Patent Publication Number: US-2022236820-A1

Title: Display panel with touch sensor function and manufacturing method of display panel with touch panel function

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority to Japanese Patent Application Number 2021-010377 filed on Jan. 26, 2021. The entire contents of the above-identified application are hereby incorporated by reference. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a display panel with a touch sensor function and a manufacturing method of a display panel with a touch sensor function. 
     There have been known display panels with a full in-cell touch sensor function and manufacturing methods of a display panel with a full in-cell touch sensor function. Such a manufacturing method of a display panel with a touch sensor function is disclosed in, for example, WO 2016/136271. 
     In the display panel with a touch sensor function of WO 2016/136271 described above, a pixel electrode, a first insulating film, a sensor electrode line, a second insulating film, a common electrode, a third insulating film, and a data signal line are formed in this order from a liquid crystal layer side. Then, a plurality of slits are provided in the pixel electrode, and the display panel is configured to drive the liquid crystal by generating a transverse electrical field between the pixel electrode in the upper layer and the common electrode in the lower layer. As a result, noise from the data signal line disposed in a lower layer below the common electrode is electrical-field-shielded by the common electrode, preventing the noise from the data signal line from reaching the pixel electrode. 
     Further, in the display panel of WO 2016/136271 described above, the sensor electrode line and the common electrode are connected via a through hole formed in the second insulating film. As a result, a distance between the sensor electrode line and the common electrode can be ensured, making it possible to reduce a parasitic capacitance between the sensor electrode line and the common electrode. Further, the first insulating film is formed covering the sensor electrode line in order to insulate the pixel electrode and the sensor electrode line. Thus, at least the first insulating film and the second insulating film are disposed between the pixel electrode and the common electrode. 
     SUMMARY 
     With the display panel with a touch sensor function set forth in WO 2016/136271 described above, while the noise from the data signal line (data line) can be prevented from reaching the pixel electrode and the parasitic capacitance between the sensor electrode line and the common electrode can be reduced, the first insulating film and the second insulating film are disposed between the pixel electrode and the common electrode. As a result, a distance between the pixel electrode and the common electrode increases, resulting in the problem that a strong electrical field effect on the liquid crystal cannot be acquired, reducing a light transmittance of the display panel (liquid crystal layer). 
     Thus, in order to solve the problems described above, it is an object of the present disclosure to provide a display panel with a touch sensor function and a manufacturing method of a display panel with a touch sensor function that improve a light transmittance of the display panel while preventing noise from a data line from reaching a pixel electrode and reducing a parasitic capacitance between a sensor electrode line (touch sensor line) and a common electrode. 
     To solve the problems described above, a display panel with a touch sensor function according to a first aspect of the present disclosure includes a data line, a common electrode formed in an upper layer above the data line, a first insulating layer covering at least a portion of the common electrode, a touch sensor line formed in an upper layer of the first insulating layer and in a first opening provided in the first insulating layer, and connected to the common electrode via the first opening, a second insulating layer covering at least a portion of the touch sensor line, and a pixel electrode formed in an upper layer of the second insulating layer. The first insulating layer is formed with a second opening between the common electrode and the pixel electrode, the second insulating layer is disposed in an interior of the second opening, and formed with a recessed portion recessed downward into a portion above the second opening, and at least a portion of the pixel electrode is disposed in the recessed portion of the second insulating layer. 
     A manufacturing method of a display panel with a touch sensor function according to a second aspect includes forming a data line on a substrate, forming a common electrode in an upper layer above the data line, forming a first insulating layer covering at least a portion of the common electrode, forming a first opening and a second opening in the first insulating layer, forming a touch sensor line in an upper layer of the first insulating layer and in the first opening provided in the first insulating layer and thus connecting the touch sensor line and the common electrode through the first opening, forming a second insulating layer covering at least a portion of the touch sensor line and in the second opening and thus forming a recessed portion in a portion above the second opening, and forming a pixel electrode in an upper layer of the second insulating layer with at least a portion of the pixel electrode being disposed in the recessed portion of the second insulating layer. 
     According to the configuration described above, a light transmittance of a display panel can be improved, while preventing noise from a data line from reaching a pixel electrode and reducing a parasitic capacitance between a touch sensor line and a common electrode. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating a configuration of a display device according to a first embodiment. 
         FIG. 2  is a plan view of a portion of a display panel. 
         FIG. 3  is a plan view of a first insulating layer according to the first embodiment. 
         FIG. 4  is a cross-sectional view taken along the line  1000 - 1000  in  FIG. 2 . 
         FIG. 5  is a schematic plan view of an active matrix substrate. 
         FIG. 6  is a circuit diagram for explaining a connection relationship between a thin film transistor and a gate line as well as a data line. 
         FIG. 7  is a schematic plan view for explaining a connection between a common electrode and a touch sensor line. 
         FIG. 8  is an enlarged view of a region A 1  in  FIG. 7 . 
         FIG. 9  is a cross-sectional view of the display panel at a position where a touch sensor electrode and the common electrode are not connected. 
         FIG. 10  is a flowchart illustrating a manufacturing process of the display panel according to the first embodiment. 
         FIG. 11  is a diagram illustrating a configuration of a display panel according to a modified example of the first embodiment. 
         FIG. 12  is a plan view illustrating a portion of a configuration of a display panel of a display device according to a second embodiment. 
         FIG. 13  is a plan view of a first insulating layer according to the second embodiment. 
         FIG. 14  is a cross-sectional view taken along the line  1100 - 1100  in  FIG. 12 . 
         FIG. 15  is a diagram illustrating a configuration of a display panel according to a modified example of the second embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals and signs, and the description thereof will not be repeated. Note that, for ease of description, in the drawings referred to below, configurations may be simplified or schematically illustrated, and some components may be omitted. Further, dimensional ratios between components illustrated in the drawings are not necessarily indicative of actual dimensional ratios. 
     First Embodiment 
     A configuration of a display device  100  according to a first embodiment will be described.  FIG. 1  is a block diagram illustrating the configuration of the display device  100  according to the first embodiment. As illustrated in  FIG. 1 , the display device  100  includes a display panel  1  with a touch sensor function (hereinafter referred to as “display panel  1 ”) and a controller  2 . 
     The display panel  1  has a function of displaying a video or an image, and a function of detecting a touch and a touch position from an indicator. The display panel  1  is a full in-cell type touch panel. The controller  2  executes each control process in the display device  100  on the basis of the touch position acquired from the display panel  1 . 
       FIG. 2  is a plan view schematically illustrating a portion of the display panel  1 . Further,  FIG. 3  is a plan view illustrating a configuration of a first insulating layer  11   d  of the display panel  1 . Further,  FIG. 4  is a cross-sectional view taken along the line  1000 - 1000  in  FIG. 2 . As illustrated in  FIG. 4 , the display panel  1  includes an active matrix substrate  10 , a counter substrate  20 , and a liquid crystal layer  30  interposed between the active matrix substrate  10  and the counter substrate  20 . A user visually recognizes an image from a front face (hereinafter, touch surface) side of the counter substrate  20 . Further, the display panel  1  receives a touch operation by, for example, a finger (indicator) on the touch surface. 
     As illustrated in  FIG. 4 , a glass substrate  21 , a black matrix  22 , a color filter  23 , a transparent fixed layer  24 , and an alignment film  25  are disposed on the counter substrate  20  in this order from the touch surface side. An opening  22   a  is provided in the black matrix  22 , and the opening  22   a  functions as a light-transmitting portion that transmits light from the liquid crystal layer  30  side to the touch surface side. 
     Configuration of Active Matrix Substrate 
     As illustrated in  FIG. 4 , the active matrix substrate  10  is provided with a glass substrate  10   a,  a gate line  18  (refer to  FIG. 5 ), a gate insulating layer  11   a,  a data line  12  and a drain electrode  17 , a data line insulating layer  11   b,  an organic insulating layer  11   c,  a common electrode  13 , the first insulating layer  11   d,  a touch sensor line  14  and a connecting electrode  15 , a second insulating layer  11   e,  a pixel electrode  16 , and an alignment film  19 , in this order from the side opposite to the liquid crystal layer  30 . Note that, in the following description, “upper” refers to a Z direction in  FIG. 4 , and refers to the liquid crystal layer  30  side in the active matrix substrate  10 . Further, “lower” refers to the side opposite to the Z direction in  FIG. 4 , and refers to the glass substrate  10   a  side in the active matrix substrate  10 . 
     An electrical field is generated between the pixel electrode  16  and the common electrode  13 , thereby driving the liquid crystal molecules contained in the liquid crystal layer  30 . A plurality of slits  16   a  are provided in the pixel electrode  16 , and the liquid crystal molecules are driven by a transverse electrical field driving method. The common electrode  13  is provided in common to a plurality of the pixel electrodes  16 . Further, the common electrode  13  functions not only as a counter electrode of the pixel electrode  16 , but is connected to the touch sensor line  14  (lower electrode layer  14   a ) and functions as a touch sensor electrode as well. Note that the slit  16   a  provided in the pixel electrode  16  need not necessarily be provided in a plurality to one pixel electrode  16 , and at least one slit  16   a  need only be provided. 
       FIG. 5  is a plan view schematically illustrating a configuration of the active matrix substrate  10 . The active matrix substrate  10  is provided with a gate driver  41  and a source driver  42 . A plurality of the gate lines  18  and a plurality of the data lines  12  intersect each other and are formed in a lattice pattern in plan view. Further, as illustrated in  FIG. 2 , the active matrix substrate  10  is provided with a thin film transistor  50  connected to the plurality of gate lines  18  and the plurality of data lines  12 . 
       FIG. 6  is a schematic circuit diagram for explaining the connection between the thin film transistor  50  and the gate line  18  as well as the data line  12 . As illustrated in  FIG. 6 , a gate electrode of the thin film transistor  50  is connected to the gate line  18 , and a source electrode of the thin film transistor  50  is connected to the data line  12 . Further, the drain electrode  17  of the thin film transistor  50  is connected to the pixel electrode  16 . 
     As illustrated in  FIG. 5 , the plurality of gate lines  18  connect each of the thin film transistors  50  connected to the plurality of pixel electrodes  16  and the gate driver  41 . Further, the plurality of data lines  12  connect each of the thin film transistors  50  connected to the plurality of pixel electrodes  16  and the source driver  42 . Further, the gate driver  41  and the source driver  42  are each disposed in a frame region outside of a display region E 1  in which the plurality of pixel electrodes  16  are disposed. The gate driver  41  and the source driver  42  are constituted by an integrated circuit, for example. The gate driver  41  supplies gate signals (scanning signals) sequentially to each of the plurality of gate lines  18 . Specifically, the gate driver  41  sequentially applies voltage to (scans) the plurality of gate lines  18  on the basis of a horizontal synchronization signal from the controller  2 . The source driver  42  supplies a data signal (source signal) to each of the plurality of data lines  12 . 
       FIG. 7  is a plan view schematically illustrating the configuration of the active matrix substrate  10  in a layer different from that in  FIG. 5 . The active matrix substrate  10  includes a touch detection driver  43 . The touch detection driver  43  is constituted by an integrated circuit, for example. The touch detection driver  43  and the common electrodes  13  are respectively connected via the touch sensor line  14 . The touch detection driver  43  transmits a drive signal to each of the common electrodes  13  and receives a signal from each of the common electrodes  13 . Then, the touch detection driver  43  detects a touch position by an indicator (a finger, for example) on the basis of the received signal. 
       FIG. 8  is an enlarged view of a region A 1  in  FIG. 7 . As illustrated in  FIG. 8 , the touch sensor line  14  is connected to the common electrode  13  at a plurality of locations (openings  64 ). Further, a dummy wiring line  14   c  is provided in an upper layer above the common electrode  13  at a position different from that of the touch sensor line  14  in plan view. The dummy wiring line  14   c  extends parallel to the touch sensor line  14  and is not directly connected to the touch detection driver  43 . Note that the state in which the dummy wiring line  14   c  is not directly connected to the touch detection driver  43  includes a state in which, for example, the dummy wiring line  14   c  is electrically connected to the touch detection driver  43  with the common electrode  13  and the touch sensor line  14  interposed therebetween. Further, the touch sensor line  14  is disposed across the plurality of common electrodes  13  while the dummy wiring line  14   c  is disposed on a single common electrode  13 . The plurality of lines of the dummy wiring line  14   c  and the touch sensor line  14  are formed in the same manufacturing process. Then, lines of the plurality of lines other than the lines that function as the touch sensor lines  14  are cut at boundaries of the plurality of common electrodes  13 , thereby forming the dummy wiring lines  14   c.  As a result, the common electrode  13  and a plurality of the dummy wiring lines  14   c  connected to the common electrode  13  can be made electrically independent from the dummy wiring lines  14   c  of the other common electrodes  13 . 
     Then, the dummy wiring line  14   c  is constituted by, for example, copper (Cu) having a resistance value smaller than that of indium tin oxide (ITO) of the common electrode  13 . Then, the dummy wiring line  14   c  and the common electrode  13  are connected via the opening  64 . As a result, when the dummy wiring line  14   c  and the common electrode  13  are viewed as one segment, the resistance value of the segment can be made small compared to a case in which the dummy wiring line  14   c  is not provided. Further, as illustrated in  FIG. 8 , the plurality of dummy wiring lines  14   c  are disposed in parallel at equal intervals and in alignment with the touch sensor line  14  on the common electrode  13 . In this way, differences in the shapes of the common electrodes  13  in plan view can be reduced. Specifically, in each of the common electrodes  13 , the touch sensor line  14  and the plurality of dummy wiring lines  14   c  are similarly disposed in parallel, and thus the shape of the light-transmitting portion between the touch sensor line  14  and the dummy wiring line  14   c,  and the shape of the light-transmitting portion between the plurality of dummy wiring lines  14   c  are equal to each other. As a result, an optical difference (transmittance change) of each line (RGB pixel) can be eliminated, and a color shift can be prevented. This effect is particularly significant when viewing the common electrode  13  from a planar oblique direction. 
     Configuration of Each Layer in Active Matrix Substrate 
     As illustrated in  FIG. 4 , the gate insulating layer  11   a  is formed in an upper layer of the glass substrate  10   a.  The gate insulating layer  11   a  is formed covering the gate line  18  (refer to  FIG. 5 ). The gate insulating layer  11   a  is formed of an inorganic insulating film, and is formed of, for example, silicon nitride (SiNx) or silicon oxide (SiO 2 ). Further, the gate line  18  is formed of a metal film. 
     The data line  12  and the drain electrode  17  are formed over the gate insulating layer  11   a  and are formed of a metal film. 
     The data line insulating layer  11   b  is formed covering the data line  12  and the drain electrode  17 . The data line insulating layer  11   b  is formed of an inorganic insulating film, and is formed of, for example, silicon nitride (SiNx) or silicon oxide (SiO 2 ). An opening  61   a  in which a portion of the connecting electrode  15  formed in the same layer as that of the touch sensor line  14  is disposed is provided in the data line insulating layer  11   b  above the drain electrode  17 . The opening  61   a  is formed in a position that does not overlap the opening  22   a  of the black matrix  22  in plan view. 
     The organic insulating layer  11   c  is formed on the data line insulating layer  11   b.  Further, a thickness of the organic insulating layer  11   c  is preferably not less than 1 μm and not greater than 4 μm. Here, the thicker the organic insulating layer  11   c,  the greater the insulating performance and the smaller the parasitic capacitance between the data line  12  and the common electrode  13 , making it possible to improve the sensitivity of the touch panel. In this regard, the film thickness of the organic insulating layer  11   c  is preferably 1 μm or greater. However, as a disadvantage of making the thickness thicker, patterning becomes difficult, and thus the film thickness of the organic insulating layer  11   c  is preferably 4 μm or less. Further, an opening  62  in which a portion of the first insulating layer  11   d  is disposed is provided in the organic insulating layer  11   c  above the drain electrode  17 . 
     The common electrode  13  is formed on the organic insulating layer  11   c.  The common electrode  13  is formed of, for example, a transparent conductive film (indium tin oxide (ITO), for example). The common electrode  13  is formed in an upper layer above the data line  12  and in a lower layer below the pixel electrode  16 . Further, the common electrode  13  is provided with an opening  13   a  in which the first insulating layer  11   d  is disposed. The opening  13   a  is formed in a position overlapping the openings  61   a  and  61   b,  the opening  62 , and an opening  65  in plan view, as illustrated in  FIG. 2 . 
     As illustrated in  FIG. 4 , the first insulating layer  11   d  covers at least a portion of the common electrode  13 , and is formed in the opening  13   a  and in the opening  62 . The first insulating layer  11   d  is formed of an inorganic insulating film, and is formed of, for example, silicon nitride (SiNx) or silicon oxide (SiO 2 ).  FIG. 9  is a cross-sectional view of the active matrix substrate  10  at a position different in plan view from that of  FIG. 4 . As illustrated in  FIG. 9 , the first insulating layer  11   d  has a function of insulating the common electrode  13  and the touch sensor line  14  not connected to the common electrode  13 . Further, a film thickness of the first insulating layer  11   d  is preferably not less than 150 nm and not greater than 500 nm. Here, the thicker the first insulating layer  11   d,  the greater the insulating performance and the smaller the parasitic capacitance between the common electrode  13  and the touch sensor line  14  not connected to the common electrode  13 , making it possible to improve the sensitivity of the touch panel. In this regard, the film thickness of the first insulating layer  11   d  is preferably 150 nm or greater. However, as a disadvantage of making the thickness thicker, patterning becomes difficult, and thus the film thickness of the first insulating layer  11   d  is preferably 500 nm or less. Further, in the first embodiment, an opening  63  in which the second insulating layer  11   e  is disposed is formed in the first insulating layer  11   d,  between the common electrode  13  and the pixel electrode  16 . 
     Further, the opening  61   b  is formed above the drain electrode  17  in the first insulating layer  11   d.  The opening  61   b  is continuous in a vertical direction with the opening  61   a  of the data line insulating layer  11   b.  Further, as illustrated in  FIG. 4 , the opening  64  in which a portion of the touch sensor line  14  connected to the common electrode  13  is disposed is formed in the first insulating layer  11   d  above the common electrode  13 . Further, as illustrated in  FIG. 3 , the opening  61   b,  the opening  63 , and the opening  64  are formed separately from each other in plan view. Further, as illustrated in  FIG. 4 , the opening  63  is not provided in a portion where the common electrode  13  is not disposed in plan view. As a result, in a portion where the common electrode  13  is not disposed, the distance between the data line  12  and the pixel electrode  16  is small, making it possible to prevent the parasitic capacitance between the data line  12  and the pixel electrode  16  from becoming large. 
     As illustrated in  FIG. 4 , the touch sensor line  14  is formed in an upper layer of a portion of the first insulating layer  11   d  and in the opening  64  in the first insulating layer  11   d.  Then, the touch sensor line  14  is connected to the common electrode  13  via the opening  64 . Further, in plan view, the touch sensor line  14  is connected to one common electrode  13  (refer to  FIG. 7 ) of the plurality of common electrodes  13 , and is not connected to the other common electrodes  13 . 
     Here, in a direction orthogonal to a thickness direction (Z direction) of the display panel  1  and in a width direction (X direction) orthogonal to a direction in which the touch sensor line  14  extends (Y direction), a length (width) W 1  of the touch sensor line  14  is not greater than a length (width) W 2  of the first insulating layer  11   d.  In the example of  FIG. 4 , the width W 1  is less than the width W 2 , and a length (width) W 3  of the first insulating layer  11   d  from the touch sensor line  14  to the opening  63  is greater than a dimension equivalent to four-ninths of the width W 1 , for example. According to this configuration, when the touch sensor line  14  is formed on the first insulating layer  11   d,  a shift in the touch sensor line  14  can be absorbed to the extent that the width W 2  of the first insulating layer  11   d  is large. That is, the touch sensor line  14  can be easily aligned. Further, in the first embodiment, a width W 4  of the opening  63  in the X direction is greater than a width W 5  of a first portion  16   b  of the pixel electrode  16 . 
     Further, the touch sensor line  14  is formed parallel to the data line  12 , and a width W 6  of the data line  12  is not greater than the width W 1  of the touch sensor line  14 . In the example of  FIG. 4 , the width W 6  is less than the width W 1 . According to this configuration, the width W 6  of the data line  12  is small, making it difficult for multiple reflection to occur between the touch sensor line  14  and the data line  12 . As a result, unnecessary light transmission is reduced, making it possible to improve the contrast of the display panel  1  and suppress the occurrence of color unevenness. 
     Further, the touch sensor line  14  includes, for example, the lower electrode layer  14   a  and an upper electrode layer  14   b.  The lower electrode layer  14   a  and the upper electrode layer  14   b  are layered. The lower electrode layer  14   a  is disposed in the opening  64 . The lower electrode layer  14   a  has a light reflectivity less than that of the upper electrode layer  14   b.  For example, the lower electrode layer  14   a  includes titanium (Ti). The upper electrode layer  14   b  includes, for example, copper (Cu). According to this configuration, the light reflection at the lower electrode layer  14   a  can be reduced, making it possible to suppress multiple reflection between the data line  12  and the touch sensor line  14  of light (backlight) incident from below the display panel  1 . As a result, unnecessary coloring (color mixing) can be prevented when the display panel  1  is viewed obliquely from above. Thus, the size of the black matrix  22  required for color mixing prevention can be reduced, and the light transmittance of the display panel  1  can be further improved without reducing display quality. 
     The connecting electrode  15  has a function of electrically connecting the drain electrode  17  and the pixel electrode  16 . The connecting electrode  15  is formed in an upper layer of a portion of the first insulating layer  11   d,  and in the opening  61   b  provided in the first insulating layer  11   d  and the opening  61   a  in the data line insulating layer  11   b.  Then, the connecting electrode  15  is connected to the drain electrode  17  via the openings  61   a  and  61   b.  Further, the connecting electrode  15  includes, for example, a lower electrode layer  15   a  and an upper electrode layer  15   b.  The lower electrode layer  15   a  and the upper electrode layer  15   b  are layered. The lower electrode layer  15   a  is formed in the same layer as that of the lower electrode layer  14   a  of the touch sensor line  14  and is formed of the same material. The upper electrode layer  15   b  is formed in the same layer as the upper electrode layer  14   b  of the touch sensor line  14  and is formed of the same material. 
     The second insulating layer  11   e  is formed covering at least a portion of the touch sensor line  14  and at least a portion of the connecting electrode  15 . The second insulating layer  11   e  is formed of an inorganic insulating film, and is formed of, for example, silicon nitride (SiNx) or silicon oxide (SiO 2 ). Further, a film thickness of the second insulating layer  11   e  is preferably not less than 150 nm and not greater than 500 nm. Here, the thicker the film thickness of the second insulating layer  11   e,  the greater the insulating performance between the pixel electrode  16  and the touch sensor line  14 . In this regard, the film thickness of the second insulating layer  11   e  is preferably 150 nm or greater. However, as a disadvantage of making the thickness thicker, patterning becomes difficult, and thus the film thickness of the second insulating layer  11   e  is preferably 500 nm or less. Further, because the film thicknesses of the first insulating layer  11   d  and the second insulating layer  11   e  can be adjusted independently, it is easy to achieve both touch panel performance and a panel transmittance design. Then, in order to form the first insulating layer  11   d  and the second insulating layer  11   e,  it is not necessary to use a special process, making it possible to improve the yield of the display panel  1 . 
     Further, a portion of the second insulating layer  11   e  is formed in the opening  63  of the first insulating layer  11   d  and is in contact with the common electrode  13 . Then, a recessed portion  70  recessed downward into a portion  63   a  above the opening  63  is formed in the second insulating layer  11   e.  As a result, a distance D 1  from a bottom face of the recessed portion  70  to an upper face of the common electrode  13  is smaller than a distance D 2  from an upper face of the second insulating layer  11   e  to the upper face of the common electrode  13  in a portion  63   b  different from the portion  63   a  of the second insulating layer  11   e.  Further, in the second insulating layer  11   e,  the opening  65  in which a second portion  16   c  of the pixel electrode  16  is disposed is formed above the connecting electrode  15 . 
     The pixel electrode  16  is formed in an upper layer of the second insulating layer  11   e.  As a result, the common electrode  13  is disposed between the data line  12  and the pixel electrode  16 , and thus noise from the data line  12  is shielded by the common electrode  13 . As a result, the noise from the data lines  12  can be prevented from reaching the pixel electrode  16 . Then, because noise can be prevented from reaching the pixel electrode  16 , an area of the pixel electrode  16  can be increased. As a result, the light transmittance of the display panel  1  can be improved. Further, because the first insulating layer  11   d  is disposed between the touch sensor line  14  and the common electrode  13 , the parasitic capacitance between the touch sensor line  14  and the common electrode  13  can be reduced. Further, the pixel electrode  16  is formed of, for example, a transparent conductive film (ITO, for example). 
     Further, at least a portion of the pixel electrode  16  (first portion  16   b ) is disposed in the recessed portion  70  of the second insulating layer  11   e.  As a result, a distance between the first portion  16   b  of the pixel electrode  16  and the common electrode  13  is the distance D 1 , which is smaller than the distance D 2  described above. Furthermore, the plurality of slits  16   a  provided in the pixel electrode  16  are all disposed in the recessed portion  70  of the second insulating layer  11   e.  According to this configuration, the electrical field effect produced through the slits  16   a  between the first portion  16   b  of the pixel electrode  16  and the common electrode  13  can be increased to the extent that the distance D 1  between the first portion  16   b  of the pixel electrode  16  and the common electrode  13  is small. As a result, the light transmittance of the display panel  1  can be improved. Note that the entire region of the plurality of slits  16   a  provided in the pixel electrode  16  is more preferably disposed in the recessed portion  70  of the second insulating layer  11   e,  but the slit  16   a  does not necessarily have to be disposed in the recessed portion  70  of the second insulating layer  11   e  in a region that does not substantially contribute to the display, for example, in a region where the slit  16   a  and the black matrix  22  overlap in a plan view. 
     The second portion  16   c  of the pixel electrode  16  is connected to the drain electrode  17  of the thin film transistor  50  via the connecting electrode  15 . Further, a portion of the second portion  16   c  is disposed in the opening  65  of the second insulating layer  11   e  and is in contact with the upper electrode layer  15   b  of the connecting electrode  15 . According to this configuration, the connecting electrode  15  for connecting the drain electrode  17  and the pixel electrode  16  can be formed in conjunction with the process of forming the touch sensor line  14  (steps S 11  and S 12  described below). As a result, the number of processes for connecting the thin film transistor  50  and the pixel electrode  16  can be reduced. 
     Manufacturing Method of Display Panel with Touch Sensor Function 
     Next, a manufacturing method of the display panel  1  according to the first embodiment will be described with reference to  FIG. 10 .  FIG. 10  illustrates a flowchart of each manufacturing process of the display panel  1 . 
     In step S 1 , the gate lines  18  are formed on the glass substrate  10   a.  In step S 2 , the gate insulating layer  11   a  is formed covering the gate lines  18 . 
     In step S 3 , a semiconductor layer  51  is formed in an upper layer of the gate insulating layer  11   a  and, in step S 4 , the data lines  12  and the drain electrode  17  are formed in an upper layer of the semiconductor layer  51 . In step S 5 , the data line insulating layer  11   b  is formed covering the data lines  12  and the drain electrode  17 . 
     In step S 6 , the organic insulating layer  11   c  is formed on the data line insulating layer  11   b.  In step S 7 , the opening  62  is formed in a portion of the organic insulating layer  11   c  above the drain electrode  17 . 
     In step S 8 , the common electrode  13  is formed on the organic insulating layer  11   c.  In step S 9 , the first insulating layer  11   d  is formed covering at least a portion of the common electrode  13  and filling the opening  62 . 
     Then, in the first embodiment, in step S 10 , the opening  63  is formed in a portion of the first insulating layer  11   d  between the common electrode  13  and the pixel electrode  16 . Further, in this step S 10 , the opening  61   a  is formed in a portion of the data line insulating layer  11   b  above the drain electrode  17 , and the opening  61   b  is formed in a portion of the first insulating layer  11   d  above the drain electrode  17 . Further, in this step S 10 , the opening  64  is formed above the common electrode  13  in the first insulating layer  11   d.    
     In step S 11 , the lower electrode layer  14   a  of the touch sensor line  14  is formed in an upper layer of a portion of the first insulating layer  11   d  and in the opening  64  in the first insulating layer  11   d.  In this step S 11 , the lower electrode layer  15   a  of the connecting electrode  15  is formed in an upper layer of a portion of the first insulating layer  11   d,  in the opening  61   a  in the data line insulating layer  11   b,  and in the opening  61   b  of the first insulating layer  11   d.    
     In step S 12 , the upper electrode layer  14   b  of the touch sensor line  14  is formed on the lower electrode layer  14   a.  As a result, the touch sensor line  14  that connects the touch sensor line  14  and the common electrode  13  through the opening  64  is formed. Further, in this step S 12 , the upper electrode layer  15   b  of the connecting electrode  15  is formed on the lower electrode layer  15   a.  As a result, the connecting electrode  15  that connects the drain electrode  17  and the pixel electrode  16  through the openings  61   a  and  61   b  is formed. 
     In step S 13 , the second insulating layer  11   e  is formed covering at least a portion of the touch sensor line  14  and at least a portion of the connecting electrode  15 . Further, in this step S 13 , a portion of the second insulating layer  11   e  is formed in the opening  63  of the first insulating layer  11   d,  and this portion of the second insulating layer  11   e  is in contact with the common electrode  13 . Then, the second insulating layer  11   e  is formed in the opening  63  of the first insulating layer  11   d,  thereby forming the recessed portion  70  recessed downward into the portion  63   a  above the opening  63 . 
     In step S 14 , the opening  65  is formed above the connecting electrode  15  in the second insulating layer  11   e.  In step S 15 , the pixel electrode  16  is formed in an upper layer of the second insulating layer  11   e.  In this step S 15 , at least a portion of the pixel electrode  16  (first portion  16   b ) is disposed in the recessed portion  70  of the second insulating layer  11   e.  Further, in this step S 15 , the second portion  16   c  of the pixel electrode  16  is formed in an upper layer of the second insulating layer  11   e  and above the connecting electrode  15 . A portion of the second portion  16   c  is disposed in the opening  65  of the second insulating layer  11   e.  In this manner, the active matrix substrate  10  is manufactured. Subsequently, the active matrix substrate  10 , the counter substrate  20 , and the liquid crystal layer  30  are combined, thereby completing the display panel  1 . 
     According to the manufacturing method described above, noise from the data line  12  can be prevented from reaching the pixel electrode  16 , and the parasitic capacitance between the touch sensor line  14  and the common electrode  13  can be reduced. Then, at least a portion of the pixel electrode  16  is formed in the recessed portion  70 , making it possible to reduce the distance D 1  between the pixel electrode  16  disposed in the recessed portion  70  and the common electrode  13  and thus produce a strong electrical field effect. As a result, the light transmittance of the display panel  1  can be improved. 
     Modified Example of First Embodiment 
     Next, a configuration and a manufacturing method of a display panel  201  with a touch sensor function, which is a modified example of the display panel  1  according to the first embodiment, will be described with reference to  FIG. 11 . In the first embodiment described above, the openings  61   b,    63 , and  64  provided in the first insulating layer  11   d  are formed separately in plan view. However, as illustrated in  FIG. 11 , an integral opening  260  is formed in a first insulating layer  211   d  of the display panel  201  of the present modified example. That is, in step S 10  in the manufacturing method of the first embodiment described above, one opening  260  is formed. According to this configuration and manufacturing method, the number of openings formed in the first insulating layer  211   d  is reduced, making it possible to simplify the configuration of the display panel  201 . 
     Second Embodiment 
     Next, a configuration of a display device  300  including a display panel  301  with a touch sensor function (hereinafter referred to as “display panel  301 ”) according to a second embodiment will be described with reference to  FIG. 12  to  FIG. 14 . In the display device  300  according to the second embodiment, unlike the configuration of the first embodiment in which, in the width direction (X direction), the entire portion of the pixel electrode  16  excluding the second portion  16   c,  which is the connecting portion with the connecting electrode  15 , is disposed in the recessed portion  70 , a first portion  316   b  of a pixel electrode  316  is disposed in the recessed portion  370 , and a third portion  316   a  of the pixel electrode  316  is disposed outside the recessed portion  370 , at a position between the recessed portion  370  and the touch sensor line  14  in plan view. Note that, in the following description, when the same reference numerals as in the first embodiment are used, the same configurations as in the first embodiment are indicated, and reference is made to the preceding description unless otherwise described. 
     Configuration of Display Device According to Second Embodiment 
       FIG. 12  is a plan view of a portion of the display panel  301  of the display device  300 .  FIG. 13  is a plan view of a first insulating layer  311   d  of the display panel  301 . As illustrated in  FIG. 13 , the display panel  301  is provided with the pixel electrode  316  and an opening  363  formed in the first insulating layer  311   d.    
       FIG. 14  is a cross-sectional view taken along the line  1100 - 1100  in  FIG. 12 . The pixel electrode  316  of the display panel  301  includes the first portion  316   b,  a second portion  316   c,  and the third portion  316   a.  The first portion  316   b  is disposed in the recessed portion  370  of a second insulating layer  311   e.  The second portion  316   c  is formed above the connecting electrode  15 . The third portion  316   a  is formed in an upper layer of the second insulating layer  311   e,  at a position between the recessed portion  370  and the touch sensor line  14  and at a position between the recessed portion  370  and the connecting electrode  15 . 
     Here, a distance D 3  between the third portion  316   a  and the touch sensor line  14  is smaller than the distance D 2  between the third portion  316   a  (upper face of the second insulating layer  11   e ) and the common electrode  13 . Here, during the period when the pixel electrode  316  is driven, a signal (COM signal) supplied to the common electrode  13  is supplied to the touch sensor line  14  as well, and thus the touch sensor line  14  and the common electrode  13  are at the same potential, and the touch sensor line  14  functions as a portion of the common electrode  13 . As a result, an electrical field for driving the liquid crystal of the liquid crystal layer  30  is generated between the third portion  316   a  and the touch sensor line  14 . 
     According to the configuration of the second embodiment described above, the area of the pixel electrode  316  can be made larger compared to a case in which the pixel electrode  316  is formed only in the recessed portion  370 . Further, even when the distance D 2  between the third portion  316   a  of the pixel electrode  316  and the common electrode  13  is long, an electrical field is generated between the third portion  316   a  and the touch sensor line  14 , making it possible to further improve the light transmittance of the display panel  301  (liquid crystal layer  30 ). Note that the other configurations and effects of the display device  300  according to the second embodiment are the same as the configurations and effects of the display device  100  according to the first embodiment. 
     Manufacturing Method of Display Panel According to Second Embodiment 
     In the manufacturing method of the display panel  301  according to the second embodiment, in step S 15  in the manufacturing process of the display panel  1  according to the first embodiment illustrated in  FIG. 10 , the third portion  316   a  of the pixel electrode  316  is formed in an upper layer of the second insulating layer  11   e,  between the recessed portion  370  and the touch sensor line  14  in plan view, in addition to formation of the first portion  316   b  of the pixel electrode  316  in the recessed portion  370 . Note that the other manufacturing processes of the display panel  301  according to the second embodiment are the same as the manufacturing processes of the display panel  1  according to the first embodiment. 
     Modified Example of Second Embodiment 
     Next, a configuration and a manufacturing method of a display panel  401  with a touch sensor function, which is a modified example of the display panel  301  according to the second embodiment, will be described with reference to  FIG. 15 . As illustrated in  FIG. 13 , in the second embodiment described above, the opening  61   b  and the opening  363  provided in the first insulating layer  311   d  are formed separately in plan view. However, as illustrated in  FIG. 15 , an integral opening  463  is formed in a first insulating layer  411   d  of the display panel  401  of the present modified example. That is, in step S 10  in the manufacturing method of the first embodiment, the integral opening  463  is formed. According to this configuration and manufacturing method, the number of openings formed in the first insulating layer  411   d  is reduced, making it possible to simplify the configuration of the display panel  401 . 
     Modifications and the Like 
     The above-described embodiments are merely examples for carrying out the present disclosure. Accordingly, the present disclosure is not limited to the embodiments described above and can be implemented by modifying the embodiments described above as appropriate without departing from the scope of the present disclosure. 
     For example, in the first and second embodiments described above, examples are illustrated in which the first insulating layer and the second insulating layer are constituted by an inorganic insulating film, but the present disclosure is not limited to such examples. That is, the first insulating layer and the second insulating layer may be constituted by an organic insulating film. Further, the first insulating layer and the second insulating layer may be configured by layering a plurality of inorganic insulating films, such as by layering silicon nitride (SiNx) and silicon oxide (SiO2), for example. 
     Further, in the first and second embodiments described above, examples are given of the materials of the data line, the common electrode, the touch sensor line, the first connecting electrode, the second connecting electrode, and the pixel electrode, but the present disclosure is not limited to those materials. The data line, the common electrode, the touch sensor line, the first connecting electrode, the second connecting electrode, and the pixel electrode may be configured using materials other than the materials described above. 
     Further, although an example in which the touch sensor line is constituted by two layers is illustrated in the first and second embodiments described above, the present disclosure is not limited to this example. That is, the touch sensor line may be constituted by a single layer, or may be configured as a layered film of three or more layers. 
     Further, although an example in which the width W 6  of the data line is not greater than the width W 1  of the touch sensor line is illustrated in the first to second embodiments described above, the present disclosure is not limited to this example. That is, the width of the data line may be greater than the width of the touch sensor line. 
     Further, the display panel with a touch sensor function and the manufacturing method of a display panel with a touch sensor function described above can be described as follows. 
     A display panel with a touch sensor function according to a first configuration includes a data line, a common electrode formed in an upper layer above the data line, a first insulating layer covering at least a portion of the common electrode, a touch sensor line formed in an upper layer of the first insulating layer and in a first opening provided in the first insulating layer, and connected to the common electrode via the first opening, a second insulating layer covering at least a portion of the touch sensor line, and a pixel electrode formed in an upper layer of the second insulating layer. The first insulating layer is formed with a second opening between the common electrode and the pixel electrode, the second insulating layer is disposed in an interior of the second opening, and the second insulating layer is formed with a recessed portion recessed downward into a portion above the second opening, and at least a portion of the pixel electrode is disposed in the recessed portion of the second insulating layer 
     (First Configuration). 
     According to the first configuration described above, the common electrode is disposed between the data line and the pixel electrode, and thus noise from the data line is shielded by the common electrode. This makes it possible to prevent noise from the data line from reaching the pixel electrode. Then, because noise can be prevented from reaching the pixel electrode, an area of the pixel electrode can be increased. As a result, the light transmittance of the display panel can be improved. Then, because the first insulating layer is disposed between the touch sensor line and the common electrode, the parasitic capacitance between the touch sensor line and the common electrode can be reduced. Then, at least a portion of the pixel electrode is disposed in the recessed portion of the second insulating layer, making it possible to reduce a distance between the pixel electrode disposed in the recessed portion and the common electrode and thus produce a strong electrical field effect. As a result, the light transmittance of the display panel can be improved. 
     In the first configuration, the pixel electrode may be provided with a slit, and the slit may be formed in the pixel electrode disposed in the recessed portion of the second insulating layer. Second Configuration 
     According to the second configuration described above, in the display panel in which the pixel electrode is provided with a slit, the distance between the pixel electrode disposed in the recessed portion and the common electrode can be reduced, making it possible to strengthen the electrical field effect produced between the pixel electrode and the common electrode through the slit. As a result, the light transmittance of the display panel that drives liquid crystal by utilizing a transverse electrical field generated at the slit portion can be improved. 
     In the first or second configuration, the touch sensor line may include a first touch sensor layer and a second touch sensor layer formed in a lower layer of the first touch sensor layer and having a light reflectivity less than a reflectivity of the first touch sensor layer (Third configuration). 
     According to third configuration described above, the light reflectance at the second touch sensor layer can be reduced, making it possible to suppress multiple reflection between the data line and the touch sensor line of light (backlight) incident from below the display panel. As a result, unnecessary coloring (color mixing) can be prevented when the display panel is viewed obliquely from above. Thus, the size of the black matrix required for color mixing prevention can be reduced, and the light transmittance of the display panel can be further improved without reducing display quality. 
     In any one of the first to third configurations, the display panel with a touch sensor function may further include a drain electrode formed in the same layer as a layer of the data line, and a connecting electrode configured to connect the drain electrode and the pixel electrode. The first insulating layer may be formed with a third opening above the drain electrode, and the connecting electrode may be formed in the third opening in the same layer as a layer of the touch sensor line (Fourth configuration). 
     According to the fourth configuration described above, the connecting electrode for connecting the drain electrode to the pixel electrode can be formed in conjunction with formation of the touch sensor line. As a result, the number of processes for connecting the drain electrode to the pixel electrode can be reduced. 
     In the fourth configuration, at least two of the first opening, the second opening, and the third opening of the first insulating layer may be continuously formed in plan view (Fifth configuration). 
     According to the fifth configuration described above, the number of openings formed in the first insulating layer is reduced, making it possible to simplify the configuration of the first insulating layer. 
     In any one of the configurations of the first to fifth configurations, the touch sensor line may be formed in a linear shape and, in a width direction of the touch sensor line, the touch sensor line may have a length less than or equal to a length of the first insulating layer (Sixth configuration). 
     According to the sixth configuration described above, when the touch sensor line is formed on the first insulating layer, a shift in the touch sensor line can be absorbed to the extent that the length (width) of the first insulating layer is long (large). That is, the touch sensor line can be easily aligned. 
     In any one of the configurations of the first to sixth configurations, the touch sensor line may be formed in a linear shape, the data line may be formed parallel to the touch sensor line and in a linear shape and, in a width direction of the data line, the data line may have a length less than or equal to a length of the touch sensor line (Seventh configuration). 
     According to the seventh configuration described above, the length (width) of the data line is short (small), making it difficult for multiple reflection to occur between the touch sensor line and the data line. As a result, unnecessary light transmission is reduced, making it possible to improve the light transmittance of the display panel. 
     In any one of the first to seventh configurations, the pixel electrode may be formed in the recessed portion as well as in an upper layer of the second insulating layer, between the recessed portion and the touch sensor line, in plan view (Eighth configuration). 
     According to the eighth configuration described above, the area of the pixel electrode can be made larger compared to a case in which the pixel electrode is formed only in the recessed portion. Here, during the period when the pixel electrode is driven, a signal supplied to the common electrode is supplied to the touch sensor line as well (the touch sensor line and the common electrode are at the same potential), and thus the touch sensor line functions as a portion of the common electrode. As a result, an electrical field is generated between the pixel electrode formed in an upper layer of the second insulating layer and the touch sensor line formed in an upper layer above the second insulating layer. Thus, even in a case in which the distance between the portion of the pixel electrode formed in an upper layer of the second insulating layer and the common electrode is long, an electrical field is generated between the portion formed in the upper layer of the second insulating layer and the touch sensor line, making it possible to further improve the light transmittance of the display panel (liquid crystal layer). 
     A manufacturing method of a display panel with a touch sensor function according to a ninth configuration includes forming a data line on a substrate, forming a common electrode in an upper layer above the data line, forming a first insulating layer covering at least a portion of the common electrode, forming a first opening and a second opening in the first insulating layer, forming a touch sensor line in an upper layer of the first insulating layer and in the first opening provided in the first insulating layer and thus connecting the touch sensor line and the common electrode through the first opening, forming a second insulating layer covering at least a portion of the touch sensor line and in the second opening and thus forming a recessed portion in a portion above the second opening, and forming a pixel electrode in an upper layer of the second insulating layer with at least a portion of the pixel electrode being disposed in the recessed portion of the second insulating layer (Ninth configuration). 
     According to the ninth configuration described above, as with the first configuration described above, noise from the data line can be prevented from reaching the pixel electrode, and the parasitic capacitance between the touch sensor line and the common electrode can be reduced. Then, at least a portion of the pixel electrode is formed in the recessed portion of the second insulating layer, making it possible to reduce a distance between the pixel electrode disposed in the recessed portion and the common electrode, and thus produce a strong electrical field effect. As a result, the light transmittance of the display panel can be improved. 
     In the ninth configuration, the manufacturing method may further include forming a third opening after the formation of the first insulating layer and before the formation of the touch sensor line. The formation of the data line may further include forming a drain electrode, the third opening may be formed above the drain electrode in the first insulating layer, the formation of the touch sensor line may further include forming a connecting electrode connected to the drain electrode in the same layer as a layer of the touch sensor line, and the formation of the pixel electrode may include forming the pixel electrode with the pixel electrode connected to the connecting electrode (Tenth configuration). 
     According to the tenth configuration described above, the connecting electrode for connecting the drain electrode to a member in an upper layer can be formed in conjunction with the process of forming the touch sensor line. As a result, the number of processes for connecting the drain electrode to the pixel electrode can be reduced. 
     In the tenth configuration, the formation of the first opening and the second opening and the formation of the third opening may be executed in the same process (Eleventh configuration). 
     According to the eleventh configuration described above, the number of processes can be reduced. 
     In any one of the ninth to eleventh configurations, the formation of the pixel electrode may be forming the pixel electrode in the recessed portion as well as in an upper layer of the second insulating layer, between the recessed portion and the touch sensor line, in plan view (Twelfth configuration). 
     According to the twelfth configuration described above, the area of the pixel electrode can be made larger compared to a case in which the pixel electrode is formed only in the recessed portion. Further, similar to the eighth configuration described above, the light transmittance of the display panel (liquid crystal layer) can be further improved. 
     While preferred embodiments of the disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the disclosure. The scope of the disclosure, therefore, is to be determined solely by the following claims.