JP2014035434A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device that suppresses deterioration in display quality.SOLUTION: A liquid crystal display device comprises a first substrate 110, a second substrate 120 that is disposed to face the first substrate 110, and a liquid crystal layer 70 held between the first substrate 110 and the second substrate 120. The first substrate 110 comprises a sensor including a first sensor S1 having sensor blocks B1 arranged in a first direction and electrically connected to each other and a second sensor S2 extending in a second direction, which intersects with the first direction, between the sensor blocks B1; a scan line 11 extending in the first direction and disposed below the sensor with an insulation layer interposed therebetween; a signal line 12 extending in the second direction; and a pixel electrode 60 disposed to face the sensor block B1 or the second sensor S2 in a region surrounded by the scan line 11 and the signal line 12. The width WA of the scan line 11 in a region facing the sensor block B1 is different from the width WB of the scan line 11 in a region facing the second sensor S2.

Description

  Embodiments described herein relate generally to a liquid crystal display device.

  In recent years, flat display devices have been actively developed, and among them, liquid crystal display devices have been applied to various fields by taking advantage of features such as light weight, thinness, and low power consumption. Such a liquid crystal display device has a configuration in which a liquid crystal layer is held between a pair of substrates, and displays an image by controlling a modulation rate for light passing through the liquid crystal layer by an electric field between a pixel electrode and a common electrode. Is.

  The liquid crystal display device includes a method in which a vertical electric field in a direction substantially orthogonal to the substrate surfaces of a pair of substrates is applied to the liquid crystal layer to control the alignment state of the liquid crystal, and a horizontal electric field in a direction substantially parallel to the substrate surfaces of the pair of substrates. A method of controlling the alignment state of the liquid crystal by applying (including a fringe electric field) to the liquid crystal layer is known.

  A liquid crystal display device using a lateral electric field has attracted particular attention from the viewpoint of wide viewing angle. A horizontal electric field type liquid crystal display device such as an in-plane switching (IPS) mode or a fringe field switching (FFS) mode includes a pixel electrode and a common electrode formed on an array substrate, and is arranged with respect to the main surface of the array substrate. The liquid crystal molecules are switched by a substantially parallel lateral electric field.

  There has also been proposed a liquid crystal display device having a contact sensor that detects that a user's finger or pen tip has touched the display unit. The contact sensor may be formed by further overlapping a sensor substrate having a sensor electrode on the display portion of the liquid crystal display device, or the sensor electrode may be integrally formed on one of the pair of substrates of the liquid crystal display device.

JP 2010-231773 A

  When the sensor electrode is integrally formed on one of the pair of substrates, luminance unevenness occurs along the region where the sensor electrode is disposed, and the display quality may be lowered.

  Embodiments of the present invention have been made in view of the above circumstances, and an object thereof is to provide a liquid crystal display device that suppresses deterioration in display quality.

  According to the embodiment, a first sensor including sensor blocks arranged side by side in the first direction and electrically connected to each other, and a second sensor extending in a second direction intersecting the first direction between the block electrodes, A sensor including a scanning line disposed in a lower layer of the sensor via an insulating layer extending in the first direction, a signal line extending in the second direction, and the scanning line and the signal line. A first substrate including a pixel electrode disposed to face the sensor block and the second sensor in a region, a second substrate disposed to face the first substrate, and the first substrate A liquid crystal layer held between the substrate and the second substrate, and a width of the scanning line in a region facing the sensor block, and a width of the scanning line in a region facing the second sensor, Is different LCD display Location is provided.

FIG. 1 is a perspective view for explaining a configuration example of the liquid crystal display device of the embodiment. 2 is a diagram showing an example of a cross section taken along line II-II of the liquid crystal display device shown in FIG. FIG. 3 is a diagram for explaining an example of the configuration of the common electrode in the display area of the array substrate. FIG. 4 is a diagram schematically showing an example of a cross section of the array substrate taken along line IV-IV in FIG. FIG. 5 is a diagram schematically illustrating a configuration example of a display pixel of the liquid crystal display device according to the embodiment. FIG. 6 is a diagram schematically illustrating a configuration example of a display pixel of the liquid crystal display device according to the embodiment.

Hereinafter, a liquid crystal display device according to an embodiment will be described with reference to the drawings.
FIG. 1 schematically shows an example of the liquid crystal display device of the present embodiment. The liquid crystal display device includes an array substrate 110, a counter substrate 120 disposed opposite to the array substrate 110 with a predetermined gap, and a liquid crystal layer 70 sandwiched between the array substrate 110 and the counter substrate 120 (shown in FIG. 2). ) And a display area 25 including display pixels PX arranged in a matrix, and a backlight unit 130 that illuminates the liquid crystal display panel from the back side.

  In the display area 25, the scanning lines 11 extending along the rows in which the display pixels PX are arranged, the signal lines 12 extending along the columns, and the positions near the positions where the scanning lines 11 and the signal lines 12 intersect are arranged. The switching element 14, the pixel electrode 60 disposed in each display pixel PX, and the common electrode 30 facing the pixel electrode 60 through the liquid crystal layer 70 are disposed.

  Around the display area 25 of the liquid crystal display panel, a scanning line driving circuit YD and a signal line driving circuit XD are arranged. The scanning line driving circuit YD is disposed at a position sandwiching the display area 25 in the row direction.

  The scanning line driving circuit YD is disposed on both sides of the display area 25 in the direction in which the scanning line 11 extends, and a plurality of scanning lines 11 extending from the display area 25 are electrically connected to the scanning line driving circuit YD. A plurality of signal lines 12 extending from the display area 25 are electrically connected to the signal line driving circuit XD.

  A flexible substrate (not shown) is connected to the end of the array substrate 110, and a control signal, a video signal, and the like are supplied to the scanning line drive circuit YD and the signal line drive circuit XD from an external signal source (not shown) via the flexible substrate. The

  FIG. 2 is a diagram showing an example of a cross section taken along II-II of the liquid crystal display panel shown in FIG. The liquid crystal display device of the present embodiment is an FFS mode liquid crystal display device that controls the alignment state of a liquid crystal layer using a lateral electric field.

  The array substrate 110 includes a transparent insulating substrate 10 such as glass, a pixel driving wiring disposed on the transparent insulating substrate 10, a switching element 14, insulating films L1 and 50, a planarizing film 20, and a common electrode. 30, a sensor electrode 40, a pixel electrode 60, an alignment film (not shown), and a driving circuit including a scanning line driving circuit and a signal line driving circuit. The pixel drive wiring includes a scanning line 11 extending along a row where a plurality of display pixels PX are arranged, and a signal line 12 extending along a column where the plurality of display pixels PX are arranged.

  The switching element 14 is disposed in the vicinity of the position where the scanning line 11 and the signal line 12 intersect. The switching element 14 is disposed on an undercoat layer (not shown) disposed on the transparent insulating substrate 10, and includes an amorphous silicon or polysilicon semiconductor layer SC, a gate electrode 14b, a source electrode 14a, and a drain electrode 14c. , Including a thin film transistor.

  A gate insulating film is disposed above the semiconductor layer SC of the switching element 14, and a gate electrode 14b of the switching element 14 is disposed on the gate insulating film. The source electrode 14a and the drain electrode 14c of the switching element 14 are connected to the semiconductor layer SC through a contact hole provided in the insulating film L1.

  The gate electrode 14b of the switching element 14 is electrically connected to the corresponding scanning line 11 (or formed integrally). The source electrode 14a of the switching element 14 is electrically connected to the corresponding signal line 12 (or formed integrally). The drain electrode 14 c of the switching element is electrically connected to the corresponding pixel electrode 60 in the contact holes 21 and 51.

  When the scanning line 11 is driven by the scanning line driving circuit YD and a voltage is applied to the gate electrode 14b of the switching element 14, the source electrode 14a and the drain electrode 14c are electrically connected, and the switching element 14 is in an on state for a certain period. It becomes. A video signal is supplied from the signal line 12 to the pixel electrode 60 via the switching element 14 during a period in which the switching element 14 is in the on state.

  A planarizing film 20 is disposed on the switching element 14. In the present embodiment, the planarizing film 20 is a transparent organic insulating film, and the thickness of the planarizing film 20 is approximately 3 μm. The planarizing film 20 is arranged over the entire display area 25 except for the contact holes 21. The planarizing film 20 on the drain electrode 14c of the switching element 14 is provided with a contact hole 21 for electrical connection with a pixel electrode 60 described later. A common electrode 30 and a sensor electrode 40 are disposed on the planarizing film 20. The configurations of the common electrode 30 and the sensor electrode will be described in detail later.

  The common electrode 30 is an oxide conductive film formed of a transparent conductive material such as ITO (indium tin oxide) or IZO (indium zinc oxide). The common electrode 30 disposed at the end of the display region 25 is disposed so as to extend to the frame region, and a common voltage is applied from an external signal source through a flexible substrate, for example.

  The sensor electrode 40 is a multilayer electrode of aluminum and molybdenum, for example. In the present embodiment, the sensor electrode 40 is formed by laminating molybdenum, aluminum, and molybdenum in this order. The sensor electrodes 40 are arranged in a grid on the common electrode 30 as will be described later.

  The pixel electrode 60 is disposed so as to face the common electrode 30 with the insulating film 50 interposed therebetween in each display pixel PX. The pixel electrode 60 is formed of a transparent conductive material such as ITO (indium tin oxide) or IZO (indium zinc oxide).

  The counter substrate 120 includes a transparent insulating substrate 28 such as glass, a transparent resin planarizing film 29, a plurality of colored layers, and an alignment film (not shown).

  The plurality of colored layers are organic insulating films, for example, a first colored layer 24a, a second colored layer 24b, a second colored layer 24b colored by any one of resists of red (R), green (G), and blue (B). 3 colored layers 24c, a black fourth colored layer 27a, and a fifth colored layer 27b.

  The first colored layer 24a is disposed in the first color pixel PX1, the second colored layer 24b is disposed in the second color pixel PX2, and the third colored layer 24c is disposed in the third color pixel PX3. The fourth colored layer 27a is a light shielding layer that is disposed so as to surround the display region 25 and prevents light from being lost in the frame region. The fifth colored layer 27b is a light shielding layer that is arranged in a grid pattern at positions facing the scanning lines 11 and the signal lines 12 of the array substrate 110, and prevents light leakage between the display pixels PX.

  For example, one picture element is composed of three types of color pixels, that is, a red display pixel, a green display pixel, and a blue display pixel. In the display area 25, red display pixels, green display pixels, and blue display pixels are periodically arranged in the direction in which the scanning lines 11 extend, and the same type of color pixels are provided in the direction in which the signal lines 12 extend. They are arranged side by side.

  The array substrate 110 and the counter substrate 120 are arranged so that their alignment films face each other, and are fixed by the sealant 26. The surface of the alignment film is subjected to an alignment process so as to define the initial alignment state of the liquid crystal molecules contained in the liquid crystal layer 70.

  A columnar spacer 22 is disposed between the array substrate 110 and the counter substrate 120. The columnar spacer 22 keeps the distance between the array substrate 110 and the counter substrate 120 constant. In the present embodiment, the height of the columnar spacer 22 is arbitrarily controlled between 2 μm and 6 μm.

  The sealing agent 26 is disposed so as to surround the display area 25. The liquid crystal layer 70 is disposed in a region surrounded by the array substrate 110, the counter substrate 120, and the sealant 26.

  Polarizing plates (not shown) are disposed on the surfaces of the array substrate 110 and the counter substrate 120 opposite to the liquid crystal layer 70 side.

  FIG. 3 is a diagram for explaining a configuration example of the sensor in the display area 25 of the array substrate 110.

  In the liquid crystal display device of the present embodiment, the sensor includes a first sensor S1 including a sensor block B1 arranged in a row direction (first direction) and a column direction (second direction), and a sensor block B1 arranged in the row direction. And a second sensor S2 extending in the column direction (second direction). Each first sensor S1 is configured by electrically connecting a plurality of sensor blocks B1 arranged side by side in the row direction.

FIG. 3 shows an enlarged boundary portion between the sensor block B1 and the second sensor S2.
Each sensor block B1 and the second sensor S2 are formed using the common electrode 30 and the sensor electrode 40.

  The common electrode 30 is disposed so as to face the plurality of pixel electrodes 60, and has an opening 30 </ b> A provided in a region where the pixel electrode 60 and the switching element 14 are in contact with each other.

  The sensor electrode 40 is disposed on the plurality of common electrodes 30 in each of the sensor block B1 and the second sensor S2. The sensor electrodes 40 are arranged in a grid surrounding the periphery of the pixel electrodes 60 arranged in a matrix.

  An end portion of the sensor electrode 40 is disposed so as to extend from the display region 25 to a frame region surrounding the display region 25, and is electrically connected to, for example, a sensing circuit (not shown) provided outside. When the touch position is detected by the liquid crystal display device of the present embodiment, the sensing circuit supplies a signal having a predetermined waveform to the sensor electrode 40. The magnitude of the capacitance generated between the fingertip and the first sensor S1 and the second sensor S2 changes according to the distance between the user's fingertip and the pen tip and the first sensor S1 and the second sensor S2. The sensing circuit detects a change in potential of the first sensor S1 and the second sensor S2 due to a change in capacitance between the fingertip or the like and the sensor from the output waveform of the signal output from the sensor electrode 40, and detects the fingertip of the user And the coordinate positions of the first sensor S1 and the second sensor S2 corresponding to the position where the pen tip or the like touches are detected.

  FIG. 4 is a diagram schematically showing an example of a cross section of array substrate 110 taken along line IV-IV in FIG. Here, an example of a cross section of the region where the second sensor S2 is arranged and the sensor block B1 arranged on both sides of the second sensor S2 in the row direction is shown. 4 that are the same as those described in FIG. 2 are denoted by the same reference numerals and description thereof is omitted.

  The first sensor S1 is configured by electrically connecting sensor blocks B1 arranged in the row direction to each other. As shown in FIG. 4, a connection electrode EJ that electrically connects the sensor blocks B1 is disposed below the second sensor S2. The sensor block B1 is electrically connected to the contact electrode EC in the contact hole 22 provided in the planarizing film 20. The contact electrode EC is electrically connected to the connection electrode EJ in the contact hole L1H provided in the insulating film L1. That is, the sensor blocks B1 arranged in the row direction are electrically connected to each other via the contact electrode EC and the connection electrode EJ.

  FIG. 5 and FIG. 6 are diagrams schematically illustrating a configuration example of the display pixel PX in the liquid crystal display device of the present embodiment. FIG. 5 shows a configuration example of the display pixel PX in the region where the sensor block B1 of the first sensor S1 is arranged, and FIG. 6 shows a configuration of the display pixel PX in the region where the second sensor S2 is arranged. An example is shown.

  The pixel electrode 60 is disposed in a region surrounded by the scanning line 11 and the signal line 12. The pixel electrode 60 includes a slit SL extending in the column direction. A plurality of slits SL are provided side by side in the row direction. In the liquid crystal display device of this embodiment, the slit SL is provided in the pixel electrode 60 as described above, so that an electric field substantially parallel to the substrate surface is generated in the liquid crystal layer 70 according to the potential difference between the pixel electrode 60 and the common electrode 30. Thus, the alignment state of the liquid crystal molecules contained in the liquid crystal layer 70 is controlled.

  In the present embodiment, the width of the scanning line 11 in the column direction is different between the region where the sensor block B1 is disposed and the region where the second sensor S2 is disposed.

  That is, the width WA of the scanning line 11 facing the sensor block B1 shown in FIG. 5 is smaller than the width WB of the scanning line 11 facing the second sensor S2 shown in FIG. In this embodiment, the width WB is approximately five times the width WA, and for example, the width WA is 2 μm and the width WB is 10 μm.

  Here, in the present embodiment, the number of pixels arranged in the region where the plurality of sensor blocks B1 arranged in the row direction is arranged and the sum of the number of pixels arranged in the row direction in the plurality of regions where the second sensor S2 is arranged. Is different. That is, when the number of pixels arranged in the row direction in the region where each sensor block B1 is arranged is P1, and the sensor block B1 is arranged in the row direction, the region where a plurality of sensor blocks B1 arranged in the row direction are arranged. The number of pixels arranged in is P1 × A. When the number of pixels arranged in the row direction is P2 in the region in which each second sensor S2 is arranged, and B second sensors S2 are arranged in the row direction, rows are arranged in a plurality of regions in which the second sensor S2 is arranged. The sum of the number of pixels arranged in the direction is P2 × B. At this time, in this embodiment, P1 × A and P2 × B are different.

  Therefore, when the width WA and the width WB of the scanning lines 11 are the same, the capacitance generated between each scanning line 11 and the common electrode 30 in the region where the sensor block B1 is disposed, and each scanning line 11 and the second width WB. The capacitance generated between the sensor S2 and the common electrode 30 in the region where the sensor S2 is disposed has a different size.

That is, the capacitance generated between the scanning line 11 and the common electrode 30 can be calculated by the following equation (1).
C = εo * S / d Formula (1)
Here, εo is a dielectric constant of the planarizing film 20 and the insulating film L1 disposed between the scanning line 11 and the common electrode 30, and S is an area where the scanning line 11 and the common electrode 30 face each other. d is the distance between the scanning line 11 and the common electrode 30. That is, the capacitance generated between the scanning line 11 and the common electrode 30 is proportional to the dielectric constant εo and the area S, and inversely proportional to the distance d.

  When P1 × A is different from P2 × B, and the width of the scanning line 11 is the same, the area S where the scanning line 11 and the common electrode 30 face each other is a value proportional to the number of pixels, and the dielectric constant εo If the distance d is the same, the capacitance generated between the scanning line 11 and the common electrode 30 is different. As a result, the amount of change in the potential of the common electrode 30 due to the signal applied to the scanning line 11 is different in the area where the sensor block B1 is arranged and the area where the second sensor S2 is arranged, and the first sensor S1. In addition, luminance unevenness may occur along the portion where the second sensor S2 is disposed.

  For example, the number of pixels arranged in the region where the plurality of sensor blocks B1 arranged in the row direction is 420 pixels (420 × 3 pixels), and the pixels arranged in the row direction in the plurality of regions where the second sensor S2 is arranged. When the sum of the numbers is 18 picture elements (18 × 3 pixels), and the width WA and width WB of the scanning line 11 are the same, the scanning line 11 and the common electrode 30 in the region where the sensor block B1 is arranged The capacity generated between the scanning lines 11 and the common electrode 30 (hereinafter referred to as the capacity C2) in the region where the second sensor S2 is disposed is approximately 23 times as large as the capacity generated during the time (hereinafter referred to as the capacity C1). It becomes.

  On the other hand, in this embodiment, since the width WA of the scanning line 11 is smaller than the width WB, the difference between the area S where the scanning line 11 and the common electrode 30 face each other is reduced, so that the capacitance C1 is reduced. The difference from the capacity C2 can be reduced. As a result, it is possible to suppress the occurrence of luminance unevenness along the portion where the first sensor S1 and the second sensor S2 are arranged.

  That is, according to the present embodiment, it is possible to provide a liquid crystal display device that suppresses deterioration in display quality.

  The widths WA and WB of the scanning lines 11 are desirably selected within a range that prevents the scanning lines 11 from being disconnected and does not decrease the aperture ratio of the display pixels PX. For example, the widths WA and WB of the scanning lines 11 are preferably 2 μm or more and 10 μm or less.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  PX ... display pixel, L1, 50 ... insulating film, S1 ... first sensor, B1 ... sensor block, S2 ... second sensor, 10 ... transparent insulating substrate, 11 ... scan line, 12 ... signal line, 14 ... switching element , 20 ... flattening film, 21 ... contact hole, 22 ... columnar spacer, 25 ... display area, 26 ... sealing agent, 28 ... transparent insulating substrate, 30 ... common electrode, 40 ... sensor electrode, 50 ... insulating film, 51 DESCRIPTION OF SYMBOLS ... Contact hole, 60 ... Pixel electrode, SL ... Slit, 70 ... Liquid crystal layer, 110 ... Array substrate, 120 ... Counter substrate, 130 ... Backlight unit.

Claims (5)

A sensor including a first sensor including sensor blocks arranged side by side in a first direction and electrically connected to each other, and a second sensor extending in a second direction intersecting the first direction between the sensor blocks; The sensor block in a region surrounded by the scanning line and the signal line extending in the first direction and disposed below the sensor via the insulating layer, the signal line extending in the second direction, and the scanning line and the signal line Or a first substrate provided with a pixel electrode disposed to face the second sensor;
A second substrate disposed opposite the first substrate;
A liquid crystal layer held between the first substrate and the second substrate,
A liquid crystal display device, wherein a width of the scanning line facing the sensor block is different from a width of the scanning line facing the second sensor.   2. The liquid crystal display device according to claim 1, wherein the sensor blocks arranged in the first direction with the second sensor interposed therebetween are electrically connected to each other through a connection electrode disposed in a lower layer of the second sensor. .   The said sensor block and the said 2nd sensor are provided with the common electrode facing the said several pixel electrode, and the sensor electrode arrange | positioned on the said some common electrode at the grid form. Liquid crystal display device.   4. The liquid crystal display device according to claim 1, wherein a width of the scanning line facing the sensor block is smaller than a width of the scanning line facing the second sensor. 5.   The liquid crystal display device according to claim 1, wherein the pixel electrode includes a slit extending in the second direction.

Images