Patent Publication Number: US-2021173245-A1

Title: Display apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority from Japanese Patent Application No. 2018-157526 filed on Aug. 24, 2018 and International Patent Application No. PCT/JP2019/028668 filed on Jul. 22, 2019, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a display apparatus. 
     2. Description of the Related Art 
     In recent years, touch detection apparatuses commonly called touchscreen panels capable of detecting an external proximate object have been attracting attention. Such a touchscreen panel is mounted on or integrated with a display apparatus such as a liquid crystal display apparatus, which is used as a display apparatus with a touch detection apparatus. A capacitance method and an electromagnetic induction method are known as methods for detecting such an external proximate object. In the electromagnetic induction method, coils for generating magnetic fields and coils for detecting the magnetic fields are provided in the display apparatus. A pen serving as the external object is provided with a coil and a capacitive element forming a resonant circuit. The display apparatus detects the pen using electromagnetic induction between each of the coils in the display apparatus and the coil in the pen. Japanese Patent Application Laid-open Publication No. H10-49301 describes a coordinate input device using the electromagnetic induction method. 
     The capacitance method greatly differs from the electromagnetic induction method in the configuration of a detection target and detection electrodes. Therefore, if the electrodes and various types of wiring provided in the display apparatus and the drive configuration thereof are employed without modification in the electromagnetic induction method, the electromagnetic induction touch detection may be difficult to be satisfactorily performed. 
     SUMMARY 
     According to an aspect, a display apparatus includes: a substrate; a plurality of pixel electrodes provided in a display area; a plurality of switching elements coupled to the respective pixel electrodes; a plurality of first electrodes provided between semiconductors of the switching elements and the substrate in a direction orthogonal to the substrate and extending in a first direction; a plurality of signal lines coupled to the switching elements and extending in a second direction intersecting the first direction; a coupling member provided in a peripheral area outside the display area and configured to couple ends of the first electrodes to each other; and a drive circuit configured to output a first drive signal to the first electrodes or the signal lines during a first sensing period in which an electromagnetic induction method is used. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating a configuration of a display apparatus according to a first embodiment of the present disclosure; 
         FIG. 2  is an explanatory diagram for explaining electromagnetic induction touch detection; 
         FIG. 3  is a sectional view illustrating a schematic structure of the display apparatus according to the first embodiment; 
         FIG. 4  is a plan view schematically illustrating the display apparatus according to the first embodiment; 
         FIG. 5  is a circuit diagram illustrating a pixel array of the display apparatus according to the first embodiment; 
         FIG. 6  is a VI-VI′ sectional view of  FIG. 4 ; 
         FIG. 7  is a plan view illustrating an enlarged view of first electrodes according to the first embodiment; 
         FIG. 8  is a circuit diagram illustrating a coupling configuration of the first electrodes according to the first embodiment; 
         FIG. 9  is a block diagram illustrating a drive circuit that supplies various signals; 
         FIG. 10  is a circuit diagram illustrating a coupling configuration of signal lines according to the first embodiment; 
         FIG. 11  is a circuit diagram illustrating a coupling configuration of the first electrodes and the signal lines according to a second embodiment of the present disclosure; 
         FIG. 12  is a plan view illustrating an enlarged view of a coupling portion between the first electrodes and detection signal output lines according to the second embodiment; 
         FIG. 13  is a XIII-XIII′ sectional view of  FIG. 12 ; 
         FIG. 14  is a circuit diagram illustrating a coupling configuration of gate lines and the signal lines according to a third embodiment of the present disclosure; 
         FIG. 15  is a timing waveform diagram illustrating an operation example of the display apparatus according to the third embodiment; 
         FIG. 16  is a circuit diagram illustrating a coupling configuration of the gate lines and the signal lines according to a fourth embodiment of the present disclosure; 
         FIG. 17  is a plan view schematically illustrating a display apparatus according to a fifth embodiment of the present disclosure; and 
         FIG. 18  is a sectional view illustrating a schematic structure of a display apparatus according to a sixth embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following describes embodiments for carrying out the present disclosure in detail with reference to the drawings. The present disclosure is not limited to the description of the embodiments given below. Components described below include those easily conceivable by those skilled in the art or those substantially identical thereto. Moreover, the components described below can be appropriately combined. The disclosure is merely an example, and the present disclosure naturally encompasses appropriate modifications easily conceivable by those skilled in the art while maintaining the gist of the disclosure. To further clarify the description, widths, thicknesses, shapes, and other properties of various parts are schematically illustrated in the drawings as compared with actual aspects thereof, in some cases. However, they are merely examples, and interpretation of the present disclosure is not limited thereto. The same element as that illustrated in a drawing that has already been discussed is denoted by the same reference numeral through the description and the drawings, and detailed description thereof will not be repeated in some cases where appropriate. 
     In this disclosure, when an element is described as being “on” another element, the element can be directly on the other element, or there can be one or more elements between the element and the other element. 
     First Embodiment 
       FIG. 1  is a block diagram illustrating a configuration of a display apparatus according to a first embodiment of the present disclosure. A display apparatus  1  of the present embodiment incorporates a detection function to detect contact with and/or proximity to a display surface by a detection target body. As illustrated in  FIG. 1 , the display apparatus  1  includes a display panel  20 , a first detection control circuit  10 , a second detection control circuit  12 , a display control circuit  14 , a gate driver  15 , a first coupling switching circuit  16 , a second coupling switching circuit  17 , a drive circuit  18 , and a controller  200 . 
     The display panel  20  is, for example, a liquid crystal display apparatus that uses liquid crystals as display elements. The display panel  20  is a device that performs display in response to a scan signal Vscan supplied from the gate driver  15 . More specifically, the display panel  20  is a device that sequentially scans each horizontal line in response to the scan signal Vscan to perform the display. 
     The controller  200  is a circuit that supplies a control signal Vctrl to the first detection control circuit  10 , the second detection control circuit  12 , and the display control circuit  14  to control the display and the detection of the display panel  20 . The first detection control circuit  10 , the second detection control circuit  12 , and the display control circuit  14  are provided as a drive integrated circuit (IC)  19  on the display panel  20 . The drive IC  19  may, however, be provided to a wiring substrate  71  or a control circuit substrate coupled to the display panel  20 . At least one of the first detection control circuit  10 , the second detection control circuit  12 , the drive circuit  18 , and the display control circuit  14  may be provided to the display panel  20  without being incorporated in the drive IC  19 . The wiring substrate  71  is, for example, a flexible printed circuit board. 
     The display control circuit  14  supplies control signals to the gate driver  15  and the first coupling switching circuit  16  based on a video signal Vdisp supplied from the controller  200 . 
     The gate driver  15  is a circuit that sequentially selects one horizontal line as a target of display driving of the display panel  20  based on a control signal supplied from the display control circuit  14 . 
     The first coupling switching circuit  16  and the second coupling switching circuit  17  are switching circuits that change a coupling state of signal lines SGL based on a switching signal Vss from the first detection control circuit  10 . The first coupling switching circuit  16  supplies a pixel signal Vpix to each pixel Pix of the display panel  20  based on the control signal supplied from the display control circuit  14  during a display period. The display control circuit  14  supplies a display drive signal Vcomdc through the drive circuit  18  to detection electrodes  22  during the display period. 
     The display panel  20  has a function to perform self-capacitive touch detection to detect a position of a finger in contact with or in proximity to the display surface of the display panel  20 . The display panel  20  also has a function to perform electromagnetic induction touch detection to detect a touch pen  100  in contact with or in proximity to the display surface. A timing controller TC supplies control signals TSVD and TSHD for controlling timing of the electromagnetic induction touch detection by the first detection control circuit  10 , the self-capacitive touch detection by the second detection control circuit  12 , and the display by the display control circuit  14 . 
     The first detection control circuit  10  is a circuit that controls the electromagnetic induction touch detection based on the control signals TSVD and TSHD supplied from the timing controller TC included in the drive IC  19 . The first detection control circuit  10  supplies a first drive signal VTP through the drive circuit  18  to transmitting coils CTx formed by electrodes or wiring of the display panel  20  during an electromagnetic induction detection period (hereinafter, called “first sensing period”). When any one of receiving coils CRx of the display panel  20  has detected the contact or the proximity of the touch pen  100  using an electromagnetic induction method, the receiving coil CRx outputs a first detection signal Vdet 1  to the first detection control circuit  10 . In the present embodiment, the transmitting coils CTx are first electrodes  67 , and the receiving coils CRx are the signal lines SGL. 
     The second detection control circuit  12  is a circuit that controls the capacitive touch detection based on the control signals supplied from the controller  200  and the timing controller TC. The second detection control circuit  12  supplies a second drive signal VSELF through the drive circuit  18  to the detection electrodes  22  of the display panel  20  during a capacitive detection period (hereinafter, called “second sensing period”). When the display panel  20  has detected the contact or the proximity of the finger using the capacitance method, the display panel  20  outputs a second detection signal Vdet 2  to the second detection control circuit  12 . The first drive signal VTP and the second drive signal VSELF are each, for example, an alternating-current rectangular wave having a predetermined frequency (ranging, for example, roughly from several kilohertz to several hundred kilohertz). The alternating-current waveform of each of the first drive signal VTP and the second drive signal VSELF may be a sinusoidal waveform or a triangular waveform. 
     The first detection control circuit  10  includes a first detection circuit  11  that receives the first detection signals Vdet 1  from the receiving coils CRx. The first detection circuit  11  transmits the received first detection signals Vdet 1  as output signals to outside the display panel  20  (to, for example, the controller  200 ). The second detection control circuit  12  includes a second detection circuit  13  that receives the second detection signals Vdet 2  from the detection electrodes  22 . The second detection circuit  13  transmits the received second detection signals Vdet 2  as output signals to outside the display panel  20  (to, for example, the controller  200 ). The first detection circuit  11  and the second detection circuit  13 , that is, the first detection circuit  11  and the second detection circuit  13  serving as, for example, analog front-end (hereinafter, referred to as AFE) circuits include signal processing circuits for performing signal adjustment, such as filter circuits for reducing noise and amplifying circuits for amplifying signal components of the first detection signal Vdet 1  and the second detection signal Vdet 2  supplied to the detection circuits  11  and  13 , respectively. The first detection circuit  11  and the second detection circuit  13  may include no signal processing circuits, and may supply the first detection signal Vdet 1  and the second detection signal Vdet 2  as they are as output signals to the controller  200 , and the controller  200  may include the signal processing circuits such as the filter circuits and the amplifying circuits. 
     The first detection control circuit  10  and the second detection control circuit  12  may include, for example, analog-to-digital (A/D) conversion circuits, signal processing circuits, and coordinate extraction circuits for performing signal processing of the first detection signal Vdet 1  and the second detection signal Vdet 2 , respectively. Alternatively, the controller  200  may include, for example, the A/D conversion circuits, the signal processing circuits, and the coordinate extraction circuits. 
     Each of the A/D conversion circuits samples an analog signal output from the display panel  20  and convert it into a digital signal at a time synchronized with the first drive signal VTP or the second drive signal VSELF. 
     Each of the signal processing circuits is a logic circuit that detects whether the display panel  20  is touched, based on the output signal of the A/D conversion circuit. The signal processing circuit performs processing of extracting a signal of difference (absolute value |ΔV|) in the detection signals caused by the finger. The signal processing circuit compares the absolute value |ΔV| with a predetermined threshold voltage, and determines that the detection target body is in a non-present state if the absolute value |ΔV| is lower than the threshold voltage. If, instead, the absolute value |ΔV| is equal to or higher than the threshold voltage, the signal processing circuit determines that the detection target body is in a present state. 
     Each of the coordinate extraction circuits is a logic circuit that obtains coordinates of the detection target body when the detection target body is detected by the signal processing circuit. The coordinate extraction circuit outputs the coordinates of the detection target body as output signals. The coordinate extraction circuit outputs the output signals to outside the display panel  20  (to, for example, the controller  200 ). 
     The following describes the touch detection using the electromagnetic induction method by the display panel  20  of the present embodiment with reference to  FIG. 2 .  FIG. 2  is an explanatory diagram for explaining the electromagnetic induction touch detection. 
     As illustrated in  FIG. 2 , in the electromagnetic induction method, the contact or the proximity of the touch pen  100  is detected. A resonant circuit  101  is provided in the touch pen  100 . The resonant circuit  101  is configured by coupling a coil  102  to a capacitive element  103  in parallel. 
     In the electromagnetic induction method, the transmitting coils CTx and the receiving coils CRx are provided so as to overlap each other. Each of the transmitting coils CTx has a longitudinal direction along a first direction Dx. Each of the receiving coils CRx has a longitudinal direction along a second direction Dy. Each receiving coil CRx is provided so as to intersect the transmitting coils CTx in a plan view. The transmitting coils CTx are coupled to the drive circuit  18 , and the receiving coils CRx are coupled to the first detection circuit  11  (refer to  FIG. 1 ). 
     As illustrated in  FIG. 2 , during a magnetic field generation period, the first detection control circuit  10  applies an alternating-current rectangular wave having a predetermined frequency (ranging, for example, roughly from several kilohertz to several hundred kilohertz) through the drive circuit  18  to the transmitting coils CTx. As a result, a current flows in the transmitting coils CTx, and the transmitting coils CTx generate a magnetic field M 1  corresponding to the change in current. When the touch pen  100  is in contact with or in proximity to the display surface, an electromotive force is generated in the coil  102  by mutual induction between the transmitting coils CTx and the coil  102 , whereby the capacitive element  103  is charged. 
     Then, during a magnetic field detection period, the coil  102  of the touch pen  100  generates a magnetic field M 2  that varies with a resonant frequency of the resonant circuit  101 . The magnetic field M 2  passes through the receiving coils CRx, and as a result, an electromotive force is generated in the receiving coils CRx by mutual induction between the receiving coils CRx and the coil  102 . A current corresponding to the electromotive force of the receiving coils CRx flows in the first detection circuit  11 . The touch pen  100  is detected by scanning the transmitting coils CTx and the receiving coils CRx. 
       FIG. 3  is a sectional view illustrating a schematic structure of the display apparatus according to the first embodiment.  FIG. 4  is a plan view schematically illustrating the display apparatus according to the first embodiment. As illustrated in  FIG. 3 , the display apparatus  1  includes an array substrate  2 , a counter substrate  3 , a liquid crystal layer  6 , a polarizing plate  25 , and a polarizing plate  35 . The counter substrate  3  is disposed so as to be opposed to a surface of the array substrate  2  in the direction orthogonal thereto. The liquid crystal layer  6  is provided between the array substrate  2  and the counter substrate  3 . 
     The array substrate  2  includes a first substrate  21 , the detection electrodes  22 , and pixel electrodes  24 . The array substrate  2  is a drive circuit substrate for driving each of the pixels Pix, and is also called a back plane. The first substrate  21  is provided with circuits such as a gate scanner included in the gate driver  15 , switching elements Tr such as thin-film transistors (TFTs), and various types of wiring such as gate lines GCL and the signal lines SGL (refer to  FIG. 5 ). The pixel electrodes  24  are arranged in a matrix having a row-column configuration above one surface of the first substrate  21 . 
     The detection electrodes  22  are provided between the first substrate  21  and the pixel electrodes  24 . The pixel electrodes  24  are isolated from the detection electrodes  22  with an insulating layer  27  interposed therebetween. The polarizing plate  25  is provided to the other surface of the first substrate  21  with an adhesive layer  26  interposed therebetween. In the present embodiment, the case has been described where the pixel electrodes  24  are provided on the upper sides of the detection electrodes  22 . However, the detection electrodes  22  may be provided on the upper sides of the pixel electrodes  24 . In other words, the pixel electrodes  24  may be disposed between the first substrate  21  and the detection electrode  22 . 
     The first substrate  21  is provided with the drive IC  19  and the wiring substrate  71 . The drive IC  19  has all or some of the functions of the first detection control circuit  10 , the second detection control circuit  12 , and the display control circuit  14  illustrated in  FIG. 1 . The drive IC  19  may include two or more IC chips, and one or some of the IC chips may be disposed on the wiring substrate  71 . 
     As illustrated in  FIG. 3 , the counter substrate  3  includes a second substrate  31  and a color filter  32 . The color filter  32  is provided to a surface of the second substrate  31  opposed to the first substrate  21 . The color filter  32  is opposed to the liquid crystal layer  6  in the direction orthogonal to the first substrate  21 . The polarizing plate  35  is provided on the second substrate  31  with an adhesive layer  36  interposed therebetween. The first substrate  21  and the second substrate  31  are light-transmitting glass substrates capable of transmitting visible light. Alternatively, the first substrate  21  and the second substrate  31  may be light-transmitting resin substrates or resin films made of a resin such as polyimide. The color filter  32  may be provided to the first substrate  21 . 
     The first substrate  21  is disposed opposed to the second substrate  31  with a predetermined gap provided therebetween by a seal portion  66 . The liquid crystal layer  6  is provided in a space surrounded by the first substrate  21 , the second substrate  31 , and the seal portion  66 . The liquid crystal layer  6  modulates light passing therethrough according to a state of an electric field, and is made using, for example, liquid crystals in a horizontal electric field mode, such as in-plane switching (IPS) including fringe field switching (FFS). The liquid crystal layer  6  is provided as a display layer for displaying an image. An orientation film is provided between the liquid crystal layer  6  and the array substrate  2  and between the liquid crystal layer  6  and the counter substrate  3  illustrated in  FIG. 3 . 
     In this specification, in a direction orthogonal to the surface of the first substrate  21 , the term “upper side” refers to a direction from the first substrate  21  toward the second substrate  31 , and the term “lower side” refers to a direction from the second substrate  31  toward the first substrate  21 . The term “plan view” refers to a case of viewing from a direction orthogonal to the surface of the first substrate  21 . 
     The first direction Dx and the second direction Dy are directions parallel to the surface of the first substrate  21 . The first direction Dx is orthogonal to the second direction Dy. The first direction Dx may, however, non-orthogonally intersect the second direction Dy. A third direction Dz is a direction orthogonal to the surface of the first substrate  21 . The third direction Dz is orthogonal to the first direction Dx and the second direction Dy. 
     As illustrated in  FIG. 4 , an area corresponding to a display area AA of the display panel  20  and an area corresponding to a peripheral area GA provided outside the display area AA are formed on the first substrate  21 . The display area AA is an area overlapping the pixels Pix. The display area AA is also an area including detection elements such as the detection electrodes  22  and the first electrodes  67  (refer to  FIG. 6 ). In other words, the display area AA is an area that can detect whether the display surface is touched by, for example, the finger and/or the touch pen  100 . 
     The detection electrodes  22  are arranged in a matrix having a row-column configuration in the display area AA. Each of the detection electrodes  22  is rectangular or square in the plan view. The detection electrode  22  is made of a light-transmitting electrically conductive material such as indium tin oxide (ITO). The detection electrode  22  may have another shape such as a polygonal shape. 
     Detection electrode lines  51  are electrically coupled to the respective detection electrodes  22 . The plurality of detection electrode lines  51  extend in the second direction Dy and are arranged in the first direction Dx. In the present embodiment, the detection electrode lines  51  are provided in a layer different from that of the detection electrodes  22 , and are provided in an area overlapping the detection electrodes  22  in the plan view. Each of the detection electrode lines  51  is coupled to the second detection circuit  13  included in the drive IC  19 . 
       FIG. 5  is a circuit diagram illustrating a pixel array of the display apparatus according to the first embodiment. As illustrated in  FIG. 5 , the display panel  20  includes the pixels Pix arranged in a matrix having a row-column configuration. Each of the pixels Pix includes one of the switching elements Tr and a liquid crystal element  6   a . The switching element Tr is formed of a thin-film transistor, and in the present example, formed of an n-channel metal oxide semiconductor (MOS) TFT. The insulating layer  27  is provided between the pixel electrodes  24  and the detection electrodes  22  (common electrodes), and these components generate retention capacitance  6   b  illustrated in  FIG. 5 . 
     The gate driver  15  illustrated in  FIG. 1  sequentially selects the gate lines GCL. The gate driver  15  applies the scan signal Vscan to the gate of each of the switching elements Tr of the pixels Pix through the selected one of the gate lines GCL. This operation sequentially selects one row (one horizontal line) of the pixels Pix as the target of display driving. A source driver included in the display control circuit  14  supplies the pixel signal Vpix to each of the pixels Pix included in the selected one horizontal line through the signal lines SGL. These pixels Pix perform display of each horizontal line in response to the supplied pixel signals Vpix. In  FIG. 4 , the gate driver  15  is disposed in each of two areas of the peripheral area GA opposed to each other with the display area AA interposed therebetween. The gate driver  15  may, however, be disposed in either of the two areas. 
     In the color filter  32  illustrated in  FIG. 3 , for example, a color area  32 R, a color area  32 G, and a color area  32 B of the color filter  32  colored in three colors of red (R), green (G), and blue (B) are periodically arranged. The color area  32 R, the color area  32 G, and the color area  32 B of the three colors of R, G, and B are associated with each pixel Pix illustrated in  FIG. 5 . The color areas associated with each pixel Pix only need to be different colors, and may be a combination of other colors. The color areas associated with each pixel Pix are not limited to a combination of three colors, and may be a combination of four or more colors. 
     The detection electrodes  22  illustrated in  FIGS. 3 and 4  serve as common electrodes that apply a common potential to the pixels Pix of the display panel  20 , and also serve as drive electrodes and detection electrodes when the touch detection using the self-capacitance method is performed. During the display period, the display control circuit  14  supplies the display drive signal Vcomdc through the drive circuit  18  to the detection electrodes  22 . 
     As an example of an operation method of the display apparatus  1 , the display apparatus  1  performs the electromagnetic induction touch detection (first sensing period), the self-capacitive touch detection (second sensing period), and the display operation (display period) in a time-division manner. The touch detection operations and the display operation may be divided in any way. 
       FIG. 6  is a VI-VI′ sectional view of  FIG. 4 .  FIG. 7  is a plan view illustrating an enlarged view of the first electrodes according to the first embodiment.  FIG. 6  also illustrates a sectional configuration of the switching element Tr provided in the pixels Pix. 
     As illustrated in  FIG. 6 , the switching element Tr includes a semiconductor  61 , a source electrode  62 , a drain electrode  63 , and a gate electrode  64 . The semiconductor  61  is provided on the first substrate  21  with a first insulating layer  91  interposed therebetween. The first insulating layer  91 , a second insulating layer  92 , a third insulating layer  93 , and the insulating layer  27  are made using an inorganic insulating material such as a silicon oxide (SiO) film, a silicon nitride (SiN) film, or a silicon oxide nitride (SiON) film. Each of the inorganic insulating layers is not limited to a single layer, and may be a multi-layered film. 
     The second insulating layer  92  is provided on the first insulating layer  91  so as to cover the semiconductor  61 . The gate electrode  64  is provided on the second insulating layer  92 . The gate electrode  64  is a portion of the gate line GCL overlapping the semiconductor  61 . The third insulating layer  93  is provided on the second insulating layer  92  so as to cover the gate electrode  64 . A channel area is formed at a portion of the semiconductor  61  overlapping the gate electrode  64 . 
     In the example illustrated in  FIG. 6 , the switching element Tr has what is called a top-gate structure. However, the switching element Tr may have a bottom-gate structure in which the gate electrode  64  is provided below the semiconductor  61 . The switching element Tr may have a dual-gate structure in which the gate electrodes  64  are provided so as to interpose the semiconductor  61  therebetween in a direction orthogonal to the first substrate  21 . 
     The semiconductor  61  is formed of, for example, amorphous silicon, a microcrystalline oxide semiconductor, an amorphous oxide semiconductor, polycrystalline silicon, low-temperature polycrystalline silicon (hereinafter, called LTPS), or gallium nitride (GaN). 
     The source electrode  62  and the drain electrode  63  are provided on the third insulating layer  93 . In the present embodiment, the source electrode  62  is electrically coupled to the semiconductor  61  through a contact hole H 2 . The drain electrode  63  is electrically coupled to the semiconductor  61  through a contact hole H 3 . The source electrode  62  is a portion of each of the signal lines SGL overlapping the semiconductor  61 . 
     A fourth insulating layer  94  and a fifth insulating layer  95  are provided on the third insulating layer  93  so as to cover the source electrode  62  and the drain electrode  63 . The fourth insulating layer  94  and the fifth insulating layer  95  are planarizing layers that planarize asperities formed by the switching elements Tr and the various types of wiring. 
     A relay electrode  65  and the detection electrode lines  51  are provided on the fourth insulating layer  94 . The relay electrode  65  is electrically coupled to the drain electrode  63  through a contact hole H 4 . The detection electrode lines  51  are provided on the upper sides of the signal lines SGL. The detection electrodes  22  are provided on the fifth insulating layer  95 . The detection electrode  22  is electrically coupled to the detection electrode line  51  through a contact hole H 1 . 
     Each of the pixel electrodes  24  electrically coupled to the relay electrode  65  through a contact hole H 5  provided in the insulating layer  27  and the fifth insulating layer  95 . The contact hole H 5  is formed in a position overlapping an opening  22   a  of the detection electrode  22 . The above-described configuration couples the pixel electrodes  24  to the respective switching elements Tr. 
     Each of the first electrodes  67  is provided between the first substrate  21  and the semiconductor  61  in the direction orthogonal to the first substrate  21 . In other words, the semiconductor  61  is provided between the first electrode  67  and the gate electrode  64  in the direction orthogonal to the first substrate  21 . The first electrode  67  is made of a material having light transmittance lower than that of the first substrate  21 , and is used as a light-shielding layer. For example, a metal material is used as the first electrode  67 . 
     As illustrated in  FIG. 7 , in the signal line SGL, a first portion SGLs inclining along a direction D 1  and a second portion SGLt inclining along a direction D 2  are alternately coupled along the second direction Dy. The signal line SGL extends in the second direction Dy as a whole. The gate line GCL extends in the first direction Dx so as to intersect the signal lines SGL. For ease of viewing,  FIG. 7  does not illustrate the pixel electrode  24  of each of the pixels Pix. 
     The direction D 1  is a direction inclining by an angle θ 1  with respect to the second direction Dy. The direction D 2  is a direction inclined to a side opposite to a side to which the direction D 1  is inclined with respect to the second direction Dy. The angle formed between the direction D 2  and the second direction Dy is an angle θ 2 . The angle θ1 equals the angle θ 2 . The angle θ 1  may, however, differ from the angle θ 2 . 
     The first electrode  67  extends along the gate line GCL in the first direction Dx, and is provided below the gate line GCL and the switching elements Tr. The first electrode  67  is continuously provided across the pixels Pix and the switching elements Tr arranged in the first direction Dx. The first electrode  67  serves as the light-shielding layer, and only needs to be provided at least below a part where the semiconductor  61  intersects the gate line GCL. This configuration allows the first electrode  67  to reduce a light leakage current of the switching elements Tr. 
       FIG. 8  is a circuit diagram illustrating a coupling configuration of the first electrodes according to the first embodiment.  FIG. 9  is a block diagram illustrating the drive circuit that supplies various signals.  FIG. 8  illustrates the coupling configuration of the first electrodes during the first sensing period. 
     As illustrated in  FIG. 8 , a plurality of first electrodes  67 - 1 ,  67 - 2 , . . . ,  67 - 10  are arranged in the second direction Dy. In the following description, the first electrodes  67 - 1 ,  67 - 2 , . . . ,  67 - 10  will each be referred to as the first electrode  67  when they need not be distinguished from one another. In the following description, a first end of the first electrode  67  will be referred to as the left end, and a second end thereof will be referred to as the right end, with reference to  FIG. 8 . 
     A first drive signal supply line  52  and a second drive signal supply line  54  are provided on the left end sides of the first electrodes  67 , and first drive signal supply line  53  and second drive signal supply line  55  are provided on the right end sides of the first electrodes  67 . The first drive signal supply lines  52 ,  53  and the second drive signal supply lines  54 ,  55  are wiring for supplying the first drive signal VTP to the first electrodes  67 . 
     A switch SW 11  is provided between the left end of each of the first electrodes  67  and the first drive signal supply line  52 . A switch SW 12  is provided between the left end of each of the first electrodes  67  and the second drive signal supply line  54 . The switch SW 11  and the switch SW 12  are coupled in parallel to the left end of the first electrode  67 . 
     A switch SW 13  is provided between the right end of each of the first electrodes  67  and the first drive signal supply line  53 . A switch SW 14  is provided between the right end of each of the first electrodes  67  and the second drive signal supply line  55 . The switch SW 13  and the switch SW 14  are coupled in parallel to the right end of the first electrode  67 . The first drive signal supply lines  52 ,  53 , the second drive signal supply lines  54 ,  55 , and the switches SW 11  to SW 14  are provided in the peripheral area GA. The first drive signal supply lines  52 ,  53 , the second drive signal supply lines  54 ,  55 , and the switches SW 11  to SW 14  are coupling members that couple the ends of the first electrodes  67  to one another. 
     As illustrated in  FIG. 9 , the drive circuit  18  supplies the various signals through the detection electrode lines  51 , the first drive signal supply lines  52 ,  53 , and the second drive signal supply lines  54 ,  55  to the detection electrodes  22  and the first electrodes  67 . The drive circuit  18  includes a display drive signal supply circuit  18 A, a second drive signal supply circuit  18 B, a first voltage supply circuit  18 C, and a second voltage supply circuit  18 D. The display drive signal supply circuit  18 A, the second drive signal supply circuit  18 B, the first voltage supply circuit  18 C, and the second voltage supply circuit  18 D are provided in the drive IC  19  (refer to  FIG. 1 ). At least one of the display drive signal supply circuit  18 A, the second drive signal supply circuit  18 B, the first voltage supply circuit  18 C, and the second voltage supply circuit  18 D may be provided as a circuit on the display panel  20 . 
     The display drive signal supply circuit  18 A supplies the display drive signal Vcomdc through the detection electrode lines  51  to the detection electrodes  22 . The second drive signal supply circuit  18 B supplies the second drive signal VSELF for detection through the detection electrode lines  51  to the detection electrodes  22 . The first voltage supply circuit  18 C supplies a first voltage VTPH of a direct current having a first potential through the first drive signal supply lines  52 ,  53  to the first electrodes  67 . The second voltage supply circuit  18 D supplies a second voltage VTPL through the second drive signal supply lines  54 ,  55  to the first electrodes  67 . The second voltage VTPL is a direct-current voltage signal having a second potential lower than the first potential. 
     As illustrated in  FIG. 8 , during the first sensing period, in response to a control signal from the first detection control circuit  10 , the switches SW 11 , SW 12 , SW 13 , and SW 14  operate to select the first electrodes  67  that form the transmitting coil CTx. Specifically, the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4  and the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8  are selected as first electrode blocks BKE 1  and BKE 2 . The other first electrodes  67  serve as a non-selected electrode block. An area between the first electrode  67 - 4  and the first electrode  67 - 6  serves as a detection area Aem for detecting the detection target body. 
     On the left sides of the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4 , the switches SW 11  are turned off, and the switches SW 12  are turned on. As a result, the left ends of the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4  are electrically coupled to the second drive signal supply line  54 . On the right sides of the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4 , the switches SW 13  are turned on, and the switches SW 14  are turned off. As a result, the right ends of the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4  are electrically coupled to the first drive signal supply line  53 . 
     On the left sides of the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8 , the switches SW 11  are turned on, and the switches SW 12  are turned off. As a result, the left ends of the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8  are electrically coupled to the first drive signal supply line  52 . On the right sides of the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8 , the switches SW 13  are turned off, and the switches SW 14  are turned on. As a result, the right ends of the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8  are electrically coupled to the second drive signal supply line  55 . 
     As a result, during the first sensing period, the second voltage supply circuit  18 D is coupled to the left end sides of the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4 , and the first voltage supply circuit  18 C is coupled to the right end sides thereof. In addition, the first voltage supply circuit  18 C is coupled to the left end sides of the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8 , and the second voltage supply circuit  18 D is coupled to the right end sides thereof. 
     The second voltage supply circuit  18 D supplies the second voltage VTPL through the second drive signal supply line  54  to the left ends of the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4 . The first voltage supply circuit  18 C supplies the first voltage VTPH through the first drive signal supply line  53  to the right ends of the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4 . As a result, potential differences are generated between the left ends and the right ends of the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4  to cause currents I 1  to flow in a direction from the right ends toward the left ends thereof. 
     The first voltage supply circuit  18 C supplies the first voltage VTPH through the first drive signal supply line  52  to the left ends of the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8 . The second voltage supply circuit  18 D supplies the second voltage VTPL through the second drive signal supply line  55  to the right ends of the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8 . As a result, potential differences are generated between the left ends and the right ends of the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8  to cause currents I 2  to flow in a direction from the left ends toward the right ends thereof. 
     The first detection control circuit  10  switches the operations of the switches SW 11 , SW 12 , SW 13 , and SW 14  to change the first voltage VTPH and the second voltage VTPL to be supplied to both ends of the first electrodes  67  at a predetermined frequency. This causes the drive circuit  18  to supply the first drive signal VTP serving as an alternating-current voltage signal to the first electrodes  67  during the first sensing period. 
     The currents I 1  and I 2  flowing through the first electrodes  67  generate a magnetic field to cause the electromagnetic induction. The currents I 1  and the currents I 2  flow in directions opposite to each other. As a result, the magnetic field generated by the currents I 1  overlaps the magnetic field generated by the currents I 2  in the detection area Aem. This overlap can increase the strength of the magnetic field passing through the detection area Aem. The magnetic field generated by the currents I 1  and the currents I 2  corresponds to the magnetic field M 1  generated during the magnetic field generation period of the electromagnetic induction method illustrated in  FIG. 2 . The first electrodes  67 - 2 ,  67 - 3 , and  67 - 4  included in the first electrode block BKE 1  and the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8  included in the first electrode block BKE 2  correspond to the transmitting coil CTx. 
     In  FIG. 8 , the switches SW 11  and SW 12  and the switches SW 13  and SW 14  for the first electrodes  67  (the first electrodes  67 - 1 ,  67 - 5 ,  67 - 9 ,  67 - 10 ) in the non-selected electrode block are turned off. This operation brings the first electrodes  67  in the non-selected electrode block into a floating state. 
     The first detection control circuit  10  sequentially selects the first electrode  67 - 1  to the first electrode  67 - 10 . As a result, the touch detection is performed over the entire display area AA using the electromagnetic induction method. The first electrodes  67  may also be provided in the peripheral area GA. This configuration can also generate magnetic fields in the peripheral portion of the display area AA. 
     In  FIG. 8 , the transmitting coil CTx is formed by six of the first electrodes  67 . The transmitting coil CTx is, however, not limited to this configuration, and may be formed by one or two of the first electrodes  67  disposed on one side of the detection area Aem and one or two of the first electrodes  67  disposed on the other side of the detection area Aem. The transmitting coil CTx may be formed by four or more of the first electrodes  67  disposed on one side of the detection area Aem and four or more of the first electrodes  67  disposed on the other side of the detection area Aem. The numbers of the first electrodes  67  for forming the coil need not be the same between the one side and the other side of the detection area Aem. A configuration can be employed in which the number of the first electrodes  67  on one side differs from that of the first electrodes  67  on the other side. The number of the first electrodes  67  disposed between first electrodes  67  through which the currents flow in different directions, that is, between the first electrodes  67  through which the currents I 1  flow and the first electrodes  67  through which the currents I 2  flow is not limited to one, and may be zero or an integer of two or greater. 
     As described above, the display apparatus  1  includes the first drive signal supply lines  52 ,  53  that supply the first voltage VTPH to the first electrodes  67  and the second drive signal supply lines  54 ,  55  that supply the second voltage VTPL lower than the first voltage VTPH to the first electrodes  67 . During the first sensing period, the first drive signal supply line  52  is coupled to the first end side of at least one of the first electrodes  67 , and the second drive signal supply line  55  is coupled to the second end side thereof. In addition, the second drive signal supply line  54  is coupled to the first end sides of the first electrodes  67  other than the at least one of the first electrodes  67 , and the first drive signal supply line  53  is coupled to the second end sides thereof. 
     During the display period, the display drive signal supply circuit  18 A supplies the display drive signal Vcomdc through the detection electrode lines  51  to the detection electrodes  22 . During the display period, all the switches SW 11 , SW 12 , SW 13 , and SW 14  are turned off in response to the control signal from the first detection control circuit  10 . As a result, all the first electrodes  67  are uncoupled from the first drive signal supply lines  52 ,  53  and the second drive signal supply lines  54 ,  55  to be brought into the floating state. 
     During the self-capacitive detection period, the second drive signal supply circuit  18 B supplies the second drive signal VSELF for detection through the detection electrode lines  51  to the detection electrodes  22 . The detection electrodes  22  output a signal (second detection signal Vdet 2 ) corresponding to a change in the self-capacitance caused by the contact or the proximity of the detection target body to the second detection circuit  13 . In this case, the first detection control circuit  10  turns on all the switches SW 11  and SW 13  and turns off all the switches SW 12  and SW 14 . The second drive signal supply circuit  18 B supplies a guard drive signal through the first drive signal supply lines  52 ,  53  to all the first electrodes  67 . The guard drive signal is a voltage signal synchronized with the second drive signal VSELF and having the same amplitude as the second drive signal VSELF. This operation can restrain capacitance coupling between the detection electrodes  22  and the first electrodes  67 . 
     The coupling configuration illustrated in  FIG. 8  is merely an example and can be modified as appropriate. For example, during the first sensing period, the first voltage supply circuit  18 C and the second voltage supply circuit  18 D may respectively supply the first voltage VTPH and the second voltage VTPL only to the left ends of the first electrodes  67 . The second voltage supply circuit  18 D supplies the second voltage VTPL through the second drive signal supply line  54  to the left ends of the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4 . The first voltage supply circuit  18 C supplies the first voltage VTPH through the first drive signal supply line  52  to the left ends of the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8 . 
     The right ends of the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4  are electrically coupled to the right ends of the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8  through at least one of the first drive signal supply line  53  and the second drive signal supply line  55 . Also in this case, the first electrodes  67 - 2 ,  67 - 3 , and  67 - 4  and the first electrodes  67 - 6 ,  67 - 7 , and  67 - 8  are formed into the transmitting coil CTx. 
       FIG. 10  is a circuit diagram illustrating a coupling configuration of the signal lines according to the first embodiment.  FIG. 10  illustrates four signal lines SGL 1 , SGL 2 , SGL 3 , and SGL 4  among the signal lines SGL. In the following description, the signal lines SGL 1 , SGL 2 , SGL 3 , and SGL 4  will each be referred to as the signal line SGL when they need not be distinguished from one another.  FIG. 10  illustrates each of the first electrodes  67  with a long dashed double-short dashed line. 
     As illustrated in  FIG. 10 , the signal lines SGL are provided so as to intersect the first electrodes  67  in the plan view. The first coupling switching circuit  16  is provided on one side of each of the signal lines SGL 1 , SGL 2 , SGL 3 , and SGL 4 , and the second coupling switching circuit  17  is provided on the other side thereof. The first coupling switching circuit  16  is a switching circuit including switches SW 21 , SW 22 , and SW 24 . The second coupling switching circuit  17  is a switching circuit including switches SW 23  and signal line coupling lines  56 . In the following description, a first end of the signal line SGL will be referred to as a lower end, and a second end thereof will be referred to as an upper end, with reference to  FIG. 10 . 
     In the first coupling switching circuit  16 , the switches SW 21  switch between coupling and uncoupling the signal lines SGL 1  and SGL 2  and the first detection circuit  11 . The switches SW 22  switch between coupling and uncoupling the signal lines SGL and the display control circuit  14 . The switches SW 24  switch between coupling and uncoupling the signal lines SGL 3  and SGL 4  and a reference potential (for example, a ground potential GND). 
     In the second coupling switching circuit  17 , the switches SW 23  and the signal line coupling line  56  switch between coupling and uncoupling the upper ends of a pair of the signal lines SGL 1  and SGL 3 , and the switches SW 23  and the signal line coupling line  56  switch between coupling and uncoupling the upper ends of a pair of the signal lines SGL 2  and SGL 4 . 
     During the first sensing period, the switches SW 23  are turned on in response to the control signal from the first detection control circuit  10 . As a result, the upper ends of the pair of the signal lines SGL 1  and SGL 3  are coupled to each other through the signal line coupling line  56 . In the same manner, the upper ends of the pair of the signal lines SGL 2  and SGL 4  are coupled to each other through the signal line coupling line  56 . On the lower end sides of the signal lines SGL, the switches SW 22  are turned off, and the switches SW 21  and SW 24  are turned on. As a result, the lower ends of the signal line SGL 1  and the signal line SGL 2  are each coupled to the first detection circuit  11 . In addition, the lower ends of the signal line SGL 3  and the signal line SGL 4  are coupled to the reference potential (for example, the ground potential GND). 
     As described above, the first coupling switching circuit  16  couples a first end side of at least one of the signal lines SGL to the first detection circuit  11  during the first sensing period. The second coupling switching circuit  17  couples the second end sides of a plurality of the signal lines SGL to each other during the first sensing period. 
     With the above-described configuration, the signal lines SGL 1  and SGL 3  are coupled to form a loop as the receiving coil CRx. In addition, the signal lines SGL 2  and SGL 4  are coupled to form a loop as the receiving coil CRx. The receiving coils CRx are provided so as to overlap the detection area Aem formed by the first electrodes  67 . The receiving coils CRx may be formed by signal line blocks each including a plurality of the signal lines SGL, in the same manner as the transmitting coil CTx illustrated in  FIG. 8 . 
     When the magnetic field M 2  from the touch pen  100  (refer to  FIG. 2 ) passes through an area surrounded by the pair of the signal lines SGL 1  and SGL 3  and the signal line coupling line  56  or an area surrounded by the pair of the signal lines SGL 2  and SGL 4  and the signal line coupling line  56 , an electromotive force corresponding to a variation in the magnetic field M 2  is generated in each of the receiving coils CRx. The first detection signal Vdet 1  corresponding to this electromotive force is supplied to the first detection circuit  11 . In this manner, during the first sensing period, the first electrodes  67  are supplied with the first drive signal VTP from the drive circuit  18  to generate a magnetic field, and an electromotive force due to the magnetic field is generated in the signal lines SGL. Thus, the display apparatus  1  can detect the touch pen  100 . 
     In the present embodiment, the adjacent receiving coils CRx are arranged so as to partially overlap each other. Specifically, the area surrounded by the pair of the signal lines SGL 1  and SGL 3  and the signal line coupling line  56  forming one receiving coil CRx includes the signal line SGL 2  of the other of the receiving coil CRx. In addition, the area surrounded by the pair of the signal lines SGL 2  and SGL 4  and the signal line coupling line  56  forming the other receiving coil CRx includes the signal line SGL 3  of the one receiving coil CRx. This configuration can restrain generation of an area in the display area AA where detection sensitivity of magnetic fields is reduced, or an insensitive area in the display area AA where magnetic fields cannot be detected. 
     During the display period, the switches SW 23  are turned off in response to the control signal from the first detection control circuit  10 . As a result, the upper ends of the signal lines SGL 1 , SGL 2 , SGL 3 , and SGL 4  are uncoupled from one another. The switches SW 21  and SW 24  are turned off, and the switches SW 22  are turned on. As a result, the lower ends of the signal lines SGL 1 , SGL 2 , SGL 3 , and SGL 4  are uncoupled from the first detection circuit  11  and the reference potential (for example, the ground potential GND). The pixel signals Vpix are supplied through the switches SW 22  to the signal lines SGL. 
     During the second sensing period, the second detection control circuit  12  may supply the guard drive signal to the signal lines SGL. Alternatively, the second detection control circuit  12  may bring the signal lines SGL into the floating state. 
     The first electrodes  67  forming the transmitting coils CTx are a metal material having a higher electrical conductivity than the detection electrodes  22 , and have a significantly lower resistance than the detection electrodes  22 . As a result, it is possible, by using the first electrodes  67  as the drive electrodes (transmitting coils CTx), to hamper the first drive signal VTP as the alternating-current rectangular wave from being rounded. As a result, in the present embodiment, responsiveness to the first drive signal VTP is increased and the detection sensitivity is improved in the electromagnetic induction touch detection. 
     Second Embodiment 
       FIG. 11  is a circuit diagram illustrating a coupling configuration of the first electrodes and the signal lines according to a second embodiment of the present disclosure.  FIG. 12  is a plan view illustrating an enlarged view of a coupling portion between the first electrodes and detection signal output lines according to the second embodiment.  FIG. 13  is a XIII-XIII′ sectional view of  FIG. 12 .  FIG. 13  also illustrates a multi-layered configuration of the switching element Tr provided in the pixel Pix. In the following description, the components described in the above-described embodiment will be denoted by the same reference numerals, and will not be described. 
     In the present embodiment, during the first sensing period, the signal lines SGL are supplied with the first drive signal VTP from the drive circuit  18  to generate a magnetic field, and an electromotive force due to the magnetic field is generated in the first electrodes  67 . That is, the signal lines SGL form the transmitting coils CTx, and the first electrodes  67  form the receiving coils CRx. 
     As illustrated in  FIG. 11 , the signal lines SGL extend in the second direction Dy and are arranged in the first direction Dx. The signal lines SGL including the signal lines SGL 1 , SGL 2 , and SGL 3  serve as a signal line block BKS 1 . The signal lines SGL including signal lines SGL 4 , SGL 5 , and SGL 6  serve as a signal line block BKS 2 . The lower end sides of the signal line blocks BKS 1  and BKS 2  are provided with first drive signal supply line  52 A and second drive signal supply line  54 A. The lower end sides of the signal line block BKS 1  and the signal line block BKS 2  are provided with a first coupling switching circuit  16 A, and the upper end sides thereof are provided with a second coupling switching circuit  17 A. 
     The first coupling switching circuit  16 A is a switching circuit including switches SW 22 , SW 25 , and SW 26 . The switches SW 22  switch between coupling and uncoupling the signal lines SGL and the display control circuit  14 . The switches SW 25  switch between coupling and uncoupling the lower ends of the signal lines SGL and the first drive signal supply line  52 A. The switches SW 26  switch between coupling and uncoupling the lower ends of the signal lines SGL and the second drive signal supply line  54 A. 
     As in the first embodiment, the second coupling switching circuit  17 A switches between coupling and uncoupling the upper ends of a pair of the signal line block BKS 1  and the signal line block BKS 2 . The switches such as the switches SW 22 , SW 23 , SW 25 , and SW 26  are only partially illustrated, but are provided for each of the signal lines SGL. 
     During the first sensing period, the switches SW 23  are turned on to couple the upper ends of the signal line block BKS 1  and the signal line block BKS 2  together through the signal line coupling line  56 . On the lower end side of the signal line block BKS 1 , the switches SW 26  are turned on, and the switches SW 25  are turned off. On the lower end side of the signal line block BKS 2 , the switches SW 26  are turned off, and the switches SW 25  are turned on. 
     The first voltage supply circuit  18 C (refer to  FIG. 9 ) supplies the first voltage VTPH through the first drive signal supply line  52 A to the lower end of the signal line block BKS 2 . The second voltage supply circuit  18 D (refer to  FIG. 9 ) supplies the second voltage VTPL through the second drive signal supply line  54 A to the lower end of the signal line block BKS 1 . As a result, a potential difference is generated between the lower end of the signal line block BKS 1  and the lower end of the signal line block BKS 2  in paths formed by the signal line block BKS 1 , the signal line coupling line  56 , and the signal line block BKS 2 . The potential difference causes the currents I 1  and  12  to flow through the signal line block BKS 2  and the signal line block BKS 1 , respectively. 
     The first detection control circuit  10  switches the operations of the switches SW 25  and SW 26  to change the first voltage VTPH and the second voltage VTPL to be supplied to the lower ends of the signal line blocks BKS 1  and BKS 2  at a predetermined frequency. Thus, the first drive signal VTP serving as the alternating-current voltage signal is supplied to the signal line blocks BKS 1  and BKS 2 . The first detection control circuit  10  sequentially selects the signal lines SGL that serve as the signal line blocks BKS 1  and BKS 2 . As a result, the touch detection is performed over the entire display area AA using the electromagnetic induction method. 
     As described above, the display apparatus  1  includes the first drive signal supply line  52 A that supplies the first voltage VTPH to the signal lines SGL and the second drive signal supply line  54 A that supplies the second voltage VTPL lower than the first voltage VTPH to the signal lines SGL. During the first sensing period, the first coupling switching circuit  16 A couples the first drive signal supply line  52 A to the first end side of at least one of the signal lines SGL, and couples the second drive signal supply line  54 A to the first end sides of the signal lines SGL other than the at least one of the signal lines SGL. During the first sensing period, the second coupling switching circuit  17 A couples the second end sides of the signal lines SGL to one another. 
     Also in the present embodiment, the signal lines SGL forming the transmitting coils CTx are a metal material having a higher electrical conductivity than the detection electrodes  22 . As a result, in the present embodiment, the responsiveness to the first drive signal VTP is increased and the detection sensitivity is improved in the electromagnetic induction touch detection. 
     The first electrodes  67  extend in the first direction Dx, and are arranged in the second direction Dy. First electrode blocks BK 1 , BK 2 , . . . , BK 8  each include a plurality of the first electrodes  67 . The left end of the first electrode block BK 1  is coupled to the left end of the first electrode block BK 3  through first electrode coupling line  67   a  provided in the peripheral area GA. One of the right end of the first electrode block BK 1  and the right end of the first electrode block BK 3  is coupled to the reference potential (for example, the ground potential GND), and the other thereof is coupled to the first detection circuit  11 , through a capacitor CS and a detection signal output line  57 . This configuration causes the first electrode block BK 1 , the first electrode block BK 3 , and the first electrode coupling lines  67   a  to form the receiving coil CRx. 
     In the same manner, the right end of the first electrode block BK 2  is coupled to the right end of the first electrode block BK 5  through the first electrode coupling line  67   a  provided in the peripheral area GA. One of the left end of the first electrode block BK 2  and the left end of the first electrode block BK 5  is coupled to the reference potential (for example, the ground potential GND), and the other thereof is coupled to the first detection circuit  11  through the capacitor CS and the detection signal output line  57 . This configuration causes the first electrode block BK 2 , the first electrode block BK 5 , and the first electrode coupling line  67   a  to form the receiving coil CRx. 
     As illustrated in  FIG. 12 , each of the first electrode blocks BK forming the receiving coils CRx is provided with the capacitor CS. The capacitor CS includes a first capacitor electrode CSE 1  and a second capacitor electrode CSE 2 . The first capacitor electrode CSE 1  and the second capacitor electrode CSE 2  are provided so as to overlap each other in the plan view with a dielectric material (insulating layer  27 ) interposed therebetween. 
     The second capacitor electrode CSE 2  is coupled to an end of the first electrode block BK through relay line  57   a . The first electrodes  67  in the first electrode block BK are coupled together through first electrode coupling line  67   b . The first capacitor electrode CSE 1  is coupled to the detection signal output line  57 . 
     As illustrated in  FIG. 13 , the first electrode  67  is provided between the first substrate  21  and the semiconductor  61  in the display area AA, and extends to the peripheral area GA. The capacitor CS and the detection signal output line  57  are provided in the peripheral area GA. The first capacitor electrode CSE 1  is provided in the same layer as that of the pixel electrode  24  on the insulating layer  27 . The second capacitor electrode CSE 2  is provided in the same layer as that of the detection electrode  22  on the fifth insulating layer  95 . The first capacitor electrode CSE 1  is opposed to the second capacitor electrode CSE 2  with the insulating layer  27  interposed therebetween in the direction orthogonal to the first substrate  21 . This configuration provides capacitance between the first capacitor electrode CSE 1  and the second capacitor electrode CSE 2 . The layers in which the first capacitor electrode CSE 1  and the second capacitor electrode CSE 2  are formed may be reversed. That is, the second capacitor electrode CSE 2  may be formed in the same layer as that of the pixel electrode  24 , and the first capacitor electrode CSE 1  may be formed in the same layer as that of the detection electrode  22 . 
     The second capacitor electrode CSE 2  is coupled to the relay line  57   a  through a contact hole H 11 . The relay line  57   a  is coupled to the first electrode  67  through a contact hole H 13 . The first capacitor electrode CSE 1  is coupled to the detection signal output line  57  through a contact hole H 12 . The detection signal output line  57  and the relay line  57   a  are provided in the same layer as that of the signal line SGL. 
     The above-described configuration provides the capacitor CS between each of the first electrode blocks BK and the first detection circuit  11 . The capacitor CS reduces current leakage of the switching elements Tr, and provides good display performance. 
     Third Embodiment 
       FIG. 14  is a circuit diagram illustrating a coupling configuration of the gate lines and the signal lines according to a third embodiment of the present disclosure.  FIG. 15  is a timing waveform diagram illustrating an operation example of the display apparatus according to the third embodiment. In the present embodiment, during the first sensing period, the gate lines GCL are supplied with the first drive signal VTP from the drive circuit  18  to generate a magnetic field, and an electromotive force due to the magnetic field is generated in the signal lines SGL. That is, the gate lines GCL form the transmitting coils CTx, and the signal lines SGL form the receiving coils CRx. 
     The gate lines GCL extend in the first direction Dx, and are arranged in the second direction Dy. In the following description, a first end of the gate line GCL will be referred to as the left end, and a second end thereof will be referred to as the right end, with reference to  FIG. 14 . Gate line blocks BKG 1 , BKG 2 , . . . , BKGN each include a plurality of the gate lines GCL. 
     The first drive signal supply line  52 , the second drive signal supply line  54 , and the switches SW 11  and SW 12  are provided on the left end sides of the gate lines GCL. The first drive signal supply line  53 , the second drive signal supply line  55 , and the switches SW 13  and SW 14  are provided on the right end sides of the gate lines GCL. The coupling configuration and the operations of these components are the same as those in the example illustrated in  FIG. 8  for the first embodiment. That is, during the first sensing period, the first drive signal supply lines  52  and  53  are coupled to the first end side of at least one of the gate lines GCL, and the second drive signal supply lines  54  and  55  are coupled to the second end side thereof. The second drive signal supply lines  54  and  55  are coupled to the first end sides of the gate lines GCL other than the at least one of the gate lines GCL, and the first drive signal supply lines  52  and  53  are coupled to the second end sides thereof.  FIG. 14  only illustrates some of the switches SW 11 , SW 12 , SW 13 , and SW 14 . The switches SW 11 , SW 12 , SW 13 , and SW 14  are provided for each of the gate lines GCL included in each of the gate line blocks BKG 1 , BKG 2 , . . . , BKGN. 
     In  FIG. 14 , the gate line blocks BKG 2 , BKG 3 , BKG 5 , and BKG 6  form the transmitting coil CTx. During the first sensing period, the first detection control circuit  10  switches the operations of the switches SW 11 , SW 12 , SW 13 , and SW 14  to change the first voltage VTPH and the second voltage VTPL to be supplied to both ends of the gate lines GCL at a predetermined frequency. Thus, the first drive signal VTP serving as the alternating-current voltage signal is supplied to the gate line blocks BKG 2 , BKG 3 , BKG 5 , and BKG 6 . The non-selected gate line blocks BKG 1 , BKG 4 , BKG 7 , . . . , BKGN not selected as the transmitting coil CTx are brought into the floating state. 
     The gate lines GCL are formed of a metal material. For example, copper (Cu) or aluminum (Al) is used as the gate lines GCL. As a result, the responsiveness to the first drive signal VTP is increased and the detection sensitivity is improved in the electromagnetic induction touch detection of the display apparatus  1 . 
     Moreover, first gate drive signal supply line  82  and second gate drive signal supply line  84  are provided on the left end side of the gate lines GCL, and first gate drive signal supply line  83  and second gate drive signal supply line  85  are provided on the right end side thereof. The first gate drive signal supply lines  82  and  83  are wiring that supplies a high-level voltage VGH of the scan signal Vscan (refer to  FIG. 1 ) to the gate lines GCL. The second gate drive signal supply lines  84  and  85  are wiring that supplies a low-level voltage VGL of the scan signal Vscan to the gate lines GCL. 
     During the display period, all the switches SW 11 , SW 12 , SW 13 , and SW 14  are turned off. The gate lines GCL are sequentially coupled to the first gate drive signal supply lines  82  and  83  and the second gate drive signal supply lines  84  and  85  by the gate driver  15 , and are supplied with the scan signal Vscan. 
     During a first sensing period EM, the upper ends of the signal line blocks BKS 1  and BKS 2  are coupled to each other through the switches SW 23  and the signal line coupling line  56 . One of the lower ends of the signal line blocks BKS 1  and BKS 2  is coupled to the reference potential (for example, the ground potential GND), and the other thereof is coupled to the first detection circuit  11 , through the switches SW 21 . As a result, the signal line blocks BKS 1  and BKS 2  and the signal line coupling line  56  form the receiving coil CRx. Although  FIG. 14  illustrates one of the receiving coils CRx, a plurality of the receiving coils CRx may be disposed so as to overlap one another in the same manner as in  FIG. 10 . 
     As illustrated in  FIG. 15 , the display apparatus  1  performs processing during a display period PD, during the first sensing period EM, and during a second sensing period ES in a time-division manner. The display period PD is a period in which the display panel  20  performs the display. The first sensing period EM is a period in which the electromagnetic induction touch detection is performed. The second sensing period ES is a period in which the self-capacitive touch detection is performed. The display apparatus  1  repeats the processing in the display period PD, the first sensing period EM, the second sensing period ES, the display period PD, the first sensing period EM, the second sensing period ES, and so on. However, the order and the number of times of the respective periods can be modified as appropriate. 
     As illustrated in  FIG. 15 , during the display period PD, the scan signal Vscan is supplied from the gate driver  15  to the gate lines GCL. The display control circuit  14  (refer to  FIG. 1 ) supplies the pixel signal Vpix to each of the signal lines SGL. The drive circuit  18  (refer to  FIG. 9 ) supplies the display drive signal Vcomdc to the detection electrodes  22 . These operations cause the display apparatus  1  to perform the display. 
     During the first sensing period EM, the drive circuit  18  supplies the first drive signal VTP to the gate lines GCL forming the transmitting coil CTx. The first drive signal VTP is the alternating-current rectangular wave that alternately repeats the first voltage VTPH and the second voltage VTPL. An electromotive force due to the magnetic field is generated in the signal lines SGL forming the receiving coil CRx. As a result, the first detection signal Vdet 1  is output to the first detection circuit  11 . The detection electrodes  22  are not supplied with a voltage signal, and are placed in a floating state. 
     The first voltage VTPH is a voltage lower than the high-level voltage VGH of the scan signal Vscan. The average value of the first voltage VTPH and the second voltage VTPL equals the low-level voltage VGL. The potential of the gate line GCL is determined by the ratio between the resistance of the gate line GCL and the resistance of the first drive signal supply lines  52 ,  53  and the second drive signal supply lines  54 ,  55  coupled to the gate line GCL. The resistance of the gate line GCL is preferably lower than a resistance value of each line of wiring provided in the peripheral area GA so as to keep the potential of the gate line GCL at an off potential of the switching element Tr. 
     During the second sensing period ES, the drive circuit  18  supplies the second drive signal VSELF to each of the detection electrodes  22 . The detection electrode  22  outputs the second detection signal Vdet 2  corresponding to the self-capacitance of the detection electrode  22  to the second detection circuit  13 . The drive circuit  18  supplies a guard drive signal Vgd to the signal lines SGL. The guard drive signal Vgd is an alternating-current rectangular wave having at least the same amplitude as that of the second drive signal VSELF. For example, the guard drive signal Vgd may be an alternating-current rectangular wave having the same potential and the same phase as those of the second drive signal VSELF. As a result, the display apparatus  1  can restrain the capacitance coupling between the signal lines SGL and the detection electrodes  22 . 
     The timing waveform diagram illustrated in  FIG. 15  is merely an example, and can be modified as appropriate. For example, the display period PD, the first sensing period EM, and the second sensing period ES may differ in length from one another. The order of the display period PD, the first sensing period EM, and the second sensing period ES can be modified as appropriate. The processing in only one of the first sensing period EM and the second sensing period ES may be performed during one frame period. 
     Fourth Embodiment 
       FIG. 16  is a circuit diagram illustrating a coupling configuration of the gate lines and the signal lines according to a fourth embodiment of the present disclosure. In the present embodiment, during the first sensing period, the signal lines SGL are supplied with the first drive signal VTP from the drive circuit  18  to generate a magnetic field, and an electromotive force due to the magnetic field is generated in the gate lines GCL. That is, the signal lines SGL form the transmitting coils CTx, and the gate lines GCL form the receiving coils CRx. 
     As illustrated in  FIG. 16 , the coupling configuration of the signal lines SGL is the same as that in  FIG. 11  for the second embodiment. The signal line blocks BKS 1  and BKS 2  and the signal line coupling line  56  form the transmitting coil CTx. 
     Switches SW 31  and SW 32  are provided on the left end sides of the gate lines GCL. Switches SW 33  and SW 34  are provided on the right end sides of the gate lines GCL. During the first sensing period EM, the switches SW 32  and SW 34  are turned on, and the switches SW 31  and SW 33  are turned off. As a result, the gate lines GCL are coupled to gate line coupling line GCLa or the detection signal output line  57 . 
     Specifically, the left end of the gate line block BKG 1  is coupled to the left end of the gate line block BKG 3  through the gate line coupling line GCLa provided in the peripheral area GA. One of the right end of the gate line block BKG 1  and the right end of the gate line block BKG 3  is coupled to the reference potential (for example, the ground potential GND), and the other thereof is coupled to the first detection circuit  11 , through the detection signal output line  57 . As a result, the gate line block BKG 1 , the gate line block BKG 3 , and the gate line coupling line GCLa form the receiving coil CRx. 
     In the same manner, the right end of the gate line block BKG 2  is coupled to the right end of the gate line block BKGS through the gate line coupling line GCLa provided in the peripheral area GA. One of the left end of the gate line block BKG 2  and the left end of the gate line block BKGS is coupled to the reference potential (for example, the ground potential GND), and the other thereof is coupled to the first detection circuit  11 , through the detection signal output line  57 . As a result, the gate line block BKG 2 , the gate line block BKGS, and the gate line coupling line GCLa form the receiving coil CRx. 
     During the display period PD, the switches SW 31  and SW 33  are turned on, and the switches SW 32  and SW 34  are turned off. As a result, the gate lines GCL are coupled to the first gate drive signal supply lines  82  and  83  or the second gate drive signal supply lines  84  and  85 . 
     Fifth Embodiment 
       FIG. 17  is a plan view schematically illustrating a display apparatus according to a fifth embodiment of the present disclosure. As illustrated in  FIG. 17 , a display apparatus  1 A of the present embodiment includes a common electrode  22 A. The common electrode  22 A is provided over the entire area of the display area AA so as to overlap the pixels Pix. That is, the display apparatus  1 A does not include the detection electrodes  22 , and does not have the self-capacitive touch detection function. 
     The display apparatus  1 A performs the processing during the display period PD and during the first sensing period EM in a time-division manner, without performing the processing during the second sensing period ES. During the display period PD, the drive circuit  18  supplies the display drive signal Vcomdc to the common electrode  22 A. During the first sensing period EM, in the same manner as in any of the first to the fourth embodiments, the transmitting coils CTx and the receiving coils CRx are formed by the first electrodes  67  and the signal lines SGL or by the gate lines GCL and the signal lines SGL, and the electromagnetic induction touch detection is performed. 
     Sixth Embodiment 
       FIG. 18  is a sectional view illustrating a schematic structure of a display apparatus according to a sixth embodiment of the present disclosure. A display apparatus  1 B of the present embodiment is a display panel that uses organic light-emitting diodes (OLEDs) as display elements. That is, the display apparatus  1 B is not provided with a light source such as a backlight. 
     As illustrated in  FIG. 18 , in the display apparatus  1 B, a first substrate  121 , a switching element TrA, a reflective layer  126 , a lower electrode  124 , a self-luminous layer  106  serving as the display layer, an upper electrode  125 , a barrier layer  196 , a filler material  197 , and a second substrate  131  are provided so as to be stacked in the order as listed. 
     The switching element TrA is provided on the first substrate  121 . A semiconductor  161  is provided on the first substrate  121 . A gate electrode  164  (gate line GCLA) is provided on the upper side of the semiconductor  161  with an insulating layer  191  interposed therebetween. A source electrode  162  (signal line SGLA) and a drain electrode  163  are provided on the upper side of the gate electrode  164  with an insulating layer  192  interposed therebetween. The source electrode  162  and the drain electrode  163  are each electrically coupled to the semiconductor  161  through a contact hole. 
     An insulating layer  193  is provided on the insulating layer  192  so as to cover the source electrode  162  and the drain electrode  163 . The reflective layer  126  is provided on the insulating layer  193 , and is formed of a material with a metallic luster that reflects light coming from the self-luminous layer  106 . For example, silver, aluminum, or gold is used as the reflective layer  126 . The lower electrode  124  is provided on the upper side of the reflective layer  126  with an insulating layer  194  interposed therebetween. The self-luminous layer  106  and the upper electrode  125  are provided so as to be stacked on the upper side of the lower electrode  124  in the order as listed. That is, the self-luminous layer  106  is provided between the lower electrode  124  and the upper electrode  125 . 
     The lower electrode  124  is an anode of the organic light-emitting diode and is provided corresponding to each of the pixels Pix. The upper electrode  125  is a cathode of the organic light-emitting diode. A light-transmitting electrically conductive material such ITO is used as the lower electrode  124  and the upper electrode  125 . The self-luminous layer  106  contains a polymeric organic material and includes a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer, which are not illustrated. 
     An insulating layer  195  is an insulating layer that is called a rib and partitions the respective pixels Pix. The barrier layer  196  is provided so as to cover the upper electrode  125  and seals the upper electrode  125 . The filler material  197  is a planarizing layer that reduces unevenness produced by the rib. A color filter  132  is provided between the filler material  197  and the second substrate  131 . 
     With the above-described configuration, the light coming from the self-luminous layer  106  passes through the color filter  132 , and is emitted from the second substrate  131 . Images are displayed on the display surface by controlling the light quantity of the self-luminous layer  106  on a pixel Pix basis. In the display apparatus  1 B, the second substrate  131  may be provided on the filler material  197  without providing the color filter  132 . In this case, in the self-luminous layer  106 , different light-emitting materials are used for the pixels Pix and emit the light in colors of red (R), green (G), and blue (B). 
     The present embodiment is not limited to the above-described configuration. The lower electrode  124  may be a cathode, and the upper electrode  125  may be an anode. In this case, the polarity of the switching element TrA electrically coupled to the lower electrode  124  can be changed as appropriate. 
     Also in the present embodiment, the display apparatus  1 B can form the transmitting coils CTx and the receiving coils CRx using the gate lines GCLA and the signal lines SGLA for the switching elements TrA. The same configuration as that of the third embodiment or the fourth embodiment described above can be applied to the coupling configuration of the transmitting coils CTx and the receiving coils CRx. Alternatively, in the display apparatus  1 B, the first electrode  67  can be provided between the first substrate  121  and the semiconductor  161 , and the transmitting coils CTx and the receiving coils CRx can be formed by the first electrodes  67  and the signal lines SGLA. In this case, the same configuration as that of the third embodiment or the fourth embodiment described above can be applied to the coupling configuration of the transmitting coils CTx and the receiving coils CRx. 
     For example, in the case of the electromagnetic induction touch detection, the drive circuit  18  supplies the first drive signal VTP to the signal lines SGLA. The signal lines SGLA are provided as the transmitting coils CTx, and a magnetic field is generated by the first drive signal VTP. The electromagnetic induction is generated between the signal lines SGLA and the touch pen  100  and between the touch pen  100  and the gate lines GCLA. The electromotive force is generated in the gate lines GCLA by the mutual induction with the touch pen  100 . The first detection signal Vdet 1  corresponding to this electromotive force is supplied from the gate lines GCLA to the first detection circuit  11 . 
     While the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above. The content disclosed in the embodiments is merely an example, and can be variously modified within the scope not departing from the gist of the present disclosure. Any modifications appropriately made within the scope not departing from the gist of the present disclosure naturally belong to the technical scope of the present disclosure. At least one of various omissions, replacements, and modifications of the components can be made without departing from the gist of the above-described embodiments and modifications thereof.