus substrate which concerns on 1st Embodiment of this invention partially, and is sectional drawing explaining the terminal part of touch sensing wiring. FIG. 3 is a plan view partially showing the array substrate according to the first embodiment of the present invention, and is a diagram for explaining one step of the manufacturing process of the array substrate, showing a pattern of the channel layer of one component of the active element . In FIG. 10, the broken lines indicate the positions of source wirings and gate wirings formed in the subsequent steps. FIG. 2 is a plan view partially showing the array substrate according to the first embodiment of the present invention, and is a plan view for explaining one step in the manufacturing process of the array substrate. On the channel layer, a source wiring, a source electrode, and It is a top view which shows the structure in which each pattern of the drain electrode was formed. FIG. 2 is a plan view partially showing the array substrate according to the first embodiment of the present invention, and is a plan view for explaining one process among the manufacturing processes of the array substrate, and a gate electrode and a gate wiring through a gate insulating film 2 is a plan view showing a structure in which each pattern of conductive wiring is formed. FIG. In FIG. 12, each of the gate electrode, the gate wiring, and the conductive wiring has a stacked structure formed of a plurality of layers including a metal layer and the like. FIG. 3 is a plan view partially showing the array substrate according to the first embodiment of the present invention, and is a plan view for explaining one process among the manufacturing processes of the array substrate, in which a pattern of pixel electrodes is formed through an insulating layer. FIG. Note that the stacked structure in which the common electrode is formed on the array substrate shown in FIG. 13 via the insulating layer corresponds to the structure shown in FIG. 6 is a timing chart showing an example of time-division driving for performing liquid crystal driving and touch sensing driving in the display device according to the embodiment of the present invention. It is a top view which shows partially the pixel of the display apparatus which concerns on 1st Embodiment of this invention, Comprising: It is a top view which shows the orientation state of the liquid crystal in one pixel. FIG. 2 is a plan view partially showing a pixel of the display device according to the first embodiment of the present invention, and showing a liquid crystal driving operation when a liquid crystal driving voltage is applied between the pixel electrode and the common electrode. is there. In the display device according to the first embodiment of the present invention, when the touch sensing wiring functions as a touch drive electrode and the common electrode functions as a touch detection electrode, an electric field is generated between the touch sensing wiring and the common electrode. It is a schematic cross section which shows the produced | generated state. FIG. 3 is a schematic cross-sectional view showing the display device according to the first embodiment of the present invention, and is a cross-sectional view showing a change in the generation state of an electric field when a pointer such as a finger contacts or approaches the surface on the viewer side of the display device substrate It is. It is sectional drawing which shows partially the principal part of the array substrate which comprises the display apparatus which concerns on the modification of 1st Embodiment of this invention. It is a top view which shows partially the array substrate which comprises the display apparatus which concerns on 2nd Embodiment of this invention, and is the top view seen from the observer side. FIG. 21 is a cross-sectional view partially showing an array substrate constituting a display device according to a second embodiment of the present invention, and is a cross-sectional view taken along the line D-D ′ shown in FIG. 20. It is a top view which shows partially the display apparatus which concerns on 2nd Embodiment of this invention, and has the structure where the display apparatus board | substrate which comprises a color filter and touch sensing wiring was laminated | stacked through the liquid crystal layer on the array substrate. It is the top view shown, and is the top view seen from the observer side. FIG. 21 is a cross-sectional view partially showing an array substrate constituting a display device according to a second embodiment of the present invention, and is a cross-sectional view taken along line E-E ′ shown in FIG. 20. It is a top view which shows partially the pixel of the display apparatus which concerns on 2nd Embodiment of this invention, Comprising: It is a top view which shows the orientation state of the liquid crystal in one pixel. FIG. 6 is a plan view partially showing a pixel of a display device according to a second embodiment of the present invention, and showing a liquid crystal driving operation when a liquid crystal driving voltage is applied between the pixel electrode and the common electrode. is there. FIG. 4 is a cross-sectional view partially showing a display device employing FFS mode liquid crystal, and showing a liquid crystal drive operation by a fringe electric field when a liquid crystal drive voltage is applied between a pixel electrode and a common electrode. . It is a top view which shows partially the array substrate which comprises the display apparatus which concerns on 3rd Embodiment of this invention. It is a top view which shows partially the display apparatus which concerns on 3rd Embodiment of this invention, and has the structure where the display apparatus board | substrate which comprises a color filter and touch sensing wiring was laminated | stacked on the array substrate through the liquid crystal layer. It is the top view shown, and is the top view seen from the observer side. It is sectional drawing which shows partially the array substrate which comprises the display apparatus which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows typically the display part of the conventional liquid crystal display device with an equipotential line. It is sectional drawing which shows typically the modification of the display part of the conventional liquid crystal display device with an equipotential line. It is an enlarged plan view which shows one pixel of the conventional liquid crystal display device using FFS mode.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the following description, the same or substantially the same functions and components are denoted by the same reference numerals, and the description thereof is omitted or simplified, or only when necessary. In each of the drawings, the dimensions and ratios of the respective components are appropriately changed from the actual ones in order to make the respective components large enough to be recognized on the drawings. In addition, elements that are difficult to illustrate, for example, an insulating layer, a buffer layer, a plurality of layers that form a semiconductor channel layer, and a plurality of layers that form a conductive layer, as needed, are included in a liquid crystal display device. Is omitted. As a substrate that can be used for the display device, a glass substrate, a ceramic substrate, a quartz substrate, a sapphire substrate, a semiconductor substrate such as silicon, silicon carbide, or silicon germanium, a plastic substrate, or the like can be used.

In each of the embodiments described below, characteristic parts will be described. For example, description of parts having no difference between components used in a normal liquid crystal display device and the display device according to the present embodiment will be omitted. To do.
In the following description, wirings, electrodes, and signals related to touch sensing may be simply referred to as touch driving wirings, touch detection wirings, touch electrodes, and touch driving signals. A voltage applied to the touch sensing wiring for driving the touch sensing is called a touch driving voltage, and a voltage applied between the common electrode and the pixel electrode for driving the liquid crystal layer which is a display function layer is called a liquid crystal driving voltage. Call it. The conductive wiring may be referred to as common wiring.

The liquid crystal display device LCD1 according to the embodiment of the present invention uses an in-cell method. Here, the “in-cell method” means a liquid crystal display device in which a touch sensing function is built in the liquid crystal display device or a liquid crystal display device in which the touch sensing function is integrated with the liquid crystal display device. Usually, in a liquid crystal display device in which a display device substrate and an array substrate (TFT substrate) are bonded via a liquid crystal layer, a polarizing film is bonded to the outer surface of each of the display device substrate and the array substrate. In other words, the in-cell type liquid crystal display device according to the embodiment of the present invention is located between any two polarizing films facing each other and is touch-sensing at any part constituting the liquid crystal display device in the thickness direction. A liquid crystal display device having a function.

(First embodiment)
(Functional configuration of liquid crystal display device LCD1)
Hereinafter, a liquid crystal display device LCD1 according to a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing a liquid crystal display device LCD1 according to the first embodiment of the present invention. As shown in FIG. 1, the liquid crystal display device LCD1 according to the present embodiment includes a display unit 110, and a control unit 120 for controlling the display unit 110 and a touch sensing function.
The control unit 120 has a known configuration, and includes a video signal control unit 121 (first control unit), a touch sensing control unit 122 (second control unit), and a system control unit 123 (third control unit). I have.

The video signal control unit 121 sets the common electrode 17 (described later) provided on the array substrate 200 to a constant potential, and the gate wiring 10 (described later, scanning line) and the source wiring 31 (described later, provided) provided on the array substrate 200. Signal to the signal line). The video signal controller 121 applies a display liquid crystal driving voltage between the common electrode 17 and the pixel electrode 20 (described later), whereby a fringe electric field is generated on the array substrate 200, and liquid crystal molecules are generated along the fringe electric field. Rotates and the liquid crystal layer 300 is driven. As a result, an image is displayed on the array substrate 200. For example, a rectangular wave video signal is individually applied to each of the plurality of pixel electrodes 20 via a source wiring (signal line). Further, the rectangular wave may be a positive or negative DC rectangular wave or an AC rectangular wave. The video signal control unit 121 sends such a video signal to the source wiring.

The touch sensing control unit 122 applies touch sensing driving voltage to the touch sensing wiring 3 (described later), detects a change in capacitance generated between the touch sensing wiring 3 and the common electrode 17, and performs touch sensing.

The system control unit 123 can control the video signal control unit 121 and the touch sensing control unit 122 to perform liquid crystal driving and capacitance change detection alternately, that is, in a time division manner. Further, the system control unit 123 may have a function of driving the liquid crystal at a frequency different from the liquid crystal drive frequency and the touch sensing drive frequency or at different voltages.
In the system control unit 123 having such a function, for example, a frequency of noise from the external environment picked up by the liquid crystal display device LCD1 is detected, and a touch sensing drive frequency different from the noise frequency is selected. Thereby, the influence of noise can be reduced. Further, in such a system control unit 123, a touch sensing driving frequency can be selected in accordance with the scanning speed of a pointer such as a finger or a pen.

In the liquid crystal display device LCD1 having the configuration shown in FIG. 1, the common electrode 17 has a function of driving a liquid crystal by applying a liquid crystal driving voltage for display between the common electrode 17 and the pixel electrode 20, and the touch sensing wiring 3 And a touch sensing function for detecting a change in capacitance generated between the common electrode 17 and the common electrode 17. Since the touch sensing wiring according to the embodiment of the present invention can be formed of a metal layer having good conductivity, the touch sensitivity can be improved by reducing the resistance value of the touch sensing wiring (described later).

As will be described later, the control unit 120 has a function of performing touch sensing drive by the touch sensing wiring 3 and the common electrode 17 in at least one of the stable period of the video display and the black display stable period after the video display. It is preferable to have.

(Structure of the liquid crystal display device LCD1)
The liquid crystal display device according to the present embodiment can include a display device substrate according to an embodiment described later. The “plan view” described below means a plane viewed from the direction in which the observer observes the display surface of the liquid crystal display device (plane of the display device substrate). The shape of the display part of the liquid crystal display device according to the embodiment of the present invention, the shape of the pixel opening that defines the pixel, and the number of pixels constituting the liquid crystal display device are not limited. However, in the embodiment described in detail below, in plan view, the direction of the short side of the pixel opening is defined as the X direction, the direction of the long side (longitudinal direction) is defined as the Y direction, and the thickness of the transparent substrate The vertical direction is defined as the Z direction, and the liquid crystal display device will be described. In the following embodiments, the liquid crystal display device may be configured by switching between the X direction and the Y direction defined as described above.
In FIGS. 2 to 18, an alignment film that imparts initial alignment to the liquid crystal layer 300, an optical film such as a polarizing film and a retardation film, a protective cover glass, and the like are omitted. A polarizing film is attached to each of the front and back surfaces of the liquid crystal display device LCD1 so that the optical axis is crossed Nicol.

FIG. 2 is a plan view partially showing the array substrate 200 constituting the liquid crystal display device LCD1 according to the first embodiment of the present invention, and is a plan view seen from the observer side. In FIG. 2, in order to easily understand the structure of the array substrate, the display device substrate facing the array substrate is not shown.
The liquid crystal display device LCD1 includes a plurality of source lines 31, a plurality of gate lines 10, and a plurality of common lines 30 (conductive lines) on the array substrate 200. Each of the source wirings 31 is formed to have a linear pattern extending in the Y direction (first direction). Each of the gate wiring 10 and each of the common wiring 30 is formed to have a linear pattern extending in the X direction (second direction). That is, the source line 31 is orthogonal to the gate line 10 and the common line 30. The common wiring 30 extends in the X direction so as to cross the plurality of pixel openings. The plurality of pixel openings are regions defined on the transparent substrate 22.

Furthermore, the liquid crystal display device LCD1 includes a plurality of pixel electrodes 20 arranged in a matrix and a plurality of active elements 28 (thin film transistors) provided so as to correspond to the pixel electrodes 20 and connected to the pixel electrodes 20. With. The pixel electrode 20 is provided in each of the plurality of pixel openings. Specifically, an active element 28 is connected to each of the plurality of pixel electrodes 20. In the example shown in FIG. 2, the active element 28 is provided at the position of the upper right end of the pixel electrode 20.
The active element 28 is connected to the channel layer 27 via a source electrode 24 (described later) connected to the source wiring 31, a channel layer 27 (described later), a drain electrode 26 (described later), and an insulating film 13 (described later). And a gate electrode 25 arranged to face each other. The gate electrode 25 of the active element 28 constitutes a part of the gate wiring 10 and is connected to the gate wiring 10.

In the present embodiment, the liquid crystal display device LCD1 includes a plurality of pixels, and one pixel electrode 20 forms one pixel. By switching driving by the active element 28, a voltage (positive voltage) is applied to each of the plurality of pixel electrodes 20, and the liquid crystal is driven. In the following description, a region where liquid crystal driving is performed by the pixel electrode 20 may be referred to as a pixel, a pixel opening, or a pixel region. This pixel is an area partitioned by the source wiring 31 and the gate wiring 10 in plan view.

Furthermore, the liquid crystal display device LCD1 includes a common electrode 17 at a position facing the pixel electrode 20 in the Z direction. In particular, a common electrode 17 having two stripe patterns is provided for one pixel electrode 20. The common electrode 17 is provided in each of the plurality of pixel openings. The common electrode 17 extends in the Y direction and is parallel to the longitudinal direction of the pixel electrode 20. The length EL of the common electrode 17 in the Y direction is larger than the length of the pixel electrode 20 in the Y direction. The common electrode 17 is electrically connected to the common wiring 30 through a through hole 20S and a contact hole H described later. As shown in FIG. 2, the contact hole H is located at the center in the longitudinal direction of the conductive pattern (electrode portion 17 A, stripe pattern) of the common electrode 17.
The number of common electrodes 17 and the number of contact holes in one pixel can be adjusted by, for example, the pixel width (pixel size).
In the X direction, the width W17A of the common electrode 17 is, for example, about 3 μm. The pitch P17A (distance) between the adjacent common electrodes 17 is, for example, about 4 μm. Specifically, not only on one pixel but also between adjacent pixels, the common electrodes 17 are spaced apart from each other at a pitch P17A in the X direction.
In the example shown in FIG. 2, the common electrode 17 having two stripe patterns is provided for one pixel electrode 20, but the present invention is not limited to this configuration. Depending on the size of the pixel electrode 20, the number of the common electrodes 17 may be one or more, or three or more. In this case, the width W17A and the pitch P17A of the common electrode 17 can be appropriately changed according to the pixel size and the design.

FIG. 3 is a sectional view partially showing the liquid crystal display device LCD1 according to the first embodiment of the present invention, and is a sectional view taken along the line AA ′ shown in FIG. In particular, FIG. 3 is a cross-sectional view along the short side direction of the pixel opening.
FIG. 4A is a sectional view partially showing the liquid crystal display device LCD1 according to the first embodiment of the present invention, and is a sectional view taken along the line BB ′ shown in FIG. FIG. 4B is a sectional view partially showing the liquid crystal display device LCD1 according to the first embodiment of the present invention, and is an enlarged sectional view in which a common electrode is enlarged.
FIG. 5 is a sectional view partially showing the liquid crystal display device LCD1 according to the first embodiment of the present invention, and is a sectional view taken along the line CC ′ shown in FIG.

3 and 4A show the distance W1 between the touch sensing wiring 3 and the common electrode 17. In other words, the distance W1 is a distance in the Z direction in a space including the transparent resin layer 16, the color filter 51 (RGB), the alignment film (not shown), and the liquid crystal layer 300. This space does not include active elements, source lines, and pixel electrodes. In the present embodiment, this space indicated by the distance W1 is referred to as a touch sensing space. Noise generated from noise sources such as active elements and source wirings is generally emitted in a three-dimensional radial pattern. For this reason, the magnitude of noise is 1/3 of the distance W1 (the larger the distance, the smaller the influence of noise).
3 and 4A show the distance W2 between the touch sensing wiring 3 and the source wiring 31. FIG. As indicated by the distance W2, the touch sensing wiring 3 and the source wiring 31 are greatly separated. In addition, as shown in FIGS. 2 and 3, since the common electrode 17 and the source wiring 31 do not overlap in plan view, the parasitic capacitance caused by the source wiring 31 is extremely small. Furthermore, the common electrode 17 provided at a position closest to the touch sensing space has a shape of a small piece for each pixel in the longitudinal direction of the pixel. For this reason, compared with the case where the common electrode extended in a linear shape so as to straddle a plurality of pixels is provided, the common electrode 17 according to the present embodiment can reduce the parasitic capacitance.
According to the structure shown in FIG. 3 and FIG. 4A, it is possible to suppress the influence of noise caused by the video signal supplied to the source wiring 31 on the touch sensing wiring 3. Parasitic capacitance generated between them can be reduced.

The liquid crystal display device LCD1 includes a display device substrate 100 (counter substrate), an array substrate 200 bonded so as to face the display device substrate 100, and a liquid crystal layer 300 sandwiched between the display device substrate 100 and the array substrate 200. .
The backlight unit BU that supplies light L to the liquid crystal display device LCD1 is provided on the back surface of the array substrate 200 constituting the liquid crystal display device LCD1 (the surface opposite to the transparent substrate surface of the array substrate 200 on which the liquid crystal layer 300 is disposed). ). The backlight unit may be provided on the side surface of the liquid crystal display device LCD1. In this case, for example, a reflection plate, a light guide plate, a light diffusion plate, or the like that reflects the light emitted from the backlight unit BU toward the inside of the liquid crystal display device LCD1 is provided on the back surface of the transparent substrate 22 of the array substrate 200. It is done.

(Display device substrate 100)
The display device substrate 100 includes a transparent substrate 21 (first transparent substrate), a touch sensing wiring 3 provided on the transparent substrate 21, a color filter 51 (RGB) formed so as to cover the touch sensing wiring 3, and And a transparent resin layer 16 formed so as to cover the color filter 51.
The touch sensing wiring 3 functions as a touch driving electrode (touch driving wiring). In the liquid crystal display device LCD1, touch sensing is detected by detecting a change in capacitance between the touch sensing wiring 3 and the common electrode 17.
The touch sensing wiring 3 has a laminated structure formed of a conductive layer including at least a black layer 8 and a metal layer 5 formed above the black layer 8. Furthermore, the conductive layer has a three-layer configuration of a first conductive metal oxide layer 6, a metal layer 5, and a second conductive metal oxide layer 4. Further, a black layer or a light absorption layer may be further laminated on the surface (liquid crystal layer side) of the first conductive metal oxide layer 6. There may be a portion having the same line width between the touch sensing wiring 3 and the black layer 8 in plan view.
In the configuration in which the metal layer 5 is sandwiched between the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4, either a conductive metal oxide or a two-layer stack of conductive metal oxides A layer configuration without the above may be employed.

(Metal layer 5)
As the metal layer 5, for example, a copper-containing layer that is a copper layer or a copper alloy layer, or an aluminum alloy layer (aluminum-containing layer) containing aluminum can be employed. Specifically, copper, silver, gold, titanium, molybdenum, aluminum, or an alloy thereof can be applied as the material of the metal layer 5. Since nickel is a ferromagnetic material, it can be formed by vacuum film formation such as sputtering although the film formation rate is lowered. Chromium has the disadvantage of environmental pollution and a large resistance value, but can be used as a material for the metal layer according to the present embodiment. As the metal forming the metal layer 5, in order to obtain adhesion to the transparent substrate 21 and the transparent resin layer 16, copper, aluminum, magnesium, calcium, titanium, molybdenum, indium, tin, zinc, neodymium, nickel, aluminum It is preferable to employ an alloy to which one or more metal elements selected from antimony and silver are added. The amount of the metal element added to the metal layer 5 is preferably 4 at% or less because the resistance value of the copper alloy or aluminum is not greatly lowered. As a copper alloy film forming method, for example, a vacuum film forming method such as sputtering can be used.
When adopting a copper alloy thin film or an aluminum alloy thin film, if the film thickness is 100 nm or more, or 150 nm or more, visible light is hardly transmitted. Therefore, if the metal layer 5 according to the present embodiment has a film thickness of, for example, 100 nm to 300 nm, sufficient light shielding properties can be obtained. The film thickness of the metal layer 5 may exceed 300 nm. As will be described later, the material of the metal layer 5 can also be applied to the common wiring 30 (conductive wiring). A laminated structure in which the metal layer 5 is sandwiched between conductive metal oxide layers can also be applied to the common wiring 30 (conductive wiring).

(Conductive metal oxide layers 4 and 6)
The first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 sandwich the metal layer 5. At the interface between the first conductive metal oxide layer 6 and the metal layer 5 and the interface between the second conductive metal oxide layer 4 and the metal layer 5, copper such as nickel, zinc, indium, titanium, molybdenum, tungsten, etc. Different metals or alloy layers of these metals may be inserted.
Specifically, as the material of the second conductive metal oxide layer 4 and the first conductive metal oxide layer 6, for example, two or more kinds of metals selected from indium oxide, zinc oxide, antimony oxide, and tin oxide are used. A composite oxide containing an oxide can be employed.
The amount of indium (In) contained in the second conductive metal oxide layer 4 and the first conductive metal oxide layer 6 needs to be greater than 80 at%. The amount of indium (In) is preferably greater than 80 at%. More preferably, the amount of indium (In) is greater than 90 at%. When the amount of indium (In) is less than 80 at%, the specific resistance of the conductive metal oxide layer to be formed increases, which is not preferable. If the amount of zinc (Zn) exceeds 20 at%, the alkali resistance of the conductive metal oxide (mixed oxide) decreases, which is not preferable. In the second conductive metal oxide layer 4 and the first conductive metal oxide layer 6 described above, both atomic percentages of metal elements in the mixed oxide (counting only metal elements not counting oxygen elements) It is. Antimony oxide can be added to the conductive metal oxide layer because metal antimony hardly forms a solid solution region with copper and suppresses diffusion of copper in a laminated structure.

The amount of zinc (Zn) contained in the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 needs to be larger than the amount of tin (Sn). If the tin content exceeds the zinc content, there will be problems with wet etching in the subsequent process. In other words, the metal layer made of copper or copper alloy is more easily etched than the conductive metal oxide layer, and the first conductive metal oxide layer 6, the metal layer 5, and the second conductive metal oxide layer 4. A difference in the width is likely to occur.
The amount of tin (Sn) contained in the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 is preferably in the range of 0.5 at% or more and 6 at% or less. In comparison with indium element, by adding tin of 0.5 at% or more and 6 at% or less to the conductive metal oxide layer, a ternary mixed oxide film of indium, zinc, and tin (conductive composite) The specific resistance of the oxide layer can be reduced. If the amount of tin exceeds 6 at%, zinc is also added to the conductive metal oxide layer, so that the specific resistance of the ternary mixed oxide film (conductive composite oxide layer) becomes too large. By adjusting the amount of zinc and tin within the above range (0.5 at% or more and 6 at% or less), the specific resistance is approximately 5 × 10 ⁻⁴ Ωcm or more as the specific resistance of the single layer film of the mixed oxide film. It can be within a small range of 3 × 10 ⁻⁴ Ωcm or less. A small amount of other elements such as titanium, zirconium, magnesium, aluminum, and germanium can be added to the mixed oxide. However, in this embodiment, the specific resistance of the mixed oxide is not limited to the above range.

When the metal layer 5 is a copper layer or a copper alloy layer, the conductive metal oxide layer described above is a composite containing two or more metal oxides selected from indium oxide, zinc oxide, antimony oxide, and tin oxide. An oxide is desirable. The copper layer or the copper alloy layer has low adhesion to the transparent resin layer 16 and the glass substrate (transparent substrate 21) constituting the color filter 51. For this reason, when a copper layer or a copper alloy layer is applied to a display device substrate as it is, it is difficult to realize a practical display device substrate. However, the above-described composite oxide has sufficient adhesion to the color filter 51, the black matrix BM (black layer 8), the glass substrate (transparent substrate 21), and the like, and a copper layer or a copper alloy layer. Adhesion to is also sufficient. For this reason, when a copper layer or a copper alloy layer using a composite oxide is applied to a display device substrate, a practical display device substrate can be realized.

Copper, copper alloy, silver, silver alloy, or oxides and nitrides thereof generally do not have sufficient adhesion to the transparent substrate 21 such as glass, the black matrix BM, and the like. Therefore, when the conductive metal oxide layer is not provided, peeling may occur at the interface between the touch sensing wiring 3 and the transparent substrate 21 such as glass or the interface between the touch sensing wiring 3 and the black layer 8. When copper or a copper alloy is used as the touch sensing wiring 3 having a thin wiring pattern, the display device substrate in which the conductive metal oxide layer is not formed as the base layer of the metal layer 5 (copper or copper alloy) is peeled off. In addition to defects, defects due to electrostatic breakdown may occur in the touch sensing wiring 3 during the manufacturing process of the display device substrate, which is not practical. Such electrostatic breakdown in the touch sensing wiring 3 is caused by static electricity in the wiring pattern by a post process such as laminating the color filter 51 on the transparent substrate 21, a process of bonding the display device substrate and the array substrate, a cleaning process or the like. Is a phenomenon that causes pattern breakage, disconnection, and the like due to electrostatic breakdown.
In addition, non-conductive copper oxide may be formed over time on the surface of the copper layer or copper alloy layer, making electrical contact difficult. On the other hand, a complex oxide layer such as indium oxide, zinc oxide, antimony oxide, and tin oxide can realize a stable ohmic contact. When such a complex oxide layer is used, an electric current such as a transfer described later is used. Can be easily implemented. Further, in the seal portion where the display device substrate and the array substrate are bonded to each other, it is also possible to perform conduction transfer (transfer) from the display device substrate 100 to the array substrate 200 in the thickness direction of the seal portion. By disposing a conductor selected from an anisotropic conductive film, a minute metal sphere, or a resin sphere covered with a metal film in the seal portion, the display device substrate 100 and the array substrate 200 can be electrically connected.

Examples of the metal oxide layer structure of the conductive

metal oxide layers

4 and 6 and the metal layer 5 applicable to the embodiment of the present invention include the following structures. For example, in a state where oxygen is insufficient in ITO (Indium Tin Oxide) or IZTO (Indium Zinc Tin Oxide, Z is zinc oxide) containing indium oxide as a central base material, for example, a metal layer is formed on a copper alloy layer. Layer structure obtained by film formation, or layer obtained by laminating a metal layer on aluminum alloy or copper alloy with molybdenum oxide, tungsten oxide, mixed oxide of nickel oxide and copper oxide, titanium oxide, etc. Examples include the configuration. The layer structure obtained by the conductive metal oxide layer and the metal layer has an advantage that the film can be continuously formed by a vacuum film forming apparatus such as a sputtering apparatus.

(Black layer 8)
The black layer 8 functions as a black matrix BM of the liquid crystal display device LCD1. The black layer is made of, for example, a colored resin in which a black color material is dispersed. Copper oxides and copper alloy oxides cannot obtain sufficient black or low reflectance, but the visible light reflectance at the interface between the black layer and the substrate such as glass according to this embodiment is almost the same. It is suppressed to 3% or less, and high visibility is obtained.

As the black color material, carbon, carbon nanotubes, or a mixture of a plurality of organic pigments can be used. For example, carbon is used at a ratio of 51 mass% or more with respect to the total amount of the color material, that is, as the main color material. In order to adjust the reflection color, an organic pigment such as blue or red can be added to the black color material. For example, the reproducibility of the black layer can be improved by adjusting the concentration of carbon contained in the photosensitive black coating liquid as a starting material (lowering the carbon concentration).

Even when a large exposure apparatus, which is a liquid crystal display manufacturing apparatus, is used, for example, a black layer having a pattern having a width (thin line) of 1 to 6 μm can be formed (patterning). In addition, the range of the carbon concentration in this embodiment is set in the range of 4 to 50% by mass with respect to the total solid content including the resin, the curing agent, and the pigment. Here, as the amount of carbon, the carbon concentration may exceed 50% by mass. However, when the carbon concentration exceeds 50% by mass with respect to the entire solid content, the suitability of the coating film tends to decrease. In addition, when the carbon concentration is set to less than 4% by mass, sufficient black color cannot be obtained, and reflected light generated in the underlying metal layer located under the black layer is greatly recognized, thereby reducing visibility. there were.

When exposure processing is performed in photolithography, which is a subsequent process, alignment between the substrate to be exposed and the mask is performed. At this time, priority is given to alignment, and for example, the optical density of the black layer by transmission measurement can be made 2 or less. In addition to carbon, a black layer may be formed using a mixture of a plurality of organic pigments as a black color adjustment. Considering the refractive index (about 1.5) of the base material such as glass or transparent resin, the reflectance of the black layer is such that the reflectance at the interface between the black layer and the base material is 3% or less. Is set. In this case, it is desirable to adjust the content and type of the black color material, the resin used for the color material, and the film thickness. By optimizing these conditions, the reflectance at the interface between the black layer having a refractive index of approximately 1.5 and the black layer is set to 3% or less in the visible wavelength range. And low reflectivity can be realized. The reflectance of the black layer shall be 3% or less in consideration of the necessity of preventing the reflected light caused by the light emitted from the backlight unit BU from being reflected again and the improvement of the visibility of the observer. Is desirable. In general, the refractive index of the acrylic resin used for the color filter and the liquid crystal material is approximately in the range of 1.5 to 1.7.
Further, by forming a light-absorbing metal oxide on the touch sensing wiring 3 or the conductive wiring (common wiring 30), light reflection by the metal layer 5 used for the touch sensing wiring 3 can be suppressed. .

In the display device substrate 100 shown in FIG. 3, a structure in which the color filter 51 is provided is used, but a structure in which the color filter 51 is omitted, for example, the touch sensing wiring 3 provided on the transparent substrate 21 and Alternatively, a structure including a transparent resin layer 16 formed so as to cover the touch sensing wiring 3 may be used.
In a liquid crystal display device using a display device substrate that does not include the color filter 51, each LED of red light emission, green light emission, and blue light emission is provided in a backlight unit, and color display is performed by a field sequential method. The layer configuration of the touch sensing wiring 3 provided on the transparent substrate 21 shown in FIG. 3 includes the layer configuration of the common wiring 30 (conductive wiring) formed on the array substrate 200 described later and the gate electrode 25 (gate wiring 10). It can be the same as the layer structure.

(Array substrate 200)
As shown in FIGS. 3, 4A, and 4B, the array substrate 200 includes a transparent substrate 22 (second transparent substrate), a fourth insulating layer 14 formed to cover the surface of the transparent substrate 22, A source wiring 31 formed on the fourth insulating layer 14, a third insulating layer 13 formed on the fourth insulating layer 14 so as to cover the source wiring 31, and a gate wiring formed on the third insulating layer 13 10, a common wiring 30 formed on the third insulating layer 13, a second insulating layer 12 formed on the third insulating layer 13 so as to cover the gate wiring 10 and the common wiring 30, and a second insulating layer The pixel electrode 20 formed on the first insulating layer 12, the first insulating layer 11 formed on the second insulating layer 12 so as to cover the pixel electrode 20, and the common electrode 17 are provided.

Materials for forming the first insulating layer 11, the second insulating layer 12, the third insulating layer 13, and the fourth insulating layer 14 include silicon oxide, silicon oxynitride, aluminum oxide, aluminum oxynitride, cerium oxide, and hafnium oxide. Alternatively, a mixed material containing such a material is employed. Alternatively, a polyimide resin, an acrylic resin, a benzocyclobutene resin, or a low dielectric constant material (low-k material) may be used for a part of these insulating layers. Moreover, as a structure of such insulating

layers

11, 12, 13, and 14, a layer structure composed of a single layer may be employed, or a multilayer structure in which a plurality of layers are stacked may be employed. Such insulating

layers

11, 12, 13, and 14 can be formed by using a film forming apparatus such as plasma CVD or sputtering.
The source wiring 31 is disposed between the third insulating layer 13 and the fourth insulating layer 14. As the structure of the source wiring 31, a multi-layered conductive layer can be adopted. In the first embodiment, the source wiring 31 has a three-layer structure of titanium / aluminum alloy / titanium. Here, the aluminum alloy is an aluminum-neodymium alloy.
As a material for forming the common wiring 30, the same material as that of the metal layer 5 described above is employed. Similarly, the structure of the common wiring 30 is the same as that of the metal layer 5 described above.

The pixel electrode 20 is provided in each of the plurality of pixel openings 18, and is connected to an active element (described later) that is a TFT. Since the active elements are arranged in a matrix on the array substrate 200, the pixel electrodes 20 are similarly arranged on the array substrate 200 in a matrix. The pixel electrode 20 is formed of a transparent conductive film such as ITO.

The channel layer or semiconductor layer constituting the active element may be formed of a polysilicon semiconductor or an oxide semiconductor. The layer configuration of the channel layer or the semiconductor layer constituting the active element may be a stacked configuration in which a polysilicon semiconductor and an oxide semiconductor are stacked. An element formed of two types of semiconductors, for example, an active element including a channel layer that is a polysilicon semiconductor and an active element including a channel layer that is an oxide semiconductor are formed on the same surface of the array substrate. There may be. Furthermore, a configuration may be employed in which a TFT array formed of an oxide semiconductor is laminated in two layers on a polysilicon semiconductor TFT array via an insulating layer. When the display function layer is an organic EL (Organic Electroluminescence) layer, the TFT formed of an oxide semiconductor has a function of supplying a signal (selecting a TFT element) to the TFT formed of a polysilicon semiconductor, A TFT formed of a polysilicon semiconductor has a function of driving the display function layer. With this configuration, it is possible to realize a display device in which an organic EL layer is employed as a display function layer. A TFT including a polysilicon semiconductor having a high carrier mobility and having a polysilicon semiconductor as a channel layer is suitable for current injection into an organic EL element (driving the organic EL element).

(Structure of common electrode 17)
With reference to FIG. 4B, the structure of the common electrode 17 and the constituent members of the array substrate 200 located around the common electrode 17 will be described. In particular, a stacked structure including the common wiring 30, the common electrode 17, the pixel electrode 20, the first insulating layer 11, and the second insulating layer 12 will be specifically described. FIG. 4B shows the main part of the pixels constituting the array substrate 200, and shows the structure of one common electrode 17 in one pixel. The structure of the common electrode 17 shown in FIG. 4B is also applied to all the pixels on the array substrate 200.

The second insulating layer 12 is provided below the first insulating layer 11, is formed on the common wiring 30, and has a through hole 12H that forms a part of a contact hole H described later. The first insulating layer 11 is provided below the common electrode 17 (electrode part 17A), is formed on the pixel electrode 20, and has a through hole 11H that forms a part of a contact hole H described later. Have. The position (center position) of the through hole 12H matches the position (center position) of the through hole 11H. The diameter (width in the X direction) of the through hole 11H is gradually reduced in the direction (Z direction) from the upper surface 11T of the first insulating layer 11 toward the common wiring 30. Similarly, the diameter (width in the X direction) of the through hole 12H is gradually reduced in the direction (Z direction) from the upper surface 12T of the second insulating layer 12 toward the common wiring 30. The through hole 11H and the through hole 12H have a continuous inner wall and form a contact hole H. The contact hole H has a tapered shape.

The pixel electrode 20 is formed under the first insulating layer 11 and has a through hole 20S. The through hole 20S is an opening where no transparent conductive film exists. The through hole 20S is provided at a position corresponding to the contact hole H.
In the example shown in FIG. 2, each pixel is provided with two contact holes H, that is, a left contact hole LH (H, first contact hole) and a right contact hole RH (H, second contact hole). Through holes 20S are provided at positions corresponding to the respective contact holes H.
In the following description, the left contact hole LH and the right contact hole RH may be simply referred to as contact holes H.

The through hole 20S corresponds to an inner region of the inner wall 20K provided in the pixel electrode 20. The diameter D20S of the through hole 20S is larger than the diameter of the contact hole H. The through hole 11H (a part of the contact hole H) is provided inside the through hole 20S. The through hole 20S is filled with the first insulating layer 11, and the through hole 11H is formed so as to penetrate the filling portion 11F of the first insulating layer 11 filling the inner wall of the through hole 20S. Furthermore, a through hole 12H (a part of the contact hole H) is formed so as to be continuous with the through hole 11H also at a position below the through hole 20S. Note that the number of through holes 20S formed in the pixel electrode 20 is the same as the number of contact holes H, and is formed at the same position in plan view. The diameter D20S of the through hole 20S is 3 μm to 6 μm, for example. The diameter of the through hole 20 S may be larger than the width W 17 A of the common electrode 17.

The common electrode 17 includes an electrode portion 17A (conductive portion) and a conductive connection portion 17B.
The electrode portion 17A is formed on the upper surface 11T of the first insulating layer 11, and is disposed so as to overlap with the through hole 20S of the pixel electrode 20 when viewed from the Z direction. The electrode portion 17 A is provided on the surface of the array substrate 200 closest to the liquid crystal layer 300. Specifically, an alignment film is formed between the liquid crystal layer 300 and the array substrate 200, and the first insulating layer 11 is provided under the alignment film.
The width W17A of the electrode portion 17A is, for example, about 3 μm, is larger than the upper end of the conductive connection portion 17B (connection portion between the electrode portion 17A and the conductive connection portion 17B), and has a diameter D20S (for example, 2 μm) of the through hole 20S. You may form larger. Alternatively, the diameter D20S of the through hole 20S may be larger than the width W17A of the electrode portion 17A. The diameter D20S of the through hole 20S can be set to 4 μm, for example. In the direction (X direction) from the center of the electrode portion 17A (the center line of the electrode portion 17A parallel to the Z direction) to the outside of the electrode portion 17A, the wall portion 17K of the electrode portion 17A is the same as the inner wall 20K of the pixel electrode 20. It protrudes from the position.
The conductive connection portion 17B is provided inside the contact hole H (through

holes

11H and 12H), and is electrically connected to the common wiring 30 through the contact hole H.
In a state where the contact holes described above are formed in the first insulating layer 11 and the second insulating layer 12, a film forming process and a patterning process are performed on the first insulating layer 11, so that the electrode portion 17A and the conductive connection portion 17B are formed. Are integrally formed. Similar to the pixel electrode 20, the common electrode 17 is formed of a transparent conductive film such as ITO.

In the stacked structure described above, the first insulating layer 11 is disposed between the electrode portion 17 A and the pixel electrode 20, and the second insulating layer 12 is disposed between the common wiring 30 and the pixel electrode 20. Thus, the common electrode 17 and the common wiring 30 are electrically connected to each other, and the potential of the common wiring 30 and the potential of the common electrode 17 are the same.

The potential of the common wiring 30 (or the common electrode 17) can be changed when liquid crystal driving and touch sensing driving (detection of change in capacitance) are performed alternately, that is, in a time division manner. Further, the frequency of the signal applied to the common wiring 30 (or the common electrode 17) is changed when liquid crystal driving and touch sensing driving (detection of change in capacitance) are performed alternately, that is, in time division. be able to. Further, during liquid crystal driving and frame inversion driving, the polarity of the potential of the common wiring 30 (or common electrode 17) is switched between positive polarity and negative polarity for each frame, for example, ± 2.5 V liquid crystal driving. The liquid crystal can be driven by voltage.

When the liquid crystal driving is column inversion driving or dot inversion driving, the potential of the common electrode 17 may be constant (constant potential). The “constant potential” in this case is, for example, the potential of the common electrode 17 that is grounded through a high resistance to the housing of the liquid crystal display device, and is ± 2.5 V or the like used for the frame inversion driving. Does not mean constant potential. This is a constant potential fixed at approximately 0 V (zero volt) within a voltage range equal to or lower than the threshold voltage Vth of the liquid crystal. In other words, the “constant potential” may be a constant potential offset from the intermediate value of the liquid crystal driving voltage as long as it is within the range of Vth. The “high resistance” is a resistance value that can be selected from the range of 500 megaohms to 50 teraohms. As such a resistance value, typically, 500 gigaohm to 5 teraohm can be adopted. When column inversion driving or dot inversion driving is adopted as the liquid crystal driving method, the common wiring 30 is grounded through a high resistance of 1 teraohm, for example, and can be set to a constant potential of about 0 V (zero volt). In this case, the common electrode 17 connected to the common wiring 30 also has a constant potential of about 0 V (zero volts), and the accumulated capacitance can be reset. When the potential of the common electrode 17 is a constant potential, the touch drive voltage is applied to the touch sensing wiring during touch sensing. When the potential of the common electrode 17 is set to “constant potential”, liquid crystal driving and touch driving need not be time-division driven.

Note that in the case where an oxide semiconductor such as IGZO is used as a material for forming a channel layer of an active element (a thin film transistor) of a liquid crystal display device, the above-mentioned high A resistance lower than 1 teraohm may be used as the resistance.
During black display, which will be described later, the gate wiring and the source wiring may be grounded through the high resistance. In this case, pixel burn-in can be prevented.
Further, the high resistance can be adjusted for the purpose of adjusting the time constant related to touch sensing. In a display device using an oxide semiconductor such as IGZO for the channel layer of the active element, the above-described various devices in touch sensing control can be achieved. In the following description, an oxide semiconductor may be simply referred to as IGZO.

(Active element 28)
Next, the structure of the active element 28 connected to the pixel electrode 20 will be described with reference to FIG.
FIG. 5 shows an example of a thin film transistor (TFT) having a top gate structure.
The active element 28 includes a channel layer 27, a drain electrode 26 connected to one end of the channel layer 27 (first end, the left end of the channel layer 27 in FIG. 5), and the other end (second end, FIG. 5 is connected to the right end of the channel layer 27), and the gate electrode 25 is disposed opposite to the channel layer 27 with the third insulating layer 13 interposed therebetween. FIG. 5 shows a structure in which the channel layer 27, the drain electrode 26, and the source electrode 24 constituting the active element 28 are formed on the fourth insulating layer 14, but the present invention is limited to such a structure. Not. The active element 28 may be directly formed on the transparent substrate 22 without being provided on the fourth insulating layer 14.
Video signals are supplied to the source wiring 31 at a high frequency, and noise is easily generated from the source wiring 31. The top gate structure has an advantage that the source wiring 31 that is also a noise generation source can be moved away from the touch sensing space described above.
The source electrode 24 and the drain electrode 26 shown in FIG. 5 are formed of conductive layers having the same structure in the same process. In the first embodiment, a three-layer structure of titanium / aluminum alloy / titanium is adopted as the structure of the source electrode 24 and the drain electrode 26. Here, the aluminum alloy is an aluminum-neodymium alloy.
The insulating layer 13 located below the gate electrode 25 may be an insulating layer having the same width as the gate electrode 25. In this case, for example, dry etching using the gate electrode 25 as a mask is performed, and the insulating layer 13 around the gate electrode 25 is removed. As a result, an insulating layer having the same width as the gate electrode 25 can be formed. A technique for processing an insulating layer by dry etching using the gate electrode 25 as a mask is generally called self-alignment.

As the material of the channel layer 27, for example, an oxide semiconductor called IGZO can be used. As a material of the channel layer 27, an oxide semiconductor containing two or more metal oxides of gallium, indium, zinc, tin, aluminum, germanium, antimony, bismuth, and cerium can be used. In this embodiment, an oxide semiconductor containing indium oxide, gallium oxide, and zinc oxide is used. The material of the channel layer 27 formed of an oxide semiconductor may be any of single crystal, polycrystal, microcrystal, a mixture of microcrystal and amorphous, or amorphous. The thickness of the oxide semiconductor can be in the range of 2 nm to 50 nm. The channel layer 27 may be formed of a polysilicon semiconductor.

An oxide semiconductor or a polysilicon semiconductor can be used, for example, in the configuration of a complementary transistor having a p / n junction, or can be used in the configuration of a single channel transistor having only an n-type junction. As the stacked structure of the oxide semiconductor, for example, a stacked structure in which an n-type oxide semiconductor and an n-type oxide semiconductor having different electrical characteristics from the n-type oxide semiconductor are stacked may be employed. The n-type oxide semiconductor to be stacked may include a plurality of layers. In the stacked n-type oxide semiconductor, the band gap of the underlying n-type semiconductor can be different from the band gap of the n-type semiconductor located in the upper layer.
For example, a configuration in which the upper surface of the channel layer is covered with a different oxide semiconductor may be employed.
Alternatively, for example, a stacked structure in which a microcrystalline (close to amorphous) oxide semiconductor is stacked over a crystalline n-type oxide semiconductor may be employed. Here, the microcrystal refers to a microcrystalline oxide semiconductor film obtained by heat-treating an amorphous oxide semiconductor formed with a sputtering apparatus in a range of 180 ° C. to 450 ° C., for example. Alternatively, it refers to a microcrystalline oxide semiconductor film formed with the substrate temperature at the time of film formation set to around 200 ° C. The microcrystalline oxide semiconductor film is an oxide semiconductor film in which crystal grains of at least about 1 nm to about 3 nm or larger than 3 nm can be observed by an observation method such as TEM.
An oxide semiconductor can be improved in carrier mobility and reliability by being changed from amorphous to crystalline. The melting point as an oxide of indium oxide or gallium oxide is high. Antimony oxide and bismuth oxide have melting points of 1000 ° C. or lower, and oxides have low melting points. For example, when a ternary composite oxide of indium oxide, gallium oxide, and antimony oxide is employed, the crystallization temperature of the composite oxide can be lowered due to the effect of antimony oxide having a low melting point. In other words, an oxide semiconductor that can be easily crystallized from an amorphous state to a microcrystalline state can be provided.
As a stacked structure of the semiconductor, an n-type oxide semiconductor may be stacked over an n-type polysilicon semiconductor. As a method for obtaining a stacked structure using the polysilicon semiconductor as an underlayer, it is preferable to form an oxide semiconductor by sputtering or the like while maintaining a vacuum state after the polysilicon crystallization step by laser annealing. As an oxide semiconductor applied to this method, a complex oxide rich in zinc oxide can be used because it is required to be easily soluble in wet etching in a later step. For example, as the atomic ratio of the metal element of the target used for sputtering, In: Ga: Zn = 1: 2: 2 can be exemplified. In this stacked structure, an oxide semiconductor layer may not be stacked only on the polysilicon channel layer (for example, removed by wet etching).
Further, one thin film transistor (active element) having an n-type oxide semiconductor channel layer and one thin film transistor (active element) having an n-type silicon semiconductor channel layer are provided in the same pixel, and each channel layer of the thin film transistor It is also possible to drive a display function layer such as a liquid crystal layer or an OLED so that the above characteristics can be utilized. When a liquid crystal layer or an OLED is used as the display function layer, an n-type polysilicon thin film transistor is adopted as a drive transistor for applying a voltage (current) to the display function layer, and an n-type oxidation transistor is used as a switching transistor for sending a signal to the polysilicon thin film transistor. A thin film semiconductor thin film transistor can be employed.

The same structure can be adopted for each of the drain electrode 26 and the source electrode 24 (source wiring 31). For example, a multilayer conductive layer can be used for the drain electrode 26 and the source electrode 24. For example, an electrode structure in which aluminum, copper, or an alloy layer thereof is sandwiched between molybdenum, titanium, tantalum, tungsten, a conductive metal oxide film, or the like can be employed. On the fourth insulating layer 14, the drain electrode 26 and the source electrode 24 may be formed first, and the channel layer 27 may be formed so as to be stacked on these two electrodes. The structure of the transistor may be a multi-gate structure such as a double gate structure.
The semiconductor layer or the channel layer may be adjusted in mobility and electron concentration in the thickness direction. The semiconductor layer or the channel layer may have a stacked structure in which different oxide semiconductors are stacked. The channel length of the transistor, which is determined by the minimum distance between the source electrode and the drain electrode, can be 10 nm to 10 μm, for example, 20 nm to 1 μm.

The third insulating layer 13 functions as a gate insulating film. Examples of such insulating film materials include hafnium silicate (HfSiOx), silicon oxide, gallium oxide, aluminum oxide, silicon nitride, silicon oxynitride, aluminum oxynitride, gallium oxide, zinc oxide, hafnium oxide, cerium oxide, and the like. A mixed insulating film or the like is employed. Cerium oxide has a high dielectric constant and a strong bond between cerium and oxygen atoms. For this reason, it is preferable that the gate insulating film is a composite oxide containing cerium oxide. Even when cerium oxide is employed as one of the oxides constituting the composite oxide, it is easy to maintain a high dielectric constant in an amorphous state. Cerium oxide has an oxidizing power. Therefore, a structure in which an oxide semiconductor and cerium oxide are in contact can avoid oxygen vacancies in the oxide semiconductor, and a stable oxide can be realized. In the configuration using nitride for the gate insulating film, the above-described effect does not appear. The material of the gate insulating film may include a lanthanoid metal silicate represented by cerium silicate (CeSiOx).

The structure of the third insulating layer 13 may be a single layer film, a mixed film, or a multilayer film. In the case of a mixed film or multilayer film, the mixed film or multilayer film can be formed of a material selected from the above insulating film materials. The film thickness of the third insulating layer 13 is a film thickness that can be selected from a range of 2 nm to 300 nm, for example. In the case where the channel layer 27 is formed using an oxide semiconductor, the interface of the third insulating layer 13 in contact with the channel layer 27 can be formed in a state where a large amount of oxygen is contained (film formation atmosphere).

In the thin film transistor manufacturing process, in a thin film transistor having a top gate structure, a gate insulating film containing cerium oxide can be formed in an introduced gas containing oxygen after forming an oxide semiconductor. At this time, the surface of the oxide semiconductor under the gate insulating film can be oxidized, and the degree of oxidation of the surface can be adjusted. In a thin film transistor having a bottom gate structure, it is difficult to adjust the degree of oxidation of the surface of the oxide semiconductor because the gate insulating film formation step is performed before the oxide semiconductor step. In a thin film transistor having a top gate structure, oxidation of the surface of the oxide semiconductor can be promoted more than in the bottom gate structure, and oxygen vacancies in the oxide semiconductor are less likely to occur.

The plurality of insulating layers including the first insulating layer 11, the second insulating layer 12, the third insulating layer 13, and the insulating layer (fourth insulating layer 14) underlying the oxide semiconductor are formed using an inorganic insulating material or an organic insulating material. Can be formed. As a material for the insulating layer, silicon oxide, silicon oxynitride, or aluminum oxide can be used. As a structure of the insulating layer, a single layer or a plurality of layers including the above materials can be used. A configuration in which a plurality of layers formed of different insulating materials are stacked may be employed. In order to obtain the effect of planarizing the upper surface of the insulating film, an acrylic resin, a polyimide resin, a benzocyclobutene resin, a polyamide resin, or the like may be used for some insulating layers. A low dielectric constant material (low-k material) can also be used.

A gate electrode 25 is disposed on the channel layer 27 via the third insulating layer 13. The gate electrode 25 (gate wiring 10) can be formed in the same process using the same material as the common wiring 30 and having the same layer structure. Further, the gate electrode 25 may be formed using the same material as the drain electrode 26 and the source electrode 24 described above so as to have the same layer structure. In the case where the gate electrode 25 is formed using a multi-layered conductive material, a configuration in which a copper layer or a copper alloy layer is sandwiched between conductive metal oxides can be employed.
The surface of the metal layer 5 exposed at the end of the gate electrode 25 can be covered with a complex oxide containing indium. Alternatively, the entire gate electrode 25 may be covered with a nitride such as silicon nitride or molybdenum nitride so as to include the end portion of the gate electrode 25. Alternatively, an insulating film having the same composition as the above-described gate insulating film may be stacked with a thickness greater than 50 nm.

As a method of forming the gate electrode 25, prior to the formation of the gate electrode 25, only the third insulating layer 13 positioned immediately above the channel layer 27 of the active element 28 is subjected to dry etching or the like, and the thickness of the third insulating layer 13 is thus determined. The thickness can be reduced.
Oxide semiconductors having different electrical properties may be further inserted at the interface of the gate electrode 25 in contact with the third insulating layer 13. Alternatively, the third insulating layer 13 may be formed of an insulating metal oxide layer containing cerium oxide or gallium oxide.
Specifically, it is necessary to increase the thickness of the third insulating layer 13 in order to prevent noise caused by the video signal supplied to the source wiring 31 from getting on the common wiring 30. On the other hand, the third insulating layer 13 has a function as a gate insulating film located between the gate electrode 25 and the channel layer 27, and requires an appropriate film thickness considering the switching characteristics of the active element 28. Is done. In order to realize the two contradictory functions as described above, the third insulation positioned immediately above the channel layer 27 while keeping the film thickness of the third insulation layer 13 between the common wiring 30 and the source wiring 31 large. By reducing the thickness of the layer 13, noise caused by the video signal supplied to the source wiring can be prevented from entering the common wiring 30, and desired switching characteristics can be realized in the active element 28. Can do.
Further, a light shielding film may be formed below the channel layer 27. As a material for the light shielding film, a refractory metal such as molybdenum, tungsten, titanium, or chromium can be used.

The gate wiring 10 is electrically linked to the active element 28. Specifically, the gate electrode 25 connected to the gate wiring 10 and the channel layer 27 of the active element 28 face each other with the third insulating layer 13 interposed therebetween. Switching driving is performed in the active element 28 in accordance with the scanning signal supplied from the video signal control unit 121 to the gate electrode 25.

A voltage as a video signal is applied to the source wiring 31 from the video signal control unit 121. For example, a video signal having a positive or negative voltage of ± 2.5 V to ± 5 V is applied to the source wiring 31. The voltage applied to the common electrode 17 can be, for example, a range of ± 2.5 V that changes every frame inversion. Further, the potential of the common electrode 17 may be a constant potential in a range from the liquid crystal driving threshold value Vth to 0V. When this common electrode is applied to constant potential driving described later, it is desirable to use an oxide semiconductor for the channel layer 27. The channel layer composed of an oxide semiconductor has a high electrical withstand voltage, and a transistor using an oxide semiconductor applies a high drive voltage exceeding the range of ± 5 V to the electrode portion 17A, thereby speeding up the response of the liquid crystal. It is possible to Various driving methods such as frame inversion driving, column inversion (vertical line) inversion driving, horizontal line inversion driving, and dot inversion driving can be applied to the liquid crystal driving. The liquid crystal driving according to the present embodiment will be described later with reference to FIG.

When a copper alloy is used as a part of the structure of the gate electrode 25, a metal element or a metalloid element in a range of 0.1 at% or more and 4 at% or less can be added to copper. Thus, the effect that copper migration can be suppressed is obtained by adding an element to copper. In particular, elements that can be placed at the lattice position of copper by substituting a part of copper atoms in the crystal of the copper layer (grains), and the movement of copper atoms in the vicinity of the copper grains precipitated at the grain boundaries of the copper layer It is preferable to add to the copper together with an element that suppresses the above. Alternatively, in order to suppress the movement of the copper atom, it is preferable to add an element heavier than the copper atom (having a larger atomic weight) to the copper. In addition, it is preferable to select an additive element in which the conductivity of copper is less likely to decrease with an addition amount within a range of 0.1 at% to 4 at% with respect to copper. Furthermore, in consideration of vacuum film formation such as sputtering, an element whose film formation rate such as sputtering is close to copper is preferable. As described above, the technique of adding an element to copper can also be applied when copper is replaced with silver or aluminum. In other words, a silver alloy or an aluminum alloy may be used instead of the copper alloy.

Adding an element that can be placed in the copper lattice position to replace a part of the copper atoms in the crystal (grain) of the copper layer means that, in other words, a metal or metalloid that forms a solid solution with copper near room temperature. It is to be added to copper. Examples of the metal that easily forms a solid solution with copper include manganese, nickel, zinc, palladium, gallium, and gold (Au). Adding an element to copper that precipitates at the grain boundary of the copper layer and suppresses the movement of copper atoms in the vicinity of the copper grain is, in other words, adding a metal or metalloid that does not form a solid solution with copper near room temperature. That is. There are various materials for metals and metalloids that are difficult to form a solid solution with copper or that are difficult to form a solid solution with copper. For example, refractory metals such as titanium, zirconium, molybdenum, and tungsten, and elements called semimetals such as silicon, germanium, antimony, and bismuth can be used.
Copper has a problem in reliability from the viewpoint of migration. Reliability can be supplemented by adding the above metals and metalloids to copper. The effect of suppressing migration can be obtained by adding 0.1 at% or more of the above metal or metalloid to copper. However, when the above metal or metalloid is added in excess of 4 at% to copper, the conductivity of copper is significantly deteriorated, and the merit of selecting copper or a copper alloy cannot be obtained.

As the conductive metal oxide, for example, a composite oxide (mixed oxide) selected from two or more of indium oxide, tin oxide, zinc oxide, and antimony oxide can be employed. Further, a small amount of titanium oxide, zirconium oxide, aluminum oxide, magnesium oxide, and germanium oxide may be added to this composite oxide. A composite oxide of indium oxide and tin oxide is generally used as a low resistance transparent conductive film called ITO. In the case of using a ternary composite oxide of indium oxide, zinc oxide, and tin oxide, the etching rate in wet etching can be adjusted by adjusting the mixing ratio of zinc oxide and tin oxide. In the three-layer configuration in which the alloy layer is sandwiched between ternary complex oxides of indium oxide, zinc oxide, and tin oxide, the etching rate of the complex oxide and the etching rate of the copper alloy layer can be adjusted, The pattern widths of these three layers can be made substantially equal.

Generally, in order to perform gradation display, various voltages corresponding to gradation display are applied to the source wiring, and video signals are applied to the source wiring at various timings. Such noise caused by the video signal is likely to get on the common electrode 17 and may reduce the detection accuracy of touch sensing. Therefore, as shown in FIG. 5, by adopting a structure in which the distance W2 between the source wiring 31 and the touch sensing wiring 3 is increased, an effect that noise can be reduced is obtained.

In the present embodiment, as the active element 28, a transistor having a top gate structure is employed. Instead of the top gate structure, a transistor having a bottom gate structure may be employed. However, in the case of employing a top gate structure transistor, the position of the source wiring 31 in the Z direction may be separated from the touch sensing wiring 3. it can. In other words, in the case of a transistor having a top gate structure, the source wiring can be separated from the space where the electrostatic capacitance is generated between the touch sensing wiring 3 and the common electrode 17. By separating the source wiring from the space where the electrostatic capacitance is generated in this way, the influence of noise on the touch signal detected between the touch sensing wiring 3 and the common electrode 17, that is, various types generated from the source wiring. The influence of noise caused by the video signal on the touch signal can be reduced. In the present embodiment, it is important that the physical space between the touch sensing wiring 3 and the common electrode 17 does not include the source wiring 31 and the pixel electrode 20. In the following description, a physical space between the touch sensing wiring 3 and the common electrode 17 may be referred to as a touch sensing space. Further, it is desirable to form a touch sensing space that takes into account the distance W4 between the gate wiring 10 and the common wiring 30 (conductive wiring) illustrated in FIG. 13 and the above-described distance W2. By obtaining the distance W4, it is possible to reduce the influence of noise caused by the gate signal supplied to the gate wiring 10 on the common wiring 30.

(Specific structure of display device substrate 100)
Next, a specific structure of the display device substrate 100 will be described with reference to FIGS. FIG. 6 is a plan view partially showing the liquid crystal display device LCD1 according to the first embodiment of the present invention, as viewed from the observer side through the transparent substrate 21. FIG.
FIG. 7 is a sectional view partially showing the display device substrate 100 according to the first embodiment of the present invention, and is a sectional view taken along the line FF ′ shown in FIG. FIG. 8 is a cross-sectional view partially illustrating the display device substrate 100 according to the first embodiment of the present invention, and is a cross-sectional view illustrating the terminal portion 34 of the touch sensing wiring 3. FIG. 9 is a cross-sectional view partially showing the display device substrate 100 according to the first embodiment of the present invention, and is a cross-sectional view illustrating the terminal portion 34 of the touch sensing wiring 3.
As shown in FIG. 6, the display device substrate 100 is laminated on the array substrate 200 shown in FIG. 2 via a liquid crystal layer. Thus, a liquid crystal display device LCD1 in which the display device substrate 100 is bonded to the array substrate 200 via the liquid crystal layer 300 is obtained.
In FIG. 6, the source wiring 31 and the common wiring 30 constituting the array substrate 200 are shown, and other members (electrodes, wirings, active elements, etc.) constituting the array substrate 200 are omitted. .

The display device substrate 100 includes a color filter 51 (RGB), a touch sensing wiring 3, and a black matrix BM. The black matrix BM has a lattice pattern having a plurality of pixel openings. Each of the plurality of pixel openings is provided with a red filter (R), a green filter (G), and a blue filter (blue) constituting the color filter 51. The black matrix BM has an X direction extending portion extending in the X direction and a Y direction extending portion extending in the Y direction, and is formed of the material constituting the black layer 8 described above. . Further, the Y-direction extending portion corresponds to the black layer 8. The touch sensing wiring 3 is provided on the display device substrate 100 so as to overlap the Y-direction extending portion (a part of the black matrix) of the black matrix BM (see FIG. 7).
Further, the touch sensing wiring 3 is formed on the black matrix BM and is extended in the Y direction. In the positional relationship between the display device substrate 100 and the array substrate 200 in plan view, the touch sensing wiring 3 is disposed so as to overlap the source wiring 31, and the extending direction of the touch sensing wiring 3 is the same as that of the common wiring 30. It is orthogonal to the extending direction.

As shown in FIG. 7, on the black layer 8 constituting the black matrix BM, the touch sensing wiring 3 having a three-layer structure including a first conductive metal oxide layer, a copper alloy layer, and a second conductive metal oxide layer. Are stacked.
As a material for the conductive metal oxide layer, a conductive metal oxide based on indium oxide or tin oxide can be used. For example, a composite oxide obtained by adding zinc oxide, tin oxide, titanium oxide, zirconium oxide, magnesium oxide, aluminum oxide, germanium oxide, gallium oxide, cerium oxide, antimony oxide, or the like to indium oxide can be used. At least in the case of using a composite oxide system in which zinc oxide is mixed, the etching rate in wet etching can be adjusted according to the amount of zinc oxide, antimony oxide, and gallium oxide added to indium oxide.

Touch sensing wiring or conductive wiring of the three-layer configuration of the first conductive metal oxide layer, the copper alloy layer, and the second conductive metal oxide layer as described above (common wiring 30 formed on the array substrate 200). When forming the film, it is important to match the etching rates of the conductive metal oxide and the copper alloy and perform etching with substantially the same width. By adding a binary system material of indium oxide and zinc oxide as a main material, and adding other necessary elements, for example, other metal oxides capable of improving conductivity and reliability to the main material, the above 3 Wiring having a layer structure can be realized.
For example, a composite oxide of a composite metal oxide such as indium oxide-zinc oxide-tin oxide has high conductivity and strong adhesion to a copper alloy, a color filter, a glass substrate, and the like. Further, this composite metal oxide is also a hard ceramic, and a good ohmic contact can be obtained in an electrical mounting structure. When the conductive metal oxide layer containing such a composite oxide is applied to a three-layer configuration of the first conductive metal oxide layer, the copper alloy layer, and the second conductive metal oxide layer, for example, Extremely strong electrical mounting can be performed on a glass substrate.

As shown in FIG. 7, on the black matrix BM, a second conductive metal oxide layer 4 that is a ternary mixed oxide film (conductive metal oxide layer) containing indium oxide, zinc oxide, and tin oxide, By continuously forming the metal layer 5 and the first conductive metal oxide layer 6 similar to the second conductive metal oxide layer 4, three layers can be formed. As the film formation apparatus, for example, a sputtering apparatus is used, and continuous film formation is performed while maintaining a vacuum atmosphere.
For example, in each of the second conductive metal oxide layer 4 and the first conductive metal oxide layer 6, the composition of the metal layer made of indium oxide, zinc oxide, tin oxide, and copper alloy is as follows. is there. In either case, the atomic percentage of the metal element in the mixed oxide is a count of only the metal element that does not count the oxygen element.
First conductive metal oxide layer; In: Zn: Sn => 90: 8: 2
Second conductive metal oxide layer; In: Zn: Sn ⇒ 91: 7: 2
-Metal layer; Cu: Zn: Sb ⇒ 98.6: 1.0: 0.4
The amount of indium (In) contained in the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 needs to be greater than 80 at%. The amount of indium (In) is preferably greater than 80 at%. More preferably, the amount of indium (In) is greater than 90 at%. When the amount of indium (In) is less than 80 at%, the specific resistance of the conductive metal oxide layer formed is not preferable. If the amount of zinc (Zn) exceeds 20 at%, the alkali resistance of the conductive metal oxide (mixed oxide) decreases, which is not preferable.
The amount of zinc (Zn) contained in the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 needs to be larger than the amount of tin (Sn). If the tin content exceeds the zinc content, there will be problems with wet etching in the subsequent process. In other words, the metal layer made of copper or copper alloy is more easily etched than the conductive metal oxide layer, and the first conductive metal oxide layer 6, the metal layer 5, and the second conductive metal oxide layer 4. A difference in the width is likely to occur.
The amount of tin (Sn) contained in the first conductive metal oxide layer 6 and the second conductive metal oxide layer 4 is preferably in the range of 0.5 at% or more and 6 at% or less. In comparison with indium element, by adding tin of 0.5 at% or more and 6 at% or less to the conductive metal oxide layer, a ternary mixed oxide film of indium, zinc, and tin (conductive composite) The specific resistance of the oxide layer can be reduced. If the amount of tin exceeds 7 at%, zinc is also added to the conductive metal oxide layer, so that the specific resistance of the ternary mixed oxide film (conductive composite oxide layer) becomes too large. By adjusting the amount of zinc and tin within the above range (0.5 at% or more and 6 at% or less), and adjusting the film forming conditions and annealing conditions, the specific resistance is approximately mixed oxide film. The specific resistance of the single layer film can fall within a small range of 5 × 10 ⁻⁴ Ωcm or more and 3 × 10 ⁻⁴ Ωcm or less. A small amount of other elements such as titanium, zirconium, magnesium, aluminum, and germanium can be added to the mixed oxide.

The black matrix BM has a frame area surrounding a matrix area (rectangular display area and display screen) on the display surface (display unit 110). It is preferable that the touch sensing wiring 3 is formed on the transparent substrate 21 so as to extend from the frame region toward the outside of the transparent substrate 21, and the terminal portion 34 is formed on the touch sensing wiring 3 positioned outside the frame region. In this case, the terminal portion 34 of the touch sensing wiring 3 is provided at a position extending from the frame area without overlapping with the black matrix BM. In this configuration, the terminal portion 34 used for mounting can be directly formed on the glass surface of the transparent substrate 21 that is a glass plate.
FIG. 8 is a cross-sectional view showing the touch sensing wiring 3 extending from the black matrix BM in the frame region toward the outside of the transparent substrate 21 and is a view along the X direction. The terminal part 34 of the touch sensing wiring 3 is directly disposed on the transparent substrate 21 which is a glass plate. FIG. 9 is a cross-sectional view showing the terminal portion 34 and is a view along the Y direction.

The shape of the terminal portion in plan view is not limited to FIGS. For example, after covering the terminal portion 34 with the transparent resin layer 16, the upper portion of the terminal portion 34 is removed by a method such as dry etching to form a terminal portion 34 having a circular or rectangular shape, and the surface of the terminal portion 34. The conductive metal oxide layer may be exposed. In this case, the transfer of transfer from the display device substrate 100 to the array substrate 200 is performed in the thickness direction of the seal portion in the seal portion for bonding the display device substrate 100 and the array substrate 200 or in the liquid crystal cell. It is also possible. By disposing a conductor selected from an anisotropic conductive film, a minute metal sphere, or a resin sphere covered with a metal film in the seal portion, the display device substrate 100 and the array substrate 200 can be electrically connected.

In the conductive structure between the display device substrate 100 and the array substrate 200, the first conductive metal oxide layer 6, the copper alloy layer (metal layer 5), and the second conductive metal oxide are provided only on the display device substrate 100. Instead of disposing the three layers 4, the array substrate 200 is similarly formed of three layers of the first conductive metal oxide layer, the copper alloy layer, and the second conductive metal oxide layer. It is preferable to form a terminal portion. The terminals formed on the array substrate 200 in this way are used as terminals for transfer of transfer (transfer) to the display device substrate 100. Specifically, either the structure of the layer of the conductive layer constituting the gate wiring 10 formed on the array substrate 200 or the structure of the layer of the conductive layer constituting the source wiring 31 is changed to the first conductive metal. A three-layer structure of an oxide layer, a copper alloy layer, and a second conductive metal oxide layer is formed. As a result, it is possible to form lead wirings and terminal portions for conduction between the display device substrate 100 and the array substrate 200 on the array substrate 200.

(Liquid crystal layer 300)
Returning to FIG. 3, the liquid crystal layer 300 (display function layer) will be described.
The liquid crystal layer 300 includes liquid crystal molecules 39 having positive dielectric anisotropy. The initial alignment of the liquid crystal molecules is horizontal with respect to the substrate surface of the display device substrate 100 or the array substrate 200. The liquid crystal driving according to the first embodiment using the liquid crystal layer 300 may be referred to as a horizontal electric field method because a driving voltage is applied to the liquid crystal molecules so as to cross the liquid crystal layer in plan view. The operation of the liquid crystal molecules 39 will be described later with reference to FIGS. 15 and 16. The liquid crystal constituting the liquid crystal layer 300 may be a liquid crystal having a negative dielectric anisotropy or a liquid crystal having a positive dielectric anisotropy. It is preferable that the resistivity of the liquid crystal and the alignment film used in the liquid crystal display device, and further the transparent resin layer provided on the display device substrate is high, and the resistivity of these members is preferably 1 × 10 ¹³ Ω · cm or more. .

(Manufacturing method of liquid crystal display device LCD1)
Next, a manufacturing method of the liquid crystal display device LCD1 including the array substrate 200 having the pixel structure shown in FIGS. 2 to 5 will be described with reference to FIGS.
First, the transparent substrate 22 is prepared, and the fourth insulating layer 14 is formed so as to cover the surface of the transparent substrate 22.
Next, as shown in FIG. 10, a channel layer 27 constituting the active element 28 is formed on the fourth insulating layer 14. As the material of the channel layer 27, an oxide semiconductor is employed. In the present embodiment, the channel layer 27 is patterned so that one channel layer 27 is disposed in one pixel. In FIG. 10,

broken lines

131 and 90 are shown. A broken line 131 indicates the position of the source wiring formed on the fourth insulating layer 14 after the channel layer 27 is formed. A broken line 90 indicates the position of the gate wiring formed on the third insulating layer 13 after the source wiring 31 is formed.

Next, as shown in FIG. 11, the source electrode 24 and the drain electrode 26 are formed on the channel layer 27, and the source wiring 31 that is electrically linked to the source electrode 24 is formed. The source wiring 31 has a linear pattern extending in the Y direction.

Next, the third insulating layer 13 is formed on the transparent substrate 22, that is, on the fourth insulating layer 14 so as to cover the channel layer 27, the source electrode 24, the drain electrode 26, and the source wiring 31. The third insulating layer 13 has a function as an interlayer insulating film located between two wiring layers and a function as a gate insulating film.
Next, as shown in FIG. 12, after forming the third insulating layer 13, the gate electrode 25 is formed on the third insulating layer 13 so as to coincide with the formation position of the channel layer 27. Further, simultaneously with the formation of the gate electrode 25, the gate wiring 10 and the common wiring 30 which are electrically linked to the gate electrode 25 are formed. The gate electrode 25, the gate wiring 10, and the common wiring 30 are conductive layers made of a conductive material as described above, and are formed in the same process.

Next, the second insulating layer 12 is formed on the transparent substrate 22, that is, on the third insulating layer 13 so as to cover the gate electrode 25, the gate wiring 10, and the common wiring 30. After forming the second insulating layer 12, a transparent conductive film is formed on the entire surface of the second insulating layer 12.
Thereafter, by patterning the transparent conductive film, a pixel electrode 20 is formed for each pixel as shown in FIG. When patterning the pixel electrode 20, a through hole 20S is also formed. That is, the through hole 20S is an opening from which the transparent conductive film is removed.
FIG. 13 shows a structure in which the second insulating layer 12 covering the active element 28, the source wiring 31, the gate wiring 10, the common wiring 30 and the like is formed. A pixel electrode 20 is formed on the second insulating layer 12 by patterning. The pixel electrode 20 is electrically connected to each drain electrode 26 of the active element 28 through a contact hole 29. In addition, the diameter of the through hole 20S formed in the pixel electrode 20 is larger than the diameter of the contact hole H formed in a later process. The through hole 20 S has a sufficient size (diameter) so that no electrical leakage occurs between the common electrode 17 and the common wiring 30 inside the contact hole H. FIG. 13 shows a distance W4 between the common wiring 30 and the gate wiring 10. Since the distance W4 is obtained, the structure is such that noise caused by the common wiring 30 hardly affects the gate wiring 10.

Next, the first insulating layer 11 is formed on the transparent substrate 22, that is, on the second insulating layer 12. Thereby, the first insulating layer 11 embeds the through hole 20 S and covers the entire surface of the pixel electrode 20. Thereafter, contact holes H are formed in the first insulating layer 11 and the second insulating layer 12 at positions corresponding to the through holes 20S. By etching the first insulating layer 11 and the second insulating layer 12, a plurality of contact holes H are collectively formed on the entire surface of the array substrate 200.
Thereafter, a transparent conductive film as a constituent material of the common electrode 17 is formed on the first insulating layer 11 so as to cover the contact hole H. Thereafter, by patterning the transparent conductive film, the electrode portion 17A shown in FIG. 4B is formed on the first insulating layer 11, the conductive connection portion 17B is embedded in the contact hole H, and the common electrode 17 is formed. The As a result, the common electrode 17 and the common wiring 30 are electrically connected. Through the above steps, the array substrate 200 shown in FIG. 2 is obtained.

In the example shown in FIG. 2, the common electrode 17 is formed on the first insulating layer 11 formed so as to cover the pixel electrode 20. In addition, a common electrode 17 having two stripe pattern shapes per pixel is disposed in the longitudinal direction of the pixel. The pattern shape and the number of the common electrodes 17 are not limited to this, and can be increased or decreased depending on the pixel size or the pixel size. The common electrode 17 is formed of a transparent conductive film such as ITO. The common electrode 17 is electrically connected to the common wiring 30 through the contact hole H at the center position in the longitudinal direction of the pixel. A portion where the common electrode 17 and the pixel electrode 20 overlap may be used as an auxiliary capacitor when performing liquid crystal display.

According to the manufacturing method of the liquid crystal display device LCD1 described above, it is necessary to provide a jumper line, a bypass tunnel, etc. even when the source wiring and gate wiring for driving the active element are provided on one array substrate. The liquid crystal display device LCD1 can be manufactured at a low cost.

(Time division of liquid crystal drive and touch sensing drive)
FIG. 14 is a timing chart illustrating an example of time-division driving of liquid crystal driving and touch sensing driving that can be applied to the first embodiment and embodiments described later.
Regarding the ordinal expression of the first pulse signal and the second pulse signal described below, for example, the odd number of the pulse signal Vc supplied as the clock frequency is temporarily referred to as the first pulse signal, and the even number is the second pulse signal. It merely represents a continuous signal and does not specify the pulse signal Vc.
The display period shown in FIG. 14 is a display period in which one frame is 60 Hz, for example. In this one frame period, for example, one display unit period of a pixel includes a white display period and a black display period.
White display is performed by inputting the first pulse signal which is a clock signal. Specifically, with the input of the first pulse signal, a video signal is supplied to the source line 31, and the liquid crystal driving voltage Vd is supplied to the pixel electrode 20 via the drain electrode 26. The liquid crystal driving voltage Vd is held between the pixel electrode 20 and the common electrode 17, and drives the liquid crystal layer. An active element (thin film transistor) 28 using an oxide semiconductor as a channel layer has a higher liquid crystal driving voltage holding capability than an active element using a polysilicon semiconductor as a channel layer, and can hold a high transmittance of each pixel for a long period.

Next, when the second pulse signal is input, the display shifts from white display to black display. Black display is realized, for example, by setting the voltage held between the pixel electrode 20 and the common electrode 17 to 0 V or the ground potential using the second pulse signal as a trigger. For example, the voltage of the source line is accelerated to 0 V by supplying a voltage having a polarity opposite to that of the video signal supplied to the source line in the white display period to the source line for an application time with a short pulse signal width. It becomes possible to return to. The reverse polarity voltage may be a low voltage near the threshold voltage Vth for driving the liquid crystal. In order to shift to black display, it is preferable to ground the gate wiring. In the case of an active element using a polysilicon semiconductor as the channel layer, the gate wiring 10 and the source wiring 31 may be simply grounded after the second pulse signal is input. The black display means that the liquid crystal molecules in the liquid crystal layer return to the initial alignment state and are in a crossed Nicol black state.

The touch sensing period T _touch is provided in the period of the white display stable period Wr or the black display stable period Er in which the transmittance is stable, and the touch sensing can be performed in this period. During a period in which the video signal and the gate signal are supplied to the source wiring 31 and the gate wiring 10, for example, during the application time Dt during which the voltage Vd is applied, the touch sensing wiring 3 picks up noise generated from the source wiring or the active element. It becomes easy and is not preferable.
Various liquid crystal driving methods such as frame inversion driving, column inversion driving (vertical line inversion driving), horizontal line inversion driving, and dot inversion driving can be employed in the liquid crystal display device according to the embodiment of the present invention. For each liquid crystal driving method, for example, the timing of the touch sensing period as described below can be taken.
(1) Timing after video writing with one pixel or plural pixels such as two pixels (after video display in the display unit period) (2) After video writing of one vertical line Timing (3) Timing after video writing on one horizontal line (4) Timing after video writing on 1 frame or 1/2 frame “Video writing line” from (1) to (4) The period after “break” is synonymous with the white display stabilization period Wr shown in FIG. In addition, the “after video writing” of (1) to (4) above can be replaced with a black display stabilization period Er shown in FIG. As described above, the touch sensing period may be provided in the two periods of the white display stable period Wr and the black display stable period Er.

As shown in the timing chart of FIG. 14, in the black display stabilization period Er, a high frequency touch sensing drive voltage V _touch is applied to the touch drive wiring (touch sensing wiring 3 or common wiring 30 described later).
Further, in the black display stable period Er, the light emission of the backlight unit BU such as an LED can be stopped, and the influence of noise caused by the driving of the backlight unit BU can be eliminated. The black display stabilization period can also be used as “black insertion” for reducing color misregistration in 3D display (stereoscopic image display).

In the touch sensing period T _touch , the touch drive voltage can be applied to either the touch sensing wiring 3 or the common wiring 30. In other words, when the touch sensing wiring 3 functions as a drive electrode, the common electrode 17 can function as a detection electrode. On the contrary, when the touch sensing wiring 3 functions as a detection electrode, the common electrode 17 can function as a drive electrode. That is, the functions of the drive electrode and the detection electrode can be interchanged in the touch sensing wiring 3 and the common electrode 17.
Further, in the time-division driving of the liquid crystal driving and the touch driving, a rectangular wave of the touch driving voltage V _touch is always applied to either the touch sensing wiring 3 or the common electrode 17, and the clock frequency pulse (the first pulse signal, the first pulse signal) It is possible to adopt a method in which the touch detection signal is not detected only when two pulse signals) are applied. That is, it is possible to substantially adopt a split driving method.

(Transistor using oxide semiconductor as channel layer)
For example, when a transistor (active element) using an oxide semiconductor such as IGZO having good memory characteristics or IGAO in which zinc oxide is replaced with antimony oxide is employed as the channel layer 27, the common electrode 17 is set to a constant voltage (constant potential). ), It is possible to omit an auxiliary capacitor (storage capacitor) necessary for constant voltage driving. Unlike a transistor using a silicon semiconductor, a transistor using IGZO or IGAO as the channel layer 27 has a very small leakage current. For example, a transfer including a latch unit as described in Patent Document 4 of the prior art document A circuit can be omitted and a simple wiring structure can be adopted. In addition, in the liquid crystal display device LCD1 using the array substrate 200 including a transistor using an oxide semiconductor such as IGZO as a channel layer, since the leakage current of the transistor is small, after applying a liquid crystal driving voltage to the pixel electrode 20, The voltage can be maintained and the transmittance of the liquid crystal layer 300 can be maintained.

When an oxide semiconductor such as IGZO is used for the channel layer 27, the electron mobility in the active element 28 is high. For example, a driving voltage corresponding to a required video signal can be applied to the pixel electrode in a short time of 2 msec (milliseconds) or less. 20 can be applied. For example, one frame of double speed driving (when the number of display frames per second is 120 frames) is about 8.3 msec, and for example, 6 msec can be assigned to touch sensing. A thin film transistor using an oxide semiconductor such as IGZO as the channel layer 27 has a high withstand voltage. For this reason, for example, the response of the liquid crystal can be improved by using a high voltage of 5 V or more as the liquid crystal driving voltage.
When the common electrode 17 having the transparent electrode pattern is at a constant potential, the liquid crystal drive and the touch electrode drive may not be time-division driven. The driving frequency of the liquid crystal and the driving frequency of the touch metal wiring can be made different. For example, in the active element 28 using an oxide semiconductor such as IGZO for the channel layer 27, a transistor using a polysilicon semiconductor that needs to maintain transmittance (or voltage holding) after applying a liquid crystal driving voltage to the pixel electrode 20 In contrast to this, it is not necessary to refresh the video (rewriting the video signal again) in order to maintain the transmittance, and the flicker is small. Therefore, the liquid crystal display device LCD1 employing an oxide semiconductor such as IGZO can be driven at a low frequency and driven with low power consumption.
By using the two-layer TFT array described above, it is possible to drive with low power consumption in a wide region from low frequency to high frequency.

Since an oxide semiconductor such as IGZO has a high electrical withstand voltage, the liquid crystal can be driven at a high speed with a high voltage, and can be used for 3D image display capable of 3D display. Since the active element 28 using an oxide semiconductor such as IGZO for the channel layer 27 has high memory properties as described above, flicker (flickering of display) can be achieved even when the liquid crystal driving frequency is set to a low frequency of about 0.1 Hz to about 30 Hz. ). By using the active element 28 having IGZO or IGAO as the channel layer, dot inversion driving at a low frequency and touch driving at a frequency different from the dot inversion driving are performed together, thereby achieving low power consumption and high image quality. Both video display and high-precision touch sensing can be obtained.

In addition, since the active element 28 using the oxide semiconductor for the channel layer 27 has a small leakage current as described above, the driving voltage applied to the pixel electrode 20 can be held for a long time. The source wiring 31 of the active element 28, the gate wiring 10 (auxiliary capacitance line), etc. are formed by copper wiring having a wiring resistance smaller than that of the aluminum wiring, and further, the active element is touched by using IGZO or IGAO that can be driven in a short time. It is possible to provide a sufficient period for performing sensing scanning. That is, by applying an oxide semiconductor such as IGZO to the active element, the driving time of the liquid crystal or the like can be shortened, and there is a sufficient margin for the time applied to touch sensing in the video signal processing of the entire display screen. it can. This makes it possible to detect the change in capacitance that occurs with high accuracy.
Further, by employing an oxide semiconductor such as IGZO as the channel layer 27, it is possible to substantially eliminate the influence of coupling noise in dot inversion driving and column inversion driving. This is because, in the active element 28 using an oxide semiconductor, a voltage corresponding to a video signal can be applied to the pixel electrode 20 in a very short time (for example, 2 msec), and the pixel voltage after the video signal is applied. This is because there is a high memory property to hold the signal, and no new noise is generated during the holding period utilizing the memory property, and the influence on touch sensing can be reduced.

As the oxide semiconductor, an oxide semiconductor containing two or more metal oxides of indium, gallium, zinc, tin, aluminum, germanium, antimony, and cerium can be used.
Oxide semiconductors such as IGZO and IGAO have a high energy gap. The atomic ratios of indium (In), gallium (Ga), and zinc (Zn when the number of indium atoms in Zn is 1) can be set to 1 to 5, respectively. The melting points of indium oxide, gallium oxide, and zinc oxide as metal oxides are each in the range of about 1700 ° C. to 2200 ° C. For example, antimony oxide and bismuth oxide contain the above-mentioned indium oxide, gallium oxide, and zinc oxide. In addition, in the composite oxide, antimony oxide or bismuth oxide may be used instead of gallium oxide or zinc oxide.
The concentration of a metal element such as indium or gallium in the thickness direction of the oxide semiconductor may vary. For example, the amount of gallium oxide in the oxide semiconductor may be increased near the interface between the oxide semiconductor and the insulating layer, and the amount of indium oxide may be increased at the central portion in the film thickness direction. There may be a concentration gradient of each metal element in the film thickness direction of the oxide semiconductor, and there may be a difference in carrier mobility in the film thickness direction of the oxide semiconductor.

(Liquid crystal alignment and liquid crystal drive)
15 and 16 are plan views partially showing pixels of the liquid crystal display device LCD1 according to the first embodiment of the present invention. In order to easily explain the alignment of the liquid crystal molecules 39, the alignment state of the liquid crystal in one pixel is shown. FIG. 15 is a plan view partially showing a pixel of the liquid crystal display device LCD1 and showing a liquid crystal alignment state (initial alignment state) in one pixel. FIG. 16 is a plan view partially showing a pixel of the liquid crystal display device LCD1 and showing a liquid crystal drive operation when a liquid crystal drive voltage is applied between the pixel electrode 20 and the common electrode 17. FIG. .
In the example shown in FIGS. 15 and 16, the pixel electrode 20 is formed in a rectangular shape, and the longitudinal direction of the pixel electrode 20 coincides with the Y direction. An alignment process is performed on the alignment film so that the liquid crystal molecules 39 of the liquid crystal layer 300 are inclined at an angle θ with respect to the extending direction (Y direction) of the rectangular pixel electrode 20.

In particular, in the present embodiment, each pixel is divided into two regions, that is, each pixel has an upper region Pa (first region) and a lower region Pb (second region). The upper region Pa and the lower region Pb are arranged symmetrically with respect to the pixel center CL (a center line parallel to the X direction). The upper region Pa and the lower region Pb give a pretilt of an angle θ to the liquid crystal molecules 39 of the liquid crystal layer 300 in the Y direction. In the upper region Pa, a pretilt of an angle θ is imparted to the liquid crystal molecules 39 clockwise with respect to the Y direction. In the lower region Pb, a pretilt of an angle θ is imparted to the liquid crystal molecules 39 counterclockwise with respect to the Y direction. As the alignment treatment of the alignment film, a photo-alignment treatment or a rubbing treatment can be employed. Although it is not necessary to specifically define the angle θ, for example, the angle θ may be in the range of 3 ° to 15 °.

The liquid crystal molecules 39 to which the initial alignment is given in this way are applied to the pixel electrode 20 and the common electrode 17 as shown by the arrows in FIG. 16 when a voltage is applied between the pixel electrode 20 and the common electrode 17. In the meantime, a fringe electric field is generated, the liquid crystal molecules 39 are aligned along the direction of the fringe electric field, and the liquid crystal molecules 39 are driven. More specifically, as shown in FIG. 26, a fringe electric field from the pixel electrode 20 toward the common electrode 17 is generated, the liquid crystal molecules 39 are driven along the fringe electric field, and rotate in a plan view.

FIG. 26 is a cross-sectional view partially showing the liquid crystal display device LCD1 and shows a liquid crystal driving operation when a liquid crystal driving voltage is applied between the common electrode 17 and the pixel electrode 20. FIG. In the liquid crystal driving method called FFS, the liquid crystal molecules 39 are driven by an electric field generated between the common electrode 17 and the pixel electrode 20, particularly, an electric field generated at an electrode end called a fringe. As shown in FIG. 26, the liquid crystal molecules 39 in a part R1 in the thickness direction of the liquid crystal layer 300 rotate, and the liquid crystal molecules 39 mainly contribute to the transmittance change. Accordingly, the vertical electric field driving liquid crystal such as VA which can fully utilize the liquid crystal molecules in the thickness direction of the liquid crystal layer 300 as compared with the horizontal electric field driving liquid crystal display device such as FFS with respect to the transmittance in the vertical direction seen from the observer. High transmittance can be obtained in the display device. However, since the horizontal electric field drive liquid crystal display device such as FFS has a characteristic that the viewing angle is wide, from the viewpoint of this characteristic, the liquid crystal display device LCD1 according to the present embodiment adopts the horizontal electric field drive method.

FIG. 30 is a cross-sectional view showing a conventional liquid crystal display device 250, and is a schematic diagram showing equipotential lines L2 when a liquid crystal driving voltage is applied. When there is no transparent electrode or conductive film on the transparent substrate 215 side, the equipotential line L2 passes through the transparent resin layer 213, the color filter 214, and the transparent substrate 215 and extends upward. When the equipotential line L2 is extended in the thickness direction of the liquid crystal layer 206, the effective thickness of the liquid crystal layer 206 is secured to some extent, so that the original transmittance of the lateral electric field drive type liquid crystal display device 250 can be secured. .
FIG. 31 is a cross-sectional view showing a conventional liquid crystal display device 250A, in which a counter electrode 221 is provided between the liquid crystal layer 206 and the transparent resin layer 213 in addition to the components of the liquid crystal display device 250 described above. Yes. In this case, since the equipotential line L3 does not penetrate the counter electrode 221, the shape of the equipotential line L3 is deformed from the shape of the equipotential line L2. At this time, the effective thickness of the liquid crystal layer 206 is thinner than the effective thickness of the liquid crystal layer 206 of the liquid crystal display device 250, and the luminance (transmittance) of the liquid crystal display device 250A is greatly reduced.

The liquid crystal display device LCD1 according to the present embodiment is different from the conventional liquid crystal display device shown in FIGS. In the liquid crystal display device LCD1 according to the present embodiment, the common electrode 17 is formed above the pixel electrode 20, the potential of the common electrode 17 is maintained at 0V, and a voltage is applied between the pixel electrode 20 and the common electrode 17. As a result, a fringe electric field from the pixel electrode 20 toward the common electrode 17 is generated, and the liquid crystal molecules 39 are driven by the fringe electric field.

(Touch sensing drive)
17 and 18 show a structure in the case where the touch sensing wiring 3 functions as a touch drive electrode and the common electrode 17 functions as a touch detection electrode in the liquid crystal display device LCD1 according to the first embodiment of the present invention. Show.
The following description will be made based on the structure shown in FIGS.
As described above, the roles of the touch drive electrode and the touch detection electrode can be interchanged.

FIG. 17 is a schematic cross-sectional view showing a state where an electric field is generated between the touch sensing wiring and the common electrode. FIG. It is sectional drawing which shows the change of the production | generation state of the electric field when it adjoins.
17 and 18, a touch sensing technique using the touch sensing wiring 3 and the common electrode 17 will be described. 17 and 18 show the first insulating layer 11 and the common electrode 17 constituting the array substrate 200 and the display device substrate 100 for easy understanding of the touch sensing drive, and other configurations are omitted. is doing.

As shown in FIGS. 17 and 18, the touch sensing wiring 3 and the common electrode 17 face each other in an oblique direction inclined with respect to the thickness direction of the liquid crystal layer 300. For this reason, it is possible to easily improve the contrast of the detection signal with respect to a change in the state in which the oblique electric field is generated, and to increase the S / N ratio of touch sensing (S / N ratio improvement effect) is obtained. Further, in such an arrangement in which the touch sensing wiring 3 and the common electrode 17 face each other in an oblique direction, since the overlapping portion where the touch sensing wiring 3 and the common electrode 17 overlap in a plan view is not formed, the parasitic capacitance is greatly reduced. be able to. In addition, in the configuration in which the touch detection electrode and the touch drive electrode overlap in the vertical direction of the thickness, the capacitance at the portion where the touch detection electrode and the touch drive electrode overlap with each other hardly changes. It is difficult to give contrast. For example, when the touch detection electrode and the touch drive electrode are in a parallel positional relationship on the same plane, the capacitance tends to vary non-uniformly depending on the position of a pointer such as a finger, resulting in false detection and reduced resolution. There is a fear.
In the liquid crystal display device LCD1 according to the embodiment of the present invention, as shown in FIGS. 2 and 20, the common electrode 17 functions as a detection electrode and has a length EL. The common electrode 17 and the touch sensing wiring 3 functioning as a drive electrode and the common electrode 17 which is parallel in plan view and has a length EL can ensure a sufficient and uniform capacitance.

FIG. 17 schematically shows a capacitance generation state when the touch sensing wiring 3 functions as a touch drive electrode and the common electrode 17 functions as a touch detection electrode. The touch sensing wiring 3 is supplied with a pulsed write signal at a predetermined frequency. The supply of the writing signal may be performed by time division between liquid crystal driving and touch driving. The electrostatic capacitance indicated by the electric force lines 33 (arrows) is maintained between the grounded common electrode 17 and the touch sensing wiring 3 by the write signal.

As shown in FIG. 18, when a pointer such as a finger contacts or approaches the surface of the display device substrate 100 on the viewer side, the capacitance between the common electrode 17 and the touch sensing wiring 3 changes, and this electrostatic capacitance changes. The presence or absence of a touch of a pointer such as a finger is detected based on the change in capacity.
As shown in FIG. 17 and FIG. 18, no electrode or wiring related to liquid crystal driving is provided between the touch sensing wiring 3 and the common electrode 17. Further, as shown in FIGS. 3 and 5, the source wiring 31 is separated from the touch sensing wiring 3 and the common electrode 17 (touch drive wiring and touch detection wiring). For this reason, a structure that hardly picks up noise related to liquid crystal driving is realized.

For example, in plan view, the plurality of touch sensing wires 3 extend in the first direction (for example, the Y direction) and are arranged in the second direction (for example, the X direction). The plurality of common wirings 30 (conductive wirings) are positioned below the pixel electrodes 20 inside the array substrate 200 in the Z direction, extend in the second direction (for example, the X direction), and extend in the first direction (for example, for example) In the Y direction). The common electrode 17 is electrically connected to the common wiring 30, and a change in capacitance between the common electrode 17 and the touch sensing wiring 3 is used for detecting the presence or absence of touch.

In the liquid crystal display device LCD1 according to the present embodiment, a rectangular wave pulse signal is applied between the touch sensing wiring 3 and the common electrode 17 at a frequency of, for example, 500 Hz to 500 KHz. Normally, the common electrode 17 as the detection electrode maintains a constant output waveform by the application of the pulse signal. When a pointer such as a finger contacts or approaches the surface of the display device substrate 100 on the viewer side, a change appears in the output waveform of the common electrode 17 at that portion, and the presence or absence of a touch is determined. The distance to the display surface of the pointer such as a finger can be measured by the time from the proximity of the pointer to contact (usually several hundred μsec or more and several msec or less), the number of output pulses counted within that time, and the like. Stable touch detection can be performed by taking the integral value of the touch detection signal.

All of the touch sensing wiring 3 and the common wiring 30 (or the common electrode connected to the conductive wiring) may not be used for touch sensing. Thinning driving may be performed. Next, a case where the touch sensing wiring 3 is driven to be thinned will be described. First, all the touch sensing wires 3 are divided into a plurality of groups. The number of groups is less than the number of all touch sensing wires 3. Assume that the number of wires constituting one group is, for example, six. Here, out of all the wirings (the number of wirings is six), for example, two wirings are selected (the number smaller than the number of all the wirings, two <6). In one group, touch sensing is performed using two selected wirings, and the potentials of the remaining four wirings are set to floating potentials. Since the liquid crystal display device LCD1 has a plurality of groups, touch sensing can be performed for each group in which the wiring function is defined as described above. Similarly, thinning driving may be performed on the common wiring 30 as well.
A pointer used for touching is a finger and a pen is different in the area and capacity of a pointer that is in contact with or close to the pointer. The number of wires to be thinned out can be adjusted by such a large pointer. A pointer with a thin tip such as a pen or a needle tip can reduce the number of thinned wires and use a high-density touch sensing wiring matrix. Even during fingerprint authentication, a high-density touch sensing wiring matrix can be used.

As described above, by performing touch sensing drive for each group, the number of wires used for scanning or detection is reduced, so that the touch sensing speed can be increased. Further, in the above example, the number of wirings constituting one group is six. However, for example, one group is formed with the number of wirings of 10 or more, and two wirings selected in one group are connected. Touch sensing may be used. That is, the number of thinned-out wirings (the number of wirings having a floating potential) is increased, thereby reducing the density of selected wirings used for touch sensing (the density of selected wirings with respect to the total number of wirings). By performing detection, it contributes to reduction of power consumption and improvement of touch detection accuracy. Conversely, by reducing the number of thinned lines, increasing the density of selected lines used for touch sensing, and performing scanning or detection using the selected lines, it can be used for, for example, fingerprint authentication or touch pen input. During such touch sensing, the source wiring 31 and the gate wiring 10 can be grounded or opened (floating) to reduce parasitic capacitance caused by these wirings.

● Touch sensing drive and liquid crystal drive can be performed in a time-sharing manner. The frequency of touch driving may be adjusted according to the required speed of touch input. The touch drive frequency can be higher than the liquid crystal drive frequency. The timing at which a pointer such as a finger contacts or approaches the surface of the display device substrate 100 on the viewer side is irregular and short, so that the touch drive frequency is preferably high.

There are several methods for making the touch drive frequency different from the liquid crystal drive frequency. For example, in normally-off liquid crystal driving, the backlight may be turned off during black display (off), and touch sensing may be performed during this black display period (a period that does not affect liquid crystal display). In this case, various touch drive frequencies can be selected.
Even when a liquid crystal having negative dielectric anisotropy is used, it is easy to select a touch drive frequency different from the liquid crystal drive frequency. In other words, as shown in FIGS. 17 and 18, the electric lines of force 33 generated from the touch sensing wiring 3 toward the common electrode 17 act in an oblique direction or a thickness direction of the liquid crystal layer 300, but have different negative dielectric constants. If liquid crystal having directionality is used, the liquid crystal molecules do not rise in the direction of the electric force lines 33, so that the influence on the display quality is reduced.
Furthermore, when the wiring resistance of the touch sensing wiring 3 or the common wiring 30 is lowered and the touch driving voltage is lowered as the resistance decreases, a touch driving frequency different from the liquid crystal driving frequency can be easily set. By using a metal or alloy having good conductivity such as copper or silver for the metal layer constituting the touch sensing wiring 3 or the common wiring 30, a low wiring resistance can be obtained.

In the case of a display device that performs 3D (stereoscopic video) display, a plurality of video signals (for example, for the right eye) are displayed in order to display a three-dimensional front image or a deep image in addition to a normal two-dimensional image display. A video signal and a video signal for the left eye). For this reason, with respect to the liquid crystal driving frequency, for example, high-speed driving such as 240 Hz or 480 Hz and many video signals are required. At this time, the merit obtained by making the touch drive frequency different from the liquid crystal drive frequency is great. For example, according to the present embodiment, high-speed and high-accuracy touch sensing is possible in a 3D display game device. This embodiment is particularly useful for a display with a high touch input frequency such as a finger of a game machine or an automatic teller machine.

として Rewriting operations using video signals of pixels are frequently performed, typically in moving image display. Since the noise accompanying these video signals is derived from the source wiring, it is preferable to move the position of the source wiring 31 in the thickness direction (Z direction) away from the touch sensing wiring 3 as in the embodiment of the present invention. According to the embodiment of the present invention, since the touch drive signal is applied to the touch sensing wiring 3 located far from the source wiring 31, a structure in which a wiring to which the touch drive signal is applied is provided on the array substrate is disclosed. Therefore, the influence of noise is less than that of Patent Document 6.

Generally, the liquid crystal drive frequency is 60 Hz or a drive frequency that is an integral multiple of this frequency. Usually, the touch sensing part is affected by noise associated with the liquid crystal driving frequency. Furthermore, a normal household power supply is an AC power supply of 50 Hz or 60 Hz, and the touch sensing part easily picks up noise generated from an electric device that operates with such an external power supply. Therefore, by adopting a frequency different from the frequency of 50 Hz or 60 Hz or a frequency slightly shifted from an integer multiple of these frequencies as the frequency of touch driving, the influence of noise generated from liquid crystal driving or external electronic devices can be reduced. It can be greatly reduced. Alternatively, the application timing of the touch sensing drive signal may be shifted from the application timing of the liquid crystal drive signal on the time axis. The shift amount may be a slight amount, for example, a shift amount of ± 3% to ± 17% from the noise frequency. In this case, interference with noise frequencies can be reduced. For example, a different frequency that does not interfere with the liquid crystal driving frequency and the power supply frequency can be selected as the frequency of the touch driving, for example, from the range of 500 Hz to 500 KHz. By selecting a different frequency that does not interfere with the liquid crystal drive frequency and the power supply frequency as the touch drive frequency, for example, the influence of noise such as coupling noise in column inversion drive can be reduced.
Further, in the touch sensing drive, the power consumption in the touch sensing can be reduced by detecting the touch position by the thinning drive as described above, instead of supplying the drive voltage to all of the touch sensing wires 3.

In thinning driving, wiring that is not used for touch sensing, that is, wiring having a floating pattern, may be switched to a detection electrode or a driving electrode by a switching element to perform high-definition touch sensing. Alternatively, the wiring having the floating pattern can be switched so as to be electrically connected to the ground (grounded to the housing). In order to improve the S / N ratio of touch sensing, the signal wiring of an active element such as a TFT may be temporarily grounded to a ground (a housing or the like) when a touch sensing signal is detected.

In addition, touch sensing wiring that requires time to reset the capacitance detected by touch sensing control, that is, touch sensing wiring having a large time constant (product of capacitance and resistance) in touch sensing, for example, touches on odd rows Alternatively, the sensing wiring and the touch sensing wiring in the even-numbered rows may be alternately used for sensing to perform driving with the time constant adjusted. A plurality of touch sensing wirings may be grouped for driving and detection. The grouping of the plurality of touch sensing wires may not be line sequential but may be a collective detection method called a self detection method for each group. Parallel driving may be performed in units of groups. Alternatively, in order to cancel noise such as parasitic capacitance, a difference detection method that takes a difference between detection signals of touch sensing wirings close to or adjacent to each other may be employed.

According to the first embodiment described above, it is possible to provide the liquid crystal display device LCD1 that has a high S / N ratio, a high resolution, and that can respond to high-speed touch input. Further, by using a thin film transistor including an oxide semiconductor as a channel layer, a liquid crystal display device with low power consumption, less flicker, and a touch sensing function can be realized.

(Modification of the first embodiment)
FIG. 19 is an enlarged cross-sectional view showing a main part of a liquid crystal display device according to a modification of the first embodiment of the present invention. In FIG. 19, the same members as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.
In FIG. 19, the third insulating layer 13 formed on the array substrate 200, the protruding portion 13A formed on the third insulating layer 13, and the common wiring 30 formed on the protruding portion 13A are shown. Other insulating layers, wirings, electrodes, etc. are omitted. The protruding portion 13A is formed using, for example, the insulating material for forming the insulating layer described above.
In a plan view, the pattern of the protrusion 13A and the pattern of the common wiring 30 match. The height between the upper surface of the protrusion 13A and the upper surface of the third insulating layer 13 where the protrusion 13A is not formed is W3. As a method of forming the protrusion 13A, after forming the third insulating layer 13 according to the above-described embodiment, the protrusion 13A is additionally formed on the third insulating layer 13 previously formed on the fourth insulating layer 14. The method of providing in is mentioned. A known film forming process or patterning process is used as a method for forming such a protrusion 13A. The material of the third insulating layer 13 and the material of the protrusion 13A may be the same or different.

From the viewpoint of suppressing noise caused by the video signal supplied to the source wiring 31 from getting on the common wiring 30, it is possible to appropriately set the height W3 of the protruding portion 13A.
In particular, as shown in FIG. 5, the third insulating layer 13 functions as a gate insulating film located between the gate electrode 25 and the channel layer 27, and has an appropriate film thickness considering the switching characteristics of the active element 28. Required. For this reason, in consideration of both the suppression of noise caused by the video signal supplied to the source wiring on the common wiring 30 and the realization of a desired switching characteristic in the active element 28, the fourth insulation. It is necessary to partially vary the film thickness of the third insulating layer 13 on the layer 14.
Therefore, first, the third insulating layer 13 is formed on the fourth insulating layer 14 with an appropriate film thickness considering the switching characteristics of the active element 28, and then the height W3 considering the influence of noise on the common wiring 30. A protrusion 13 A is formed on the third insulating layer 13. Further, the common wiring 30 is formed on the protruding portion 13A. According to this configuration, the thickness of the insulator between the common wiring 30 and the source wiring 31 (the sum of the thickness of the third insulating layer 13 and the thickness of the protruding portion 13A) is maintained large, and the channel layer 27 is maintained. The thickness of the third insulating layer 13 located immediately above can be reduced. As a result, it is possible to suppress the noise caused by the video signal supplied to the source wiring from getting on the common wiring 30 and to realize desired switching characteristics in the active element 28.

(Second Embodiment)
A liquid crystal display device LCD2 according to the second embodiment will be described with reference to FIGS. The same members as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted or simplified.
FIG. 20 is a plan view partially showing the array substrate 200 constituting the liquid crystal display device LCD2 according to the second embodiment of the present invention, and is a plan view seen from the observer side.
FIG. 21 is a cross-sectional view partially showing the array substrate 200 constituting the liquid crystal display device LCD2 according to the second embodiment of the present invention, and is a cross-sectional view taken along the line DD ′ shown in FIG.
FIG. 22 is a plan view partially showing a liquid crystal display device LCD2 according to the second embodiment of the present invention. The display device includes a color filter and touch sensing wiring on the array substrate 200 via a liquid crystal layer. It is a top view which shows the structure where the board | substrate was laminated | stacked, and is the top view seen from the observer side.
FIG. 23 is a sectional view partially showing the array substrate 200 constituting the liquid crystal display device LCD2 according to the second embodiment of the present invention, and is a sectional view taken along the line EE ′ shown in FIG.
FIG. 24 is a plan view partially showing a pixel of the liquid crystal display device LCD2 according to the second embodiment of the present invention, and is a plan view showing the alignment state of the liquid crystal in one pixel.
FIG. 25 is a plan view partially showing a pixel of the liquid crystal display device LCD2 according to the second embodiment of the present invention, in which a liquid crystal driving voltage is applied when a liquid crystal driving voltage is applied between the pixel electrode and the common electrode. It is a top view which shows operation | movement.

As shown in FIG. 20, the pixels included in the liquid crystal display device LCD2 according to the second embodiment have a dog-legged pattern.
As shown in FIGS. 24 and 25, the common electrode 17 and the pixel electrode 20 have an inclined portion inclined at an angle θ with respect to the Y direction. Specifically, the common electrode 17 and the pixel electrode 20 in each pixel have an upper region Pa (first region) and a lower region Pb (second region). The upper region Pa and the lower region Pb are arranged line-symmetrically with respect to the pixel center (a center line parallel to the X direction). In the upper region Pa, the common electrode 17 and the pixel electrode 20 are inclined at an angle θ clockwise with respect to the Y direction. In the lower region Pb, the common electrode 17 and the pixel electrode 20 are inclined at an angle θ counterclockwise with respect to the Y direction. By tilting the common electrode 17 and the pixel electrode 20 in this manner, the alignment film is subjected to a rubbing process along the alignment processing direction Rub parallel to the Y direction, thereby giving the liquid crystal molecules 39 initial alignment in the Y direction. be able to. As the alignment treatment of the alignment film, a photo-alignment treatment or a rubbing treatment can be employed. Although it is not necessary to specifically define the angle θ, for example, the angle θ may be in the range of 3 ° to 15 °. In FIG. 20, the common electrode 17 is formed with a stripe pattern, and has two electrode portions 17A formed in a dogleg shape. The contact hole H is located at the center of the conductive pattern of the common electrode 17 (electrode part 17A, a dogleg-shaped pattern).

As shown in FIG. 22, the source line 31, the black layer 8 (the Y-direction extension part of the black matrix BM), the touch sensing line 3, and the red filter (R), the green filter (G) constituting the color filter 51, The blue filter (blue) also has a dog-legged pattern.

In the example shown in FIG. 23, a channel layer 27, a source electrode 24, and a drain electrode 26 are formed on the fourth insulating layer 14. In the first embodiment, the source electrode 24 and the drain electrode 26 are formed on the channel layer 27 (FIG. 11), but in the present embodiment, the channel layer 27 is formed on the source electrode 24 and the drain electrode 26. ing.
That is, in the present embodiment, the source electrode 24 and the drain electrode 26 are formed on the fourth insulating layer 14 in advance. As a configuration of the source electrode 24 and the drain electrode 26 in the second embodiment, a three-layer configuration of molybdenum / aluminum alloy / molybdenum was adopted. A part of the channel layer 27 overlaps with the source electrode 24 and the drain electrode 26. As the material of the channel layer 27, a composite oxide semiconductor of indium oxide, gallium oxide, and zinc oxide is employed. Zinc oxide can be replaced by antimony oxide.

Next, the merit that the pixel shape has the above shape will be described with reference to FIGS.
FIG. 25 shows a liquid crystal driving operation when a liquid crystal driving voltage is applied between the common electrode 17 and the pixel electrode 20. The liquid crystal driving voltage is applied in the direction of the arrow from the pixel electrode 20 to the common electrode 17, and a fringe electric field from the pixel electrode 20 toward the common electrode 17 is generated as shown in FIG. Rotate along the arrow direction in plan view. The liquid crystal molecules 39 located in the upper region Pa of the pixel and the lower region Pb of the pixel rotate in opposite directions as shown in FIG. Specifically, the liquid crystal molecules 39 in the upper region Pa rotate counterclockwise, and the liquid crystal molecules 39 in the lower region Pb rotate clockwise. Therefore, optical compensation can be realized, and the viewing angle of the liquid crystal display device LCD2 can be widened.

In the present embodiment, as the liquid crystal molecules 39, liquid crystal molecules having positive dielectric anisotropy are employed. When liquid crystal molecules having negative dielectric anisotropy are employed, the liquid crystal molecules are unlikely to rise in the thickness direction of the liquid crystal layer 300. In the present embodiment, the touch drive voltage is applied in a direction from the touch sensing wiring 3 toward the common electrode 17, that is, in an oblique direction inclined with respect to the thickness direction of the liquid crystal. It is preferable to employ liquid crystal molecules having As the liquid crystal material, for example, a high purity material having a specific resistivity of the liquid crystal layer 300 of 1 × 10 ¹³ Ωcm or more is desirable.

According to the present embodiment, in addition to the effects obtained by the first embodiment described above, by performing the alignment treatment direction Rub parallel to the Y direction, the initial alignment is performed on the liquid crystal molecules 39 in the upper region Pa and the lower region Pb. Can be granted.

With reference to FIG. 32, the merit of the present embodiment will be described more specifically.
FIG. 32 is an enlarged plan view showing one pixel of a conventional liquid crystal display device using the FFS mode, and is a plan view showing an array substrate. In FIG. 32, the pixel electrode 50 is located on the upper surface of the array substrate, and the common electrode 47 is located below the pixel electrode 50 via the insulating layer. The pixel electrode 50 and the common electrode are formed of a transparent conductive film such as ITO. The pixel electrode 50 is electrically connected to the drain electrode of the thin film transistor 46 through the contact hole 48. A contact hole 48 is disposed at a position close to the thin film transistor 46 located at the upper end portion of the pixel electrode 50.
In such a conventional liquid crystal display device, it is necessary to extend the pixel electrode 50 so as to reach the maximum distance Pd from the position of the contact hole 48. In this case, depending on the relationship between the resistance value of the transparent conductive film forming the pixel electrode 50 and the position of the pixel electrode 50, the liquid crystal molecules at a position close to the contact hole and the position away from the contact hole (the maximum distance Pd away). A difference in response occurs between the liquid crystal molecules.
A larger problem in the pixels constituting a conventional liquid crystal display device is that a liquid crystal disclination region D is generated at a position close to a contact hole of a pixel electrode formed by a plurality of stripe patterns (comb-like patterns). is there. In the disclination region D, the direction of the electric lines of force 49 from the pixel electrode 50 to the common electrode 47 changes, so that sufficient transmittance cannot be obtained, and discoloration may occur in the transmitted light.

This embodiment is different from the conventional configuration of the cooperation unit in which the pixel electrode 50 and the thin film transistor 46 are connected as shown in FIG. In this embodiment, as shown in FIG. 20, any common electrode 17 is electrically connected to the conductive wiring (common wiring 30) through a contact hole H (LH, RH) located in the center in the longitudinal direction of the pixel. Therefore, there is an advantage that the difference in resistance value of the transparent conductive film forming the common electrode 17 is smaller than that in the conventional configuration. Since the above-described conventional pixel electrode cooperation portion is not provided, the adverse effect of the liquid crystal disclination region D hardly occurs.

In the above-described embodiment, the stripe pattern or the dogleg-shaped pattern extending in the Y direction has been described as the pattern of the common electrode 17, but the present invention is not limited to this configuration. For example, a square pattern, a rectangular pattern, a parallelogram pattern, or the like may be employed.

(Third embodiment)
A liquid crystal display device LCD3 according to a third embodiment will be described with reference to FIGS.
The same members as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted or simplified.
FIG. 27 is a plan view partially showing an array substrate of a liquid crystal display device according to a third embodiment of the present invention. FIG. 28 is a plan view partially showing a display device according to a third embodiment of the present invention, in which a display device substrate having a color filter and touch sensing wiring is laminated on an array substrate via a liquid crystal layer. It is a top view which shows the made structure, and is the top view seen from the observer side. FIG. 29 is a cross-sectional view partially showing an array substrate constituting a display device according to the third embodiment of the present invention.

The pixel openings 18 in the third embodiment are formed in parallelogram shapes with different angles in plan view, and are arranged in the Y direction. Each of the pixels is divided into a matrix by gate wirings 10 parallel to the X direction and source wirings 31 along the parallelogram-shaped pixels. In FIG. 27, an active element 28 is provided at the upper right end of each pixel opening 18. The active element 28 includes a source electrode 24 connected to the source wiring 31, a channel layer 27, a drain electrode 26, and a gate electrode 25 disposed to face the channel layer 27 via an insulating film. The gate electrode 25 of the active element 28 constitutes a part of the gate wiring 10 and is connected to the gate wiring 10. Note that the structure of the active element which is a thin film transistor is the same as the structure shown in FIG.

The pixel electrode 20 is electrically connected to the drain electrode 26 through a contact hole 29 located at the upper right corner of the pixel electrode 20 as shown in FIG.
The common electrode 17 has a stripe pattern. Specifically, the common electrode 17 extends in parallel to an extending direction (a direction inclined at an angle θ with respect to the Y direction) of the pixel having a parallelogram shape in the Y direction. Located in the center.
One common electrode 17 is provided for each pixel. The angle θ is an inclination with respect to the Y direction in plan view. In each lower part of the common electrode 17, a pixel electrode 20 located in a lower part of the first insulating layer 11 in a cross-sectional view is provided. A third contact hole 43H is provided in the center of the common electrode 17 in the Y direction. The common electrode 17 is connected to the common wiring 30 (conductive wiring) through the third contact hole 43H.
In the present embodiment, each pixel is provided with one common electrode 17, and the number of third contact holes 43H is one in each pixel. In order to distinguish from the first contact hole LH and the second contact hole RH described in the first embodiment and the second embodiment, in the third embodiment, a contact hole in which the common electrode 17 and the common wiring 30 are electrically connected is a third. This is referred to as contact hole 43H. Similarly to the second embodiment, the angle θ can be set to an angle of 3 ° to 15 °, for example.

The liquid crystal molecules are aligned parallel to the plane on which the common electrode 17 or the pixel electrode 20 is provided, and the major axis direction is aligned parallel to the Y direction. This is so-called FFS mode liquid crystal drive driven by a liquid crystal drive voltage applied between the common electrode 17 and the pixel electrode 20.
Touch sensing is performed by detecting a change in capacitance between the touch sensing wiring 3 and the common electrode 17. Either the touch sensing wiring 3 or the common electrode 17 can be used as a touch drive electrode, and either can be used as a touch detection electrode.

FIG. 29 shows the distance W 1 between the touch sensing wiring 3 and the common electrode 17. In other words, the distance W1 is a distance in the Z direction in a space including the transparent resin layer 16, the color filter 51 (RGB), the alignment film (not shown), and the liquid crystal layer 300. This space does not include active elements, source lines, and pixel electrodes. In the present embodiment, this space indicated by the distance W1 is referred to as a touch sensing space.
As shown in FIG. 27, since the distance W4 between the common wiring 30 and the gate wiring 10 can be ensured, the influence of the gate signal on touch sensing can be reduced. 29, since the distance W2 between the source wiring 31 to which the video signal is supplied and the touch sensing wiring 3 can be sufficiently secured, it is possible to reduce the influence on the touch sensing caused by the noise caused by the video signal. .

The display device substrate of this embodiment includes a color filter 51 (RGB) including a black matrix, a black matrix BM, and a touch sensing wiring 3 provided on the black matrix BM on the liquid crystal layer side. In the case of multi-color display in which three types of LEDs, red LED, green LED, and blue LED, are used for the backlight unit, and the three colors are sequentially emitted by time division driving and the liquid crystal is synchronized, the color filter 51 is used. It can be omitted.

According to the present embodiment, by applying an alignment treatment direction parallel to the Y direction, different initial alignments can be imparted to the liquid crystal molecules 39 of pixels adjacent to each other in the Y direction. Further, the same effects as those of the first embodiment and the second embodiment described above can be obtained.

For example, the liquid crystal display device according to the above-described embodiment can be applied in various ways. As electronic devices to which the liquid crystal display device according to the above-described embodiments can be applied, mobile phones, portable game devices, portable information terminals, personal computers, electronic books, video cameras, digital still cameras, head mounted displays, navigation systems, Examples include sound reproducing devices (car audio, digital audio player, etc.), copying machines, facsimiles, printers, printer multifunction devices, vending machines, automatic teller machines (ATMs), personal authentication devices, optical communication devices, and the like. Each of the above embodiments can be used in any combination.

The liquid crystal driving method applicable to the present invention is not limited to the liquid crystal driving method described in the above embodiment. For example, the liquid crystal driving method described below may be used.
For example, the liquid crystal may be driven by inverting the polarity of the signal electrode (source wiring) in the active matrix (for example, described in Japanese Patent No. 2982877).
Further, in the active matrix driving of liquid crystal, dot inversion driving may be performed by alternately switching the first signal line (source wiring) and the second signal line for each horizontal period of liquid crystal driving (for example, see Japanese Patent Laid-Open No. Hei. 11-102174).
Further, in active matrix driving of liquid crystal, two source wirings per pixel are used as a data drive (source wiring), and an image signal having a different polarity for each frame is transmitted to the data drive to perform horizontal line driving. Good (for example, described in JP-A-9-134152).
In the active matrix driving of liquid crystal, two gate wirings per pixel may be used as scanning signal lines (gate wirings). In this case, for example, reverse polarity data is written to the odd-numbered scanning signal lines and the even-numbered scanning signal lines. In a certain display period, data of opposite polarity may be written in the odd-numbered column and even-numbered column of adjacent pixels, respectively, and data of opposite polarity to the previous display period may be written in the next display period (see, for example, 7-181927).
When the liquid crystal driving method described above is applied to the present invention, the number of active elements (TFTs) per pixel may be one or more in any method. The liquid crystal driving technique described above can be applied to the present invention.

While preferred embodiments of the present invention have been described and described above, it should be understood that these are exemplary of the invention and should not be considered as limiting. Additions, omissions, substitutions, and other changes can be made without departing from the scope of the invention. Accordingly, the invention is not to be seen as limited by the foregoing description, but is limited by the scope of the claims.

3 ... Touch sensing wiring 4 ... Second conductive metal oxide layer (conductive metal oxide layer)
5 ... Metal layer 6 ... First conductive metal oxide layer (conductive metal oxide layer)
8 ... Black layer 10 ... Gate wiring 11 ... First insulating layer 11F ... Filling portion 11H ... Through hole 11T ... Upper surface 12 ... Second insulating layer 12H ... Through Hole 12T ... Upper surface 13 ... Third insulating layer 13A ... Projection 14 ... Fourth insulating layer 16 ... Transparent resin layer 17 ... Common electrode 17A ... Electrode portion 17B ... Conductive connecting portion 17K ... wall 18 ... pixel opening 20 ... pixel electrode 20K ... inner wall 20S ... through hole 21 ... transparent substrate (first transparent substrate)
22 ... Transparent substrate (second transparent substrate)
24 ... Source electrode 25 ... Gate electrode 26 ... Drain electrode 27 ... Channel layer 28 ... Active element 29 ... Contact hole 30 ... Common wiring (conductive wiring)
31 ... Source wiring 33 ... Electric field line 34 ... Terminal part 39 ... Liquid crystal molecule 43H ... Third contact hole (contact hole)
51 ... Color filter 100 ... Display device substrate 110 ... Display unit 120 ... Control unit 121 ... Video signal control unit 122 ... Touch sensing control unit 123 ... System control unit 200- .... Array substrate 206 ... Liquid crystal layer 213 ... Transparent resin layer 214 ... Color filter 215 ... Transparent substrate 221 ... Counter electrode 250 ... Liquid crystal display device 250A ... Liquid crystal display device 300 ... Liquid crystal layer BM ... Black matrix BU ... Backlight unit W17A ... Width D20S ... Diameter EL ... Length H ... Contact hole L ... Light L2 ... etc. Potential line L3 ... equipotential line LH ... left contact hole (first contact hole)
RH: Right contact hole (second contact hole)
LCD1 ... Liquid crystal display device LCD2 ... Liquid crystal display device LCD3 ... Liquid crystal display device P17A ... Pitch Pa ... Upper region Pb ... Lower region Rub ... Orientation processing direction W1 ... Touch Distance W2 between sensing wiring and common electrode: Distance W3 between touch sensing wiring and source wiring W3: Height W4: Distance θ between touch sensing wiring and gate wiring: Angle (length of pixel opening) Tilt from direction Y)

Claims

A display device,
A display device substrate comprising: a first transparent substrate; and a touch sensing wiring provided on the first transparent substrate and extending in a first direction;
One or more second transparent substrates, a plurality of polygonal pixel openings on the second transparent substrate, and one or more provided in each of the plurality of pixel openings and extending in the first direction in plan view A common electrode having a plurality of electrode portions, a first insulating layer provided under the common electrode, a pixel electrode provided under the first insulating layer in each of the plurality of pixel openings, and the pixel A second insulating layer provided under the electrode; and the plurality of pixels electrically connected to the common electrode under the second insulating layer and extending in a second direction orthogonal to the first direction. A conductive wiring crossing the opening; a third insulating layer provided under the conductive wiring; and a top gate structure provided under the third insulating layer and electrically connected to the pixel electrode. An active element which is a thin film transistor, and the conductive wiring The same layer configuration is formed at the same position as the conductive wiring between the second insulating layer and the third insulating layer, and extends in the second direction in plan view to form the active element. An electrically linked gate wiring, a source wiring extending in the first direction in a plan view and electrically linked to the active element, and provided in the center in the longitudinal direction of the pattern of the electrode portion; And an array substrate comprising a contact hole for electrically connecting the common electrode and the conductive wiring,
A display functional layer sandwiched between the display device substrate and the array substrate;
An image is displayed by driving the display functional layer by applying a driving voltage between the pixel electrode and the common electrode, and a change in capacitance between the common electrode and the touch sensing wiring is performed. A control unit that detects and performs touch sensing;
Including
The display device in which the touch sensing wiring and the common electrode face each other in an oblique direction inclined with respect to the thickness direction of the display functional layer.
The display device according to claim 1, wherein the common electrode has a stripe pattern extending in a longitudinal direction parallel to the touch sensing wiring in a plan view.
The display device according to claim 1, wherein the active element includes a channel layer made of an oxide semiconductor, and the channel layer is a thin film transistor in contact with a gate insulating film.
The display device according to claim 3, wherein the oxide semiconductor is an oxide semiconductor containing two or more metal oxides of gallium, indium, zinc, tin, aluminum, germanium, antimony, bismuth, and cerium.
4. The display device according to claim 3, wherein the gate insulating film is a gate insulating film formed of a complex oxide containing cerium oxide.
The display function layer is a liquid crystal layer,
The liquid crystal of the liquid crystal layer is
Having an initial orientation parallel to the array substrate;
The display device according to claim 1, wherein the display device is driven by a fringe electric field generated by a liquid crystal driving voltage applied between the common electrode and the pixel electrode.
The display device according to claim 1, wherein the common electrode and the pixel electrode are made of a composite oxide containing at least indium oxide and tin oxide.
The display device according to claim 1, wherein the touch sensing wiring is configured by a metal layer including a copper alloy layer.
The display device according to claim 1, wherein the touch sensing wiring has a structure in which a copper alloy layer is sandwiched between conductive metal oxide layers.
The display device according to claim 1, wherein the conductive wiring has a structure in which a copper alloy layer is sandwiched between conductive metal oxide layers.
The display device according to claim 9 or 10, wherein the conductive metal oxide layer is a composite oxide layer containing two or more of indium oxide, zinc oxide, antimony oxide, and tin oxide.
The display device substrate includes a black matrix provided between the first transparent substrate and the touch sensing wiring,
The display device according to claim 1, wherein the touch sensing wiring overlaps a part of the black matrix.
The display device according to claim 1, wherein the display device substrate includes a color filter provided at a position corresponding to a plurality of pixel openings.