Liquid crystal display device

Abstract

In a VA mode liquid crystal display device in which discharge wiring is arranged so as to at least partially overlap the slit formed in the pixel electrode, the reduction in contrast ratio is suppressed. [Solution] The liquid crystal display device comprises first and second substrates and a vertically aligned liquid crystal layer. The first substrate has gate wiring, source wiring, and pixel electrodes. Each pixel includes first and second sub-pixels, and the pixel electrodes include first and second sub-pixel electrodes. The first substrate has a first TFT connected to the first sub-pixel electrode, a second TFT connected to the second sub-pixel electrode, a third TFT connected to the second TFT and the second sub-pixel electrode, and discharge wiring connected to the third TFT. The pixel electrodes have slits that at least partially overlap the discharge wiring in a plan view, and the first or second substrate has a light-shielding layer including a light-shielding portion that is positioned to at least partially overlap the slits in a plan view.

Description

Technical Field

[0001] The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having a vertically aligned liquid crystal layer.

Background Art

[0002] As a method for improving the viewing angle characteristics of a liquid crystal display device in the VA (Vertical Alignment) mode, an alignment division structure in which a plurality of liquid crystal domains are formed in one pixel is known. In recent years, a 4D-RTN (Reverse Twisted Nematic) mode has been proposed as a method for forming the alignment division structure.

[0003] In the 4D-RTN mode, an alignment division structure is formed by defining the pretilt direction of liquid crystal molecules with an alignment film. A liquid crystal display device in the 4D-RTN mode is disclosed in, for example, Patent Document 1. In the liquid crystal display device disclosed in Patent Document 1, a four-divided alignment structure is formed by defining the pretilt direction with an alignment film. That is, when a voltage is applied to the liquid crystal layer, four liquid crystal domains are formed in one pixel. Such a four-divided alignment structure may be simply referred to as a 4D structure.

[0004] Also, in the 4D-RTN mode, the pretilt direction defined by one of a pair of opposing alignment films through the liquid crystal layer is substantially different by 90° from the pretilt direction defined by the other alignment film. Therefore, when a voltage is applied, the liquid crystal molecules take a twisted alignment. As understood from the disclosure of Patent Document 1, in the 4D-RTN mode, typically, four liquid crystal domains are arranged in two rows and two columns within a pixel.

[0005] In 4D-RTN mode liquid crystal display devices, as described in Patent Document 1, dark lines (areas darker than other areas) occur within pixels when voltage is applied. These dark lines cause a decrease in transmittance (a decrease in light utilization efficiency). The overall shape of the area where dark lines occur differs depending on the orientation division pattern, but regardless of the pattern adopted, it includes a cross-shaped portion corresponding to the boundary between liquid crystal domains (hereinafter also referred to as "domain boundary"). Patent Document 2 proposes forming a slit in the region of the pixel electrode located near the domain boundary in order to suppress the decrease in transmittance caused by dark lines.

[0006] Furthermore, in recent years, "pixel-splitting drive technology" has been put into practical use as a technique to improve the viewing angle characteristics of VA mode liquid crystal display devices. Pixel-splitting drive technology improves the problem that the gamma (γ) characteristics observed from the front differ from those observed from an oblique direction; in other words, it improves the viewing angle dependence of the γ characteristics. The γ characteristics are the gradation dependence of the display brightness.

[0007] In pixel-splitting drive technology, a single pixel is composed of multiple sub-pixels to which different voltages can be applied to the liquid crystal layer, that is, to which different brightness levels can be exhibited, thereby achieving a predetermined brightness corresponding to the display signal voltage input to the pixel across the entire pixel. In other words, pixel-splitting drive technology is a technique that improves the viewing angle dependence of the γ characteristics of a pixel by combining the different γ characteristics of multiple sub-pixels.

[0008] Several methods are known for pixel segmentation driving technology. One of them is the method disclosed in Patent Document 3. In this specification, the pixel segmentation driving technology method disclosed in Patent Document 3 will be referred to as the "discharge method".

[0009] Figure 22 shows the equivalent circuit of pixel P when a discharge method is adopted. Note that auxiliary capacitors are omitted in Figure 22 for simplicity of explanation. As shown in Figure 22, pixel P includes a first sub-pixel Sp1 and a second sub-pixel Sp2.

[0010] The first sub-pixel Sp1 is provided with a first liquid crystal capacitor Clc1 including the first sub-pixel electrode and a first TFTtr1. The gate electrode of the first TFTtr1 is electrically connected to the gate wiring GL and is supplied with a gate signal from the gate wiring GL. The source electrode of the first TFTtr1 is electrically connected to the source wiring SL and is supplied with a source signal from the source wiring SL. The drain electrode of the first TFTtr1 is electrically connected to the first sub-pixel electrode.

[0011] The second sub-pixel Sp2 is provided with a second liquid crystal capacitor Clc2 including a second sub-pixel electrode, and a second TFTtr2 and a third TFTtr3. The gate electrode of the second TFTtr2 is electrically connected to the gate wiring GL and supplied with a gate signal from the gate wiring GL. The source electrode of the second TFTtr2 is electrically connected to the source wiring SL and supplied with a source signal from the source wiring SL. The drain electrode of the second TFTtr2 is electrically connected to the second sub-pixel electrode. The gate electrode of the third TFTtr3 is electrically connected to the gate wiring GL and supplied with a gate signal from the gate wiring GL. The source electrode of the third TFTtr3 is electrically connected to the drain electrode and the second sub-pixel electrode of the second TFTtr2. The drain electrode of the third TFTtr3 is electrically connected to the discharge wiring (referred to as "reference voltage wiring" in Patent Document 3) DcL.

[0012] When the gate signal supplied by the gate wiring GL changes from a low level to a high level, the first TFTtr1, second TFTtr2, and third TFTtr3 turn on. As a result, the source signal from the source wiring SL is supplied to the first and second sub-pixel electrodes via the first TFTtr1 and second TFTtr2, respectively, and the first and second liquid crystal capacitors Clc1 and Clc2 are charged. At this time, in the second sub-pixel Sp2, voltage division occurs according to the ratio of the on-resistance of the second TFTtr2 to the on-resistance of the third TFTtr3, so the voltage applied to the second liquid crystal capacitor Clc2 is lower than the voltage applied to the first liquid crystal capacitor Clc1. Therefore, the first sub-pixel Sp1 can function as a relatively bright sub-pixel, and the second sub-pixel Sp2 can function as a relatively dark sub-pixel. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] International Publication No. 2006 / 132369 [Patent Document 2] International Publication No. 2018 / 138888 [Patent Document 3] U.S. Patent No. 9958739 [Overview of the Initiative] [Problems that the invention aims to solve]

[0014] The inventors of this application considered adopting the configuration proposed in Patent Document 2 (a configuration in which slits are formed near the domain boundaries of the pixel electrodes) for a 4D-RTN mode liquid crystal display device, and further considering combining it with a discharge-type pixel division driving technology. As a result of this investigation, as will be described in detail later, it was found that depending on the arrangement of the discharge wiring, light leakage may occur near the slits, potentially reducing the contrast ratio.

[0015] The present invention has been made in view of the above problems, and its purpose is to suppress a decrease in contrast ratio in a VA mode liquid crystal display device in which discharge wiring is arranged so as to at least partially overlap a slit formed in a pixel electrode. [Means for solving the problem]

[0016] This specification discloses liquid crystal display devices as described in the following items.

[0017] [Item 1] A first substrate and a second substrate facing each other, A vertically aligned liquid crystal layer is provided between the first substrate and the second substrate, A liquid crystal display device having multiple pixels arranged in a matrix including multiple pixel rows and multiple pixel columns, The first substrate has gate wiring that supplies a gate signal to a corresponding pixel row among the plurality of pixel rows, source wiring that supplies a source signal to a corresponding pixel column among the plurality of pixel columns, and pixel electrodes provided for each of the plurality of pixels. The second substrate in the series has a counter electrode facing the pixel electrode, Each of the plurality of pixels includes a first sub-pixel and a second sub-pixel to which different voltages can be applied to the liquid crystal layer. The pixel electrode includes a first sub-pixel electrode provided on the first sub-pixel and a second sub-pixel electrode provided on the second sub-pixel. The aforementioned first substrate is A first TFT electrically connected to the gate wiring, the source wiring, and the first sub-pixel electrode, A second TFT electrically connected to the gate wiring, the source wiring, and the second sub-pixel electrode, The gate wiring, the second TFT and the third TFT electrically connected to the second sub-pixel electrode, Discharge wiring electrically connected to the third TFT, It has, The pixel electrode has at least one slit that at least partially overlaps the discharge wiring in a plan view. The liquid crystal display device includes a light-shielding layer including a light-shielding portion disposed so as to at least partially overlap the slit in a plan view, on the first substrate or the second substrate.

[0018] [Item 2] The liquid crystal display device according to Item 1, wherein the slit includes a portion that overlaps both the light-shielding portion and the discharge wiring in a plan view, and a portion that overlaps the light-shielding portion and does not overlap the discharge wiring in a plan view.

[0019] [Item 3] In the liquid crystal display device according to Item 1 or 2, a potential applied to the discharge wiring is different from a potential applied to the counter electrode.

[0020] [Item 4] The liquid crystal display device according to any one of Items 1 to 3, wherein the first substrate has the light-shielding layer.

[0021] [Item 5] In the liquid crystal display device according to Item 4, the light-shielding layer is formed of a conductive material and is given a predetermined potential.

[0022] [Item 6] The first substrate further has auxiliary capacitance wiring, In the liquid crystal display device according to Item 5, the predetermined potential applied to the light-shielding layer is the same as a potential applied to the auxiliary capacitance wiring.

[0023] [Item 7] The discharge wiring is formed in the same layer as the source wiring, The liquid crystal display device according to any one of Items 4 to 6, wherein the light-shielding layer is formed in the same layer as the gate wiring.

[0024] [Item 8] The first substrate further comprises a first alignment film provided between the pixel electrode and the liquid crystal layer, The second substrate further comprises a second alignment film provided between the counter electrode and the liquid crystal layer, Each of the first sub-pixel and the second sub-pixel has a plurality of liquid crystal domains whose reference orientation directions, defined by the first alignment layer and the second alignment layer, are different from each other. The plurality of liquid crystal domains include a first liquid crystal domain whose reference orientation direction is a first direction, a second liquid crystal domain whose reference orientation direction is a second direction, a third liquid crystal domain whose reference orientation direction is a third direction, and a fourth liquid crystal domain whose reference orientation direction is a fourth direction. The at least one slit is at least one first slit extending substantially parallel to the first direction, and includes at least one first slit located near a first boundary which is the boundary between the first liquid crystal domain and other liquid crystal domains. The liquid crystal display device according to any one of items 1 to 7, wherein the discharge wiring is arranged to overlap the first boundary in a plan view.

[0025] [Item 9] The light-shielding layer extends in substantially the same direction as the discharge wiring extends. The discharge wiring comprises a first wiring edge and a second wiring edge that define the width of the discharge wiring, the first wiring edge being located relatively to the first liquid crystal domain side and the second wiring edge being located relatively to the other liquid crystal domain side. The light-shielding portion comprises a first light-shielding layer edge and a second light-shielding layer edge that define the width of the light-shielding portion, the first light-shielding layer edge located relatively on the side of the first liquid crystal domain and the second light-shielding layer edge located relatively on the side of the other liquid crystal domain. The liquid crystal display device according to item 8, wherein the first wiring edge is located between the first boundary and the first light-shielding layer edge.

[0026] [Item 10] The liquid crystal display device according to item 9, wherein the light-shielding portion is positioned such that, in a plan view, the widthwise center of the light-shielding portion is shifted toward the first wiring edge side than the widthwise center of the discharge wiring.

[0027] [Item 11] The liquid crystal display device according to item 9 or 10, wherein the distance from the first wiring edge to the first light-shielding layer edge in a plan view is 1.4 μm or more.

[0028] [Item 12] The liquid crystal display device according to any one of items 9 to 11, wherein the distance from the first wiring edge to the first light-shielding layer edge in a plan view is 4.0 μm or less.

[0029] [Item 13] The liquid crystal display device according to any one of items 8 to 12, wherein the at least one first slit includes a first long slit and at least one first short slit shorter than the first long slit.

[0030] [Item 14] Each of the at least one first short slits is such that, in a plan view, its entirety overlaps the light-shielding portion. The liquid crystal display device according to item 13, wherein the first long slit includes a portion that overlaps with the light-shielding portion and a portion that does not overlap with the light-shielding portion in a plan view.

[0031] [Item 15] The first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are arranged in a 2x2 grid, The first liquid crystal domain and the second liquid crystal domain are adjacent to each other in an oblique direction that is inclined with respect to the row and column directions. The pixel electrode has at least one second slit formed in a region corresponding to the second liquid crystal domain and extending substantially parallel to the second direction, and having at least one second slit located near a second boundary which is the boundary between the second liquid crystal domain and other liquid crystal domains. The discharge wiring is arranged so as to overlap with the second boundary in a plan view. The liquid crystal display device according to any one of items 8 to 14, wherein the light-shielding layer includes further light-shielding portions arranged to at least partially overlap the plurality of second slits in a plan view.

[0032] [Item 16] The third liquid crystal domain is adjacent to the first liquid crystal domain in the row direction and adjacent to the second liquid crystal domain in the column direction. The fourth liquid crystal domain is adjacent to the first liquid crystal domain in the column direction and adjacent to the second liquid crystal domain in the row direction. The first boundary is the boundary between the first liquid crystal domain and the third liquid crystal domain, The liquid crystal display device according to item 15, wherein the second boundary is the boundary between the second liquid crystal domain and the fourth liquid crystal domain.

[0033] [Item 17] The liquid crystal display device according to any one of items 8 to 16, wherein the first direction, the second direction, the third direction and the fourth direction are four directions in which the difference between any two directions is approximately equal to an integer multiple of 90°.

[0034] [Item 18] A liquid crystal display device according to any one of items 8 to 17, wherein the first direction and the second direction form an angle of approximately 180°.

[0035] [Item 19] A liquid crystal display device according to any one of items 8 to 18, wherein each of the first alignment film and the second alignment film is a photoalignment film. [Effects of the Invention]

[0036] According to an embodiment of the present invention, in a VA mode liquid crystal display device in which discharge wiring is arranged to at least partially overlap a slit formed in a pixel electrode, a decrease in the contrast ratio can be suppressed. [Brief explanation of the drawing]

[0037] [Figure 1] This figure shows the orientation division structure of 900P pixels in a typical 4D-RTN mode liquid crystal display device. [Figure 2A] This figure illustrates a method for obtaining an orientation division structure for 900P pixels, showing the pre-tilt directions PD1 and PD2 defined by the orientation film provided on the active matrix substrate. [Figure 2B] This figure illustrates a method for obtaining an orientation division structure for 900P pixels, showing the pre-tilt directions PD3 and PD4 defined by the orientation film provided on the opposing substrate. [Figure 2C] This diagram illustrates a method for obtaining a pixel 900P alignment division structure, showing the tilt direction (director) when a voltage is applied to the liquid crystal layer after bonding the active matrix substrate and the opposing substrate. [Figure 3] This diagram schematically shows the orientation state of liquid crystal molecules 931 in pixel 900P. [Figure 4] This is a plan view showing the orientation state of liquid crystal molecules 931 near the edge SD1 of the pixel electrode 911. [Figure 5A] This is a schematic cross-sectional view of a liquid crystal display device 100 according to an embodiment of the present invention, showing a cross-section along the line 5A-5A' in Figure 8. [Figure 5B] This is a schematic cross-sectional view of the liquid crystal display device 100, showing a cross-section along the line 5B-5B' in Figure 8. [Figure 6] This figure shows the orientation division structure of pixels P in a liquid crystal display device 100. [Figure 7] This is an equivalent circuit diagram of a pixel P of a liquid crystal display device 100. [Figure 8] This is a schematic plan view of the liquid crystal display device 100, showing the area corresponding to one pixel P. [Figure 9] This is a schematic plan view showing the pixel electrodes 11 of the liquid crystal display device 100, along with the domain arrangement. [Figure 10A] This is a cross-sectional view of the comparative example liquid crystal display device 1000, showing a cross-section along the line 10A-10A' in Figure 11. [Figure 10B] This is a cross-sectional view of the liquid crystal display device 1000, showing a cross-section along the line 10B-10B' in Figure 11. [Figure 11] This is a plan view of the liquid crystal display device 1000, showing the area corresponding to one pixel P. [Figure 12] This figure shows the results of a simulation to determine the transmittance distribution within the second sub-pixel Sp2 when displaying black for the comparative example liquid crystal display device 1000. [Figure 13] This figure shows the results of orientation simulation to determine the transmittance distribution within the second sub-pixel Sp2 when displaying black in the liquid crystal display device 100. [Figure 14A] This is a schematic cross-sectional view showing another liquid crystal display device 200 according to an embodiment of the present invention, and shows a cross-section along the line 14A-14A' in Figure 15. [Figure 14B] This is a schematic cross-sectional view of the liquid crystal display device 200, showing a cross-section along the line 14B-14B' in Figure 15. [Figure 15] This is a schematic plan view of the liquid crystal display device 200, showing the area corresponding to one pixel P. [Figure 16] This figure shows the results of orientation simulation to determine the transmittance distribution within the second sub-pixel Sp2 when displaying black in the liquid crystal display device 200. [Figure 17] This diagram shows the first long slit s1A and the first short slit s1B overlapping the discharge wiring DcL. [Figure 18] This graph shows the results of checking the light leakage profiles for the first long slit s1A and the first short slit s1B. [Figure 19] This figure shows the discharge wiring DcL and the first light-shielding portion 18a of the light-shielding layer 18 overlapping the first short slit s1B. [Figure 20]This graph shows the results of calculating and verifying the black luminance, white luminance, and contrast ratio for the first short slit s1B by changing the protrusion width of the first light-shielding portion 18a from the first wiring edge Le1 of the discharge wiring DcL. [Figure 21] This figure shows the discharge wiring DcL and the second light-shielding portion 18b of the light-shielding layer 18 overlapping the second short slit s2B. [Figure 22] This figure shows the equivalent circuit of a pixel P to which a discharge-type pixel division drive technology is applied. [Modes for carrying out the invention]

[0038] First, I will explain the main terms used in this specification.

[0039] In this specification, "vertically aligned liquid crystal layer" refers to a liquid crystal layer in which liquid crystal molecules are oriented substantially perpendicular to the surface of an alignment film (vertically aligned film) (for example, at an angle of about 85° or more). The liquid crystal molecules contained in the vertically aligned liquid crystal layer have negative dielectric anisotropy. By combining the vertically aligned liquid crystal layer with a pair of polarizing plates arranged in crossed nicols so as to face each other across the liquid crystal layer (i.e., arranged so that their respective transmission axes are substantially orthogonal to each other), a normally black mode display is achieved.

[0040] Furthermore, in this specification, "pixel" refers to the smallest unit that expresses a specific grayscale in a display, and in color displays, for example, it corresponds to the units that express the respective grayscales of R, G, and B. A combination of R pixels, G pixels, and B pixels constitutes one color display pixel. In addition, in this specification, the area (pixel area) of a liquid crystal display device that corresponds to a "pixel" of a display is also called a "pixel".

[0041] The "pre-tilt direction" refers to the orientation direction of liquid crystal molecules defined by the alignment film, and indicates the azimuthal angle direction within the display surface. The angle that the liquid crystal molecules make with the surface of the alignment film is called the "pre-tilt angle." The alignment treatment of the alignment film (a treatment to give the alignment film the ability to define a pre-tilt direction in a predetermined direction) is preferably performed by photo-alignment treatment, as described later.

[0042] A four-part structure can be formed by changing the combination of pre-tilt directions of a pair of opposing alignment films separated by a liquid crystal layer. Each of the four divided pixels (pixel regions) has four liquid crystal domains.

[0043] Each liquid crystal domain is characterized by the tilt direction (sometimes called the "reference orientation direction") of the liquid crystal molecules near the center of the liquid crystal layer in the layer plane and thickness direction when a voltage is applied to the liquid crystal layer, and this tilt direction (reference orientation direction) has a dominant influence on the viewing angle dependence of each domain. The tilt direction is the direction indicated by the component of the vector (the projection onto the substrate plane) of the vector that points from the end of the tilted liquid crystal molecule closer to the substrate on the back side to the end farther away from the substrate (i.e., the end on the front side closer to the substrate) (as shown in Figure 2A later, etc., from the tip of the pin to the head), and is the azimuth direction. The reference for the azimuth direction is the horizontal direction of the display surface, and counterclockwise is considered positive (if the display surface is likened to a clock face, the 3 o'clock position is considered to be an azimuth angle of 0°, and counterclockwise is considered positive). By setting the tilt directions of the four liquid crystal domains to four directions where the angle between any two directions is approximately an integer multiple of 90° (for example, 10:30, 7:30, 4:30, and 1:30), the viewing angle characteristics are averaged, and a good display can be obtained. Furthermore, from the viewpoint of uniformity of viewing angle characteristics, it is preferable that the area occupied by the four liquid crystal domains within the pixel area is approximately equal to each other.

[0044] The vertically aligned liquid crystal layer illustrated in the following embodiment contains liquid crystal molecules with negative dielectric anisotropy (nematic liquid crystal material with negative dielectric anisotropy), and the pre-tilt direction defined by one alignment film and the pre-tilt direction defined by the other alignment film are approximately 90° apart from each other, and the tilt direction (reference alignment direction) of the liquid crystal domain is defined by these two pre-tilt directions. When a voltage is applied to the liquid crystal layer, the liquid crystal molecules near the alignment films take on a twisted orientation according to the alignment restricting force of the alignment films. A chiral agent may or may not be added to the liquid crystal layer, or it may be added as needed. In this way, by using a pair of vertical alignment films provided so that their pre-tilt directions (alignment processing directions) are orthogonal to each other, the VA mode in which the liquid crystal molecules take on a twisted orientation is sometimes called the VATN (Vertical Alignment Twisted Nematic) mode. In the VATN mode, it is preferable that the pre-tilt angles defined by each of the pair of alignment films are approximately equal to each other.

[0045] From the viewpoint of mass production, photo-alignment treatment is preferred as the orientation treatment for alignment films. Furthermore, since photo-alignment treatment can be performed without contact, there is no generation of static electricity due to friction, as in rubbing treatment, and a decrease in yield can be prevented. In addition, by using a photo-alignment film containing photosensitive groups, variations in the pre-tilt angle can be suppressed.

[0046] Next, we will explain the orientation division structure in 4D-RTN mode.

[0047] Figure 1 shows the orientation division structure of pixel 900P in a typical 4D-RTN mode liquid crystal display device. When a voltage is applied to the liquid crystal layer, four liquid crystal domains A, B, C, and D are formed in pixel 900P, as shown in Figure 1. The four liquid crystal domains A, B, C, and D are arranged in a 2x2 matrix.

[0048] The director orientations ta, tb, tc, and td of liquid crystal domains A, B, C, and D are four orientations in which the angle between any two orientations is approximately equal to an integer multiple of 90°. Directors ta, tb, tc, and td represent the orientation of the liquid crystal molecules contained within each liquid crystal domain, and in 4D-RTN mode, they are the tilt directions of the liquid crystal molecules near the center of the liquid crystal layer in the layer plane and thickness direction when a voltage is applied to the liquid crystal layer (i.e., located near the center when viewing the liquid crystal domain from the direction normal to the display plane and when viewing it in a cross-section along the direction normal to the display plane). Each liquid crystal domain is characterized by the director orientation (the tilt direction described above), and this director orientation has a dominant influence on the viewing angle dependence of each domain.

[0049] Here, a pair of polarizing plates facing each other across a liquid crystal layer are arranged so that their transmission axes (polarization axes) are orthogonal to each other. More specifically, the pair of polarizing plates are arranged such that the transmission axis of one plate is parallel to the horizontal direction of the display surface (3 o'clock and 9 o'clock directions), and the transmission axis of the other plate is parallel to the vertical direction of the display surface (12 o'clock and 6 o'clock directions).

[0050] Assuming the horizontal azimuth angle (3 o'clock direction) on the display surface is 0°, the direction of director ta in liquid crystal domain A is approximately 225°, the direction of director tb in liquid crystal domain B is approximately 315°, the direction of director tc in liquid crystal domain C is approximately 45°, and the direction of director td in liquid crystal domain D is approximately 135°. In other words, liquid crystal domains A, B, C, and D are arranged such that the direction of each director differs by approximately 90° between adjacent liquid crystal domains.

[0051] Here, with reference to Figures 2A, 2B, and 2C, the orientation division method for obtaining the pixel 900P orientation division structure shown in Figure 1 will be explained. Figure 2A shows the pre-tilt directions PD1 and PD2 defined by the alignment film provided on the active matrix substrate, and Figure 2B shows the pre-tilt directions PD3 and PD4 defined by the alignment film provided on the opposing substrate. Figure 2C shows the tilt direction (director) when a voltage is applied to the liquid crystal layer after the active matrix substrate and the opposing substrate are bonded together. Figures 2A, 2B, and 2C are views of the active matrix substrate, opposing substrate, and liquid crystal layer from the observer's perspective. Therefore, in Figure 2A, the alignment film is located on the near side of the paper relative to the substrate, and in Figure 2B, the alignment film is located on the far side of the paper relative to the substrate. Furthermore, the pre-tilt and tilt directions are schematically represented by pins, with the head of the pin (the end with the larger area) representing the front side (observer side) of the liquid crystal molecule, and the tip of the pin (the end with the smaller area) representing the back side of the liquid crystal molecule.

[0052] The active matrix substrate region (the region corresponding to one 900P pixel) is divided into two parts, left and right, as shown in Figure 2A. The alignment films (vertical alignment films) in each region (left region and right region) are oriented so that they define antiparallel pre-tilt directions PD1 and PD2. Here, the photo-alignment process is performed by obliquely irradiating ultraviolet light (e.g., linearly polarized ultraviolet light) from the direction indicated by the arrow.

[0053] On the other hand, the region on the opposing substrate side (the region corresponding to one pixel region 900P) is divided into two parts, upper and lower, as shown in Figure 2B. Alignment processing is performed so that the alignment films (vertical alignment films) of each region (upper region and lower region) define antiparallel pre-tilt directions PD3 and PD4. Here, the optical alignment processing is performed by obliquely irradiating ultraviolet light (for example, linearly polarized ultraviolet light) from the direction indicated by the arrow.

[0054] As shown in Figures 2A and 2B, by bonding an alignment-treated active matrix substrate and a counter substrate, an alignment-divided pixel 900P can be formed as shown in Figure 2C. As can be seen from Figures 2A, 2B, and 2C, for each of the liquid crystal domains A to D, the pre-tilt direction defined by the photo-alignment film on the active matrix substrate side and the pre-tilt direction defined by the photo-alignment film on the counter substrate side are approximately 90° apart from each other, and the tilt direction (reference alignment direction) is defined by these two pre-tilt directions. As can be seen from Figure 2C, the tilt direction is defined in the direction midway between the pins corresponding to the two pre-tilt directions.

[0055] Furthermore, as shown in Figure 2C, dark lines DL1 to DL8 are generated within the pixel 900P having an orientation division structure. These dark lines DL1 to DL8 include dark lines DL1 to DL4 that occur at the boundaries between adjacent liquid crystal domains and dark lines DL5 to DL8 that occur near the edge of the pixel electrode. In the example shown in Figure 2C, the dark lines DL1 to DL8 as a whole are shaped like a right swastika. The reason why such dark lines DL1 to DL8 occur will be explained below with reference to Figure 3. Figure 3 is a schematic plan view showing the orientation state of liquid crystal molecules 931 in pixel 900P.

[0056] First, let's explain why dark lines DL1 to DL4 occur.

[0057] When a voltage is applied between the pixel electrode 911 and the counter electrode, a longitudinal electric field is generated in the liquid crystal layer, and the liquid crystal molecules 931 in the liquid crystal layer orient themselves in a direction perpendicular to the electric field. In other words, the liquid crystal molecules 931 tilt so that they are parallel to the substrate surface. At this time, the orientation of the director of the liquid crystal molecules 931 in each liquid crystal domain is determined by the pre-tilt direction of the alignment film on the active matrix substrate side (shown by a dotted arrow in Figure 3) and the pre-tilt direction of the alignment film on the counter substrate side (shown by a solid arrow in Figure 3). Specifically, the orientations of the directors of liquid crystal domains A, B, C, and D are approximately 225°, approximately 315°, approximately 45°, and approximately 135°, respectively.

[0058] Near the boundaries between adjacent liquid crystal domains, the orientation direction of liquid crystal molecules 931 changes continuously (due to the liquid crystal's properties as a continuous elastic material). For example, at the boundary between liquid crystal domain A and liquid crystal domain B, liquid crystal molecules 931 are oriented approximately at 270°. Similarly, at the boundaries between liquid crystal domain B and liquid crystal domain C, between liquid crystal domain C and liquid crystal domain D, and between liquid crystal domain D and liquid crystal domain A, liquid crystal molecules 931 are oriented approximately at 0°, approximately at 90°, and approximately at 180°, respectively. Since the 0°, 90°, 180°, and 270° directions are parallel or perpendicular to the transmission axes of the pair of polarizers, dark lines DL1 to DL4 are generated at the boundaries between adjacent liquid crystal domains.

[0059] Next, I will explain the reasons why dark lines DL5~DL8 occur.

[0060] If there is a portion (hereinafter referred to as the "edge portion") at the edge of a pixel electrode 911 adjacent to a liquid crystal domain, where the azimuthal angle direction perpendicular to the edge and directed inward from the pixel electrode 911 forms an angle greater than 90° with the tilt direction (reference orientation direction) of the liquid crystal domain, then a dark line will be formed inside this edge portion, parallel to the edge portion.

[0061] As shown in Figure 3, the pixel electrode 911 has four edges SD1, SD2, SD3, and SD4. When a voltage is applied to these edges SD1, SD2, SD3, and SD4, the resulting oblique electric field exerts an orientation-regulating force that is perpendicular to each edge and has a component in the direction toward the inside of the pixel electrode 911 (azimuth direction). In Figure 3, the azimuth directions perpendicular to the four edges SD1, SD2, SD3, and SD4 and toward the inside of the pixel electrode 911 are indicated by arrows e1, e2, e3, and e4.

[0062] Each of the four liquid crystal domains A, B, C, and D is adjacent to two of the four edges SD1, SD2, SD3, and SD4 of the pixel electrode 911, and when a voltage is applied, it is subjected to an orientation restricting force by the oblique electric field generated at each edge.

[0063] At the edge portion EG1 (the upper half of the left edge SD1) of the pixel electrode 911 adjacent to liquid crystal domain A, the azimuthal angle direction e1 perpendicular to the edge portion EG1 and directed inward towards the pixel electrode 911 forms an angle greater than 90° (specifically, approximately 135°) with the tilt direction ta of liquid crystal domain A. As a result, when voltage is applied, a dark line DL5 is generated in liquid crystal domain A parallel to this edge portion EG1.

[0064] Similarly, at the edge portion EG2 (the left half of the lower edge SD2) of the pixel electrode 911 adjacent to liquid crystal domain B, the azimuthal angle direction e2, which is perpendicular to the edge portion EG2 and points inward towards the pixel electrode 911, forms an angle greater than 90° (specifically, approximately 135°) with the tilt direction tb of liquid crystal domain B. As a result, when voltage is applied, a dark line DL6 is generated in liquid crystal domain B parallel to this edge portion EG2.

[0065] Similarly, at the edge portion EG3 (the lower half of the right edge SD3) of the pixel electrode 911 adjacent to the liquid crystal domain C, the azimuthal angle direction e3, which is perpendicular to the edge portion EG3 and points inward towards the pixel electrode 911, forms an angle greater than 90° (specifically, approximately 135°) with the tilt direction tc of the liquid crystal domain C. As a result, when voltage is applied, a dark line DL7 is generated in the liquid crystal domain C parallel to this edge portion EG3.

[0066] Similarly, at the edge portion EG4 (the right half of the upper edge SD4) of the pixel electrode 911 adjacent to the liquid crystal domain D, the azimuthal angle direction e4, which is perpendicular to the edge portion EG4 and points inward towards the pixel electrode 911, forms an angle greater than 90° (specifically, approximately 135°) with the tilt direction td of the liquid crystal domain D. As a result, when voltage is applied, a dark line DL8 is generated in the liquid crystal domain D parallel to this edge portion EG4.

[0067] Figure 4 shows the orientation of liquid crystal molecules 931 near edge SD1. As shown in Figure 4, near the edge portion EG1 of edge SD1, the orientation changes continuously from a direction perpendicular to edge SD1 (approximately 0° direction) to the tilt direction ta of liquid crystal domain A (approximately 225° direction). As a result, there is a region in which liquid crystal molecules 931 are oriented in a direction approximately parallel or approximately perpendicular to the transmission axes PA1 and PA2 of the pair of polarizers (approximately 270° direction). This region becomes the dark line DL5.

[0068] In contrast, in the vicinity of the portion of edge SD1 other than the edge portion EG1, the orientation changes continuously from a direction perpendicular to edge SD1 (approximately 0° direction) to the tilt direction tb of liquid crystal domain B (approximately 315° direction), but there are no regions in which the liquid crystal molecules 931 are oriented in a direction approximately parallel or approximately perpendicular to the transmission axes PA1 and PA2 of the polarizer. Therefore, no dark lines are generated.

[0069] For the same reasons, dark lines DL6, DL7, and DL8 appear near the edges EG2, EG3, and EG4, but not near the edges EG2, EG3, and EG4.

[0070] The dark lines generated by the mechanism described above cause a decrease in the transmittance of the pixels.

[0071] Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following embodiments.

[0072] [Embodiment 1] The liquid crystal display device 100 in this embodiment will be described with reference to Figures 5A and 5B. Figures 5A and 5B are schematic cross-sectional views showing the liquid crystal display device 100, respectively.

[0073] As shown in Figures 5A and 5B, the liquid crystal display device 100 comprises a liquid crystal display panel 101 and a backlight (illumination device) 102. The liquid crystal display panel 101 has an active matrix substrate (first substrate) 10 and a counter substrate (second substrate) 20 facing each other, and a vertically aligned liquid crystal layer 30 provided between them. The backlight 102 is located on the back side of the liquid crystal display panel 101 (opposite the observer). The liquid crystal display device 100 also has a plurality of pixels arranged in a matrix, including a plurality of pixel rows and a plurality of pixel columns. Figures 5A and 5B show cross-sections corresponding to a portion of a single pixel (cross-sections along the 5A-5A' line and the 5B-5B' line in Figure 8, which will be described later).

[0074] The active matrix substrate 10 has pixel electrodes 11 provided for each of the multiple pixels, and a first alignment film 12 provided between the pixel electrodes 11 and the liquid crystal layer 30 (i.e., on the outermost surface of the active matrix substrate 10 on the liquid crystal layer 30 side). The pixel electrodes 11 and the first alignment film 12 are supported by a substrate 10a. The substrate 10a is transparent and insulating. The substrate 10a is, for example, a glass substrate or a plastic substrate. The pixel electrodes 11 are formed from a transparent conductive material (e.g., ITO). A more specific configuration of the active matrix substrate 10 will be described later.

[0075] The opposing substrate 20 has an opposing electrode 21 facing the pixel electrode 11 and a second alignment film 22 provided between the opposing electrode 21 and the liquid crystal layer 30 (i.e., on the outermost surface of the opposing substrate 20 on the liquid crystal layer 30 side). The opposing electrode 21 and the second alignment film 22 are supported by a substrate 20a. The substrate 20a is transparent and insulating. The substrate 20a is, for example, a glass substrate or a plastic substrate. The opposing electrode 21 is formed from a transparent conductive material (e.g., ITO). The opposing electrode 21 may be a continuous conductive film formed over the entire display area. That is, the opposing electrode 21 may be a common electrode that provides a common potential to all pixels.

[0076] Although not shown in the diagram, the opposing substrate 20 has a color filter layer and a black matrix in addition to the opposing electrode 21 and the second photo-alignment film 22 described above. The color filter layer typically includes a red color filter, a green color filter, and a blue color filter.

[0077] The first alignment film 12 and the second alignment film 22 have an alignment restricting force that aligns liquid crystal molecules substantially perpendicular to their surface. In this embodiment, the first alignment film 12 and the second alignment film 22 are subjected to photoalignment treatment. In other words, each of the first alignment film 12 and the second alignment film 22 is a photoalignment film.

[0078] The liquid crystal display device 100 further comprises a pair of polarizing plates 41 and 42 facing each other via a liquid crystal layer 30. The pair of polarizing plates 41 and 42 are arranged such that their respective transmission axes are substantially perpendicular to each other (i.e., crossed nicols).

[0079] Figure 6 shows the orientation division structure of a single pixel P in the liquid crystal display device 100. Figure 6 shows the row direction D1, in which the pixel rows extend, and the column direction D2, in which the pixel columns extend. In the illustrated example, the pixel P is approximately rectangular in shape, with a longitudinal direction parallel to the column direction D2 and a short direction parallel to the row direction D1.

[0080] Each pixel P of the liquid crystal display device 100 includes a first sub-pixel Sp1 and a second sub-pixel Sp2, as shown in Figure 6. Different voltages can be applied to the liquid crystal layer 30 of the first sub-pixel Sp1 and the liquid crystal layer 30 of the second sub-pixel Sp2. In other words, pixel division driving is performed in the liquid crystal display device 100. Here, a relatively high voltage can be applied to the liquid crystal layer 30 of the first sub-pixel Sp1, and a relatively low voltage can be applied to the liquid crystal layer 30 of the second sub-pixel Sp2. Therefore, the first sub-pixel Sp1 is a "bright sub-pixel" that exhibits a higher brightness than the second sub-pixel Sp2 in at least a certain grayscale, and the second sub-pixel Sp2 is a "dark sub-pixel" that exhibits a lower brightness than the first sub-pixel Sp1.

[0081] When a voltage is applied between the pixel electrode 11 and the counter electrode 21, four liquid crystal domains A, B, C, and D are formed in the liquid crystal layer 30 within the bright sub-pixel (first sub-pixel) Sp1 and the dark sub-pixel (second sub-pixel) Sp2, respectively, as shown in Figure 6. The orientations of the four directors (reference orientation directions defined by the first alignment film 12 and the second alignment film 22) ta, tb, tc, and td, which represent the orientation direction of the liquid crystal molecules contained in each of the liquid crystal domains A, B, C, and D, are different from each other.

[0082] Assuming the horizontal azimuth angle (3 o'clock direction) on the display surface is 0°, the direction of director ta of liquid crystal domain A is approximately 225°, the direction of director tb of liquid crystal domain B is approximately 315°, the direction of director tc of liquid crystal domain C is approximately 45°, and the direction of director td of liquid crystal domain D is approximately 135°. In other words, the difference between any two directions of the four directors ta, tb, tc, and td of liquid crystal domains A, B, C, and D is approximately equal to an integer multiple of 90°. In this specification, the approximately 45° direction, approximately 135° direction, approximately 225° direction, and approximately 315° direction mean "40°~50° direction," "130°~140° direction," "220°~230° direction," and "310°~320° direction," respectively.

[0083] The transmission axes (polarization axes) PA1 and PA2 of the pair of polarizers 41 and 42 are such that one is parallel to the horizontal direction of the display surface and the other is parallel to the vertical direction of the display surface. Therefore, the transmission axes PA1 and PA2 of the polarizers 41 and 42 form an angle of approximately 45° with the orientations ta, tb, tc, and td of the directors ta, tb, tc, and td of the liquid crystal domains A, B, C, and D.

[0084] In the first subpixel Sp1 and the second subpixel Sp2, the four liquid crystal domains A, B, C, and D are adjacent to each other and arranged in a 2x2 matrix. In the illustrated example, liquid crystal domains A, B, C, and D are arranged in the order of top left, bottom left, bottom right, and top right (i.e., counterclockwise from the top left). Therefore, the director orientation differs by approximately 90° between two liquid crystal domains A, B, C, and D that are adjacent in the row or column direction, and the director orientation differs by approximately 180° between two liquid crystal domains that are adjacent in an oblique direction tilted to the row and column directions. For convenience of explanation, in the following, liquid crystal domains D, B, A, and C may be referred to as the "first liquid crystal domain," "second liquid crystal domain," "third liquid crystal domain," and "fourth liquid crystal domain," respectively.

[0085] The orientation division method for obtaining the orientation division structure of pixel P shown in Figure 6 can be easily understood from the orientation division method described for the orientation division structure of pixel 900P shown in Figure 1, so its explanation is omitted here. In addition, dark lines DL1 to DL8 are generated within the first sub-pixel Sp1 and the second sub-pixel Sp2 of pixel P, respectively, for the same reasons as described for pixel 900P. Dark lines DL1 to DL8 as a whole form a right-handed swastika shape.

[0086] Here, the configuration of the liquid crystal display device 100 will be explained in more detail with reference to Figures 7, 8, and 9. Figure 7 is a diagram showing the equivalent circuit of a pixel P. Figure 8 is a schematic plan view of the liquid crystal display device 100, showing the region corresponding to one pixel P. Figure 9 is a schematic plan view of the pixel electrode 11 of the liquid crystal display device 100, also showing the domain arrangement.

[0087] As shown in Figures 7, 8, and 9, the pixel electrode 11 includes a first sub-pixel electrode 11a and a second sub-pixel electrode 11b. The first sub-pixel electrode 11a is provided on the first sub-pixel Sp1. The second sub-pixel electrode 11b is provided on the second sub-pixel Sp2.

[0088] A first liquid crystal capacitance Clc1 is formed by a first sub-pixel electrode 11a, a counter electrode 21 facing the first sub-pixel electrode 11a, and a liquid crystal layer 30 located between them. A second liquid crystal capacitance Clc2 is formed by a second sub-pixel electrode 11b, a counter electrode 21 facing the second sub-pixel electrode 11b, and a liquid crystal layer 30 located between them. A first auxiliary capacitance Ccs1 is connected electrically in parallel to the first liquid crystal capacitance Clc1. A second auxiliary capacitance Ccs2 is connected electrically in parallel to the second liquid crystal capacitance Clc2.

[0089] Each of the first sub-pixel electrode 11a and the second sub-pixel electrode 11b has at least one (here more) first slit s1, at least one (here more) second slit s2, at least one (here more) third slit s3, and at least one (here more) fourth slit s4.

[0090] The multiple first slits s1 extend approximately parallel to the director td of the liquid crystal domain D (first liquid crystal domain). Furthermore, the multiple first slits s1 are located near the first boundary BD1, which is the boundary between liquid crystal domain D and liquid crystal domain A (third liquid crystal domain). Here, the multiple first slits s1 include a first long slit s1A and at least one (multiple in the illustrated example) first short slits s1B that are shorter than the first long slit s1A. Of the multiple first slits s1, the first long slit s1A is closest to the electrode end.

[0091] The multiple second slits s2 extend approximately parallel to the director tb of liquid crystal domain B (second liquid crystal domain). Furthermore, the multiple second slits s2 are located near the second boundary BD2, which is the boundary between liquid crystal domain B and liquid crystal domain C (fourth liquid crystal domain). Here, the multiple second slits s2 include a second long slit s2A and at least one (multiple in the illustrated example) second short slits s2B that are shorter than the second long slit s2A. Of the multiple second slits s2, the second long slit s2A is closest to the electrode end.

[0092] The multiple third slits s3 extend approximately parallel to the director ta of liquid crystal domain A (third liquid crystal domain). Furthermore, the multiple third slits s3 are located near the third boundary BD3, which is the boundary between liquid crystal domain A and liquid crystal domain B (second liquid crystal domain). Here, the multiple third slits s3 include a third long slit s3A and at least one (multiple in the illustrated example) third short slits s3B that are shorter than the third long slit s3A. Of the multiple third slits s3, the third long slit s3A is closest to the electrode end.

[0093] The multiple fourth slits s4 extend approximately parallel to the director tc of liquid crystal domain C (fourth liquid crystal domain). Furthermore, the multiple fourth slits s4 are located near the fourth boundary BD4, which is the boundary between liquid crystal domain C and liquid crystal domain D (first liquid crystal domain). Here, the multiple fourth slits s4 include a fourth long slit s4A and at least one (multiple in the illustrated example) fourth short slits s4B that are shorter than the fourth long slit s4A. Of the multiple fourth slits s4, the fourth long slit s4A is closest to the electrode edge.

[0094] In the following explanation, the first slit s1, second slit s2, third slit s3, and fourth slit s4 mentioned above may be collectively referred to simply as "slits."

[0095] In addition to the pixel electrodes 11 and the first alignment film 12 described above, the active matrix substrate 10 has a plurality of gate wirings GL, a plurality of source wirings SL, a plurality of auxiliary capacitance wirings CsL, and a plurality of discharge wirings DcL.

[0096] Each gate trace GL extends in the row direction and supplies a gate signal to the corresponding pixel row among multiple pixel rows. Each source trace SL extends in the column direction and supplies a source signal to the corresponding pixel row among multiple pixel columns.

[0097] Each auxiliary capacitance wiring CsL extends in the row direction. The potential supplied to the auxiliary capacitance wiring CsL is the same as, for example, the potential supplied to the counter electrode 21 (common potential). In the illustrated example, two auxiliary capacitance wirings CsL (first auxiliary capacitance wiring CsL1 and second auxiliary capacitance wiring CsL2) are arranged in one pixel row. Each discharge wiring DcL extends in the column direction. The potential supplied to the discharge wiring DcL is a constant potential and is different from the potential supplied to the counter electrode 21.

[0098] The active matrix substrate 10 has a first TFT 13A, a second TFT 13B, and a third TFT 13C in each pixel P. Each of the first TFT 13A, second TFT 13B, and third TFT 13C has a gate electrode 13Ag, 13Bg, 13Cg, a gate insulating layer 14, a semiconductor layer (not shown), a source electrode 13As, 13Bs, 13Cs, and a drain electrode 13Ad, 13Bd, 13Cd.

[0099] The gate electrode 13Ag of the first TFT 13A is electrically connected to the gate wiring GL. In the illustrated example, a portion of the gate wiring GL (the portion overlapping the semiconductor layer of the first TFT 13A) functions as the gate electrode 13Ag. The source electrode 13As of the first TFT 13A is electrically connected to the source wiring SL. In the illustrated example, the source electrode 13As extends from the source electrode 13Bs of the second TFT 13B and is electrically connected to the source wiring SL via the source electrode 13Bs of the second TFT 13B. The drain electrode 13Ad of the first TFT 13A is electrically connected to the first sub-pixel electrode 11a. More specifically, the drain electrode 13Ad is electrically connected to the first sub-pixel electrode 11a via a first auxiliary capacitance electrode 15A formed integrally with the drain electrode 13Ad. The first auxiliary capacitance Ccs1 is formed by the first auxiliary capacitance electrode 15A, the portion of the first auxiliary capacitance wiring CsL1 that overlaps with the first auxiliary capacitance electrode 15A, and the gate insulating layer 14 located between them. In this way, the first TFT 13A is electrically connected to the gate wiring GL, the source wiring SL, and the first sub-pixel electrode 11a.

[0100] The gate electrode 13Bg of the second TFT 13B is electrically connected to the gate wiring GL. In the illustrated example, a portion of the gate wiring GL (the portion overlapping the semiconductor layer of the second TFT 13B) functions as the gate electrode 13Bg. The source electrode 13Bs of the second TFT 13B is electrically connected to the source wiring SL. In the illustrated example, the source electrode 13Bs extends from the source wiring SL. The drain electrode 13Bd of the second TFT 13B is electrically connected to the second sub-pixel electrode 11b. More specifically, the drain electrode 13Bd is electrically connected to the second sub-pixel electrode 11b via a second auxiliary capacitance electrode 15B formed integrally with the drain electrode 13Bd. The second auxiliary capacitance Ccs2 is formed by the second auxiliary capacitance electrode 15B, the portion of the second auxiliary capacitance wiring CsL2 that overlaps with the second auxiliary capacitance electrode 15B, and the gate insulating layer 14 located between them. Thus, the second TFT 13B is electrically connected to the gate wiring GL, the source wiring SL, and the second sub-pixel electrode 11b.

[0101] The gate electrode 13Cg of the third TFT 13C is electrically connected to the gate wiring GL. In the illustrated example, a portion of the gate wiring GL (the portion overlapping the semiconductor layer of the third TFT 13C) functions as the gate electrode 13Cg. The source electrode 13Cs of the third TFT 13C are electrically connected to the drain electrode 13Bd and the second sub-pixel electrode 11b of the second TFT 13B. In the illustrated example, the source electrode 13Cs extends from the second auxiliary capacitance electrode 15B and is electrically connected to the drain electrode 13Bd and the second sub-pixel electrode 11b of the second TFT 13B via the second auxiliary capacitance electrode 15B. The drain electrode 13Cd of the third TFT 13C is electrically connected to the discharge wiring DcL. In the illustrated example, a portion of the discharge wiring DcL functions as the drain electrode 13Cd of the third TFT 13C.

[0102] The first TFT 13A, the second TFT 13B, and the third TFT 13C are covered by an interlayer insulating layer 16. The pixel electrodes 11 are provided on the interlayer insulating layer 16. The interlayer insulating layer 16 has a first contact hole 16a formed on the first auxiliary capacitance electrode 15A and a second contact hole 16b formed on the second auxiliary capacitance electrode 15B. The first sub-pixel electrode 11a is electrically connected to the drain electrode 13Ad of the first TFT 13A via the first contact hole 16a. Similarly, the second sub-pixel electrode 11b is electrically connected to the drain electrode 13Bd of the second TFT 13B via the second contact hole 16b.

[0103] In the liquid crystal display device 100, a discharge-type pixel division drive is performed. When the gate signal supplied by the gate wiring GL changes from a low level to a high level, the first TFT 13A, the second TFT 13B, and the third TFT 13C turn on. As a result, the source signal from the source wiring SL is supplied to the first sub-pixel electrode 11a and the second sub-pixel electrode 11b via the first TFT 13A and the second TFT 13B, respectively, and the first liquid crystal capacitor Clc1 and the second liquid crystal capacitor Clc2 are charged. At this time, in the second sub-pixel Sp2, voltage division is performed according to the ratio of the on-resistance of the second TFT 13B and the on-resistance of the third TFT 13C, so the voltage applied to the second liquid crystal capacitor Clc2 is lower than the voltage applied to the first liquid crystal capacitor Clc1. Therefore, the first sub-pixel Sp1 can function as a relatively bright sub-pixel, and the second sub-pixel Sp2 can function as a relatively dark sub-pixel.

[0104] In the illustrated example, a pair of capacitance reduction electrodes 17A and 17B extend from the first auxiliary capacitance wiring CsL1. The pair of capacitance reduction electrodes 17A and 17B extend along the column direction and overlap the edge of the first sub-pixel electrode 11a parallel to the column direction in a plan view. In the illustrated example, a pair of capacitance reduction electrodes 17C and 17D extend from the second auxiliary capacitance wiring CsL2. The pair of capacitance reduction electrodes 17C and 17D extend along the column direction and overlap the edge of the second sub-pixel electrode 11b parallel to the column direction in a plan view. By providing such capacitance reduction electrodes 17A, 17B, 17C, and 17D, the electric field between the source wiring SL and the pixel electrode 11 can be shielded, thereby reducing the parasitic capacitance formed between the source wiring SL and the pixel electrode 11.

[0105] In this embodiment, the discharge wiring DcL is positioned to overlap the first boundary BD1 and the second boundary BD2 in a plan view, as shown in Figures 5A, 5B, and 8. In the illustrated example, the discharge wiring DcL is formed in the same layer as the source wiring SL (i.e., from the same source metal as the source wiring SL) and is covered by an interlayer insulating layer 16.

[0106] The pixel electrode 11 has multiple slits, some of which at least partially overlap the discharge wiring DcL in a plan view. In the illustrated example, the first slit s1 and the second slit s2 partially overlap the discharge wiring DcL in a plan view.

[0107] Furthermore, in this embodiment, the active matrix substrate 10 further includes a light-shielding layer 18 disposed on each of the first sub-pixel Sp1 and the second sub-pixel Sp2, as shown in Figures 5A, 5B, and 8. The light-shielding layer 18 includes a light-shielding portion 18a that is disposed to at least partially overlap each first slit s1 in a plan view. The light-shielding layer 18 also includes a further light-shielding portion 18b that is disposed to at least partially overlap each second slit s2 in a plan view. Hereinafter, the light-shielding portion 18a will be referred to as the "first light-shielding portion," and the further light-shielding portion 18b will be referred to as the "second light-shielding portion."

[0108] Each first slit s1 includes a portion that overlaps both the first light-shielding portion 18a and the discharge wiring DcL in a plan view, and a portion that overlaps the first light-shielding portion 18a but does not overlap the discharge wiring DcL in a plan view. Similarly, each second slit s2 includes a portion that overlaps both the second light-shielding portion 18b and the discharge wiring DcL in a plan view, and a portion that overlaps the second light-shielding portion 18b but does not overlap the discharge wiring DcL in a plan view.

[0109] The light-shielding layer 18 is formed from a conductive material and is given a predetermined potential. Here, the predetermined potential given to the light-shielding layer 18 is the same as the potential given to the auxiliary capacitance wiring CsL, and is the same as, for example, the potential given to the counter electrode 21 (common potential). In the illustrated example, the light-shielding layer 18 is formed in the same layer as the gate wiring GL (i.e., from the same gate metal as the gate wiring GL). The light-shielding layer 18 of the first sub-pixel Sp1 extends from the first auxiliary capacitance wiring CsL1 and extends in substantially the same direction as the discharge wiring DcL. The light-shielding layer 18 of the second sub-pixel Sp2 extends from the second auxiliary capacitance wiring CsL2 and extends in substantially the same direction as the discharge wiring DcL.

[0110] The discharge wiring DcL has a first wiring edge Le1 and a second wiring edge Le2 that define the width of the discharge wiring DcL. Focusing on the positions of the first wiring edge Le1 and the second wiring edge Le2 in the row direction, as shown in Figure 5A, the first wiring edge Le1 is located on the liquid crystal domain D (first liquid crystal domain) side of the first boundary BD1, and the second wiring edge Le2 is located on the liquid crystal domain A (third liquid crystal domain) side of the first boundary BD1. In other words, the first wiring edge Le1 is relatively located on the liquid crystal domain D side, and the second wiring edge Le2 is relatively located on the liquid crystal domain A side. Also, as shown in Figure 5B, the first wiring edge Le1 is located on the liquid crystal domain C (fourth liquid crystal domain) side of the second boundary BD2, and the second wiring edge Le2 is located on the liquid crystal domain B (second liquid crystal domain) side of the second boundary BD2. In other words, the first wiring edge Le1 is located relatively towards liquid crystal domain C, and the second wiring edge Le2 is located relatively towards liquid crystal domain B.

[0111] The first light-shielding portion 18a of the light-shielding layer 18 has a first light-shielding layer edge Se1 and a second light-shielding layer edge Se2 that define the width of the first light-shielding portion 18a. Focusing on the positions of the first light-shielding layer edge Se1 and the second light-shielding layer edge Se2 in the row direction, as shown in Figure 5A, the first light-shielding layer edge Se1 is located on the liquid crystal domain D (first liquid crystal domain) side of the first boundary BD1, and the second light-shielding layer edge Se2 is located on the liquid crystal domain A (third liquid crystal domain) side of the first boundary BD1. In other words, the first light-shielding layer edge Se1 is relatively located on the liquid crystal domain D side, and the second light-shielding layer edge Se2 is relatively located on the liquid crystal domain A side.

[0112] The second light-shielding portion 18b of the light-shielding layer 18 has a third light-shielding layer edge Se3 and a fourth light-shielding layer edge Se4 that define the width of the second light-shielding portion 18b. Focusing on the positions of the third light-shielding layer edge Se3 and the fourth light-shielding layer edge Se4 in the row direction, as shown in Figure 5B, the third light-shielding layer edge Se3 is located on the liquid crystal domain B (second liquid crystal domain) side of the second boundary BD2, and the fourth light-shielding layer edge Se4 is located on the liquid crystal domain C (fourth liquid crystal domain) side of the second boundary BD2. In other words, the third light-shielding layer edge Se3 is relatively located on the liquid crystal domain B side, and the fourth light-shielding layer edge Se4 is relatively located on the liquid crystal domain C side.

[0113] In the illustrated example, the first light-shielding portion 18a is positioned such that, in a plan view, its widthwise center substantially coincides with the widthwise center of the discharge wiring DcL, and the width of the first light-shielding portion 18a is greater than the width of the discharge wiring DcL. Therefore, the first wiring edge Le1 is located between the first boundary BD1 and the first light-shielding layer edge Se1, and the second wiring edge Le2 is located between the first boundary BD1 and the second light-shielding layer edge Se2. In other words, the first light-shielding portion 18a protrudes outward in the widthwise direction compared to the discharge wiring DcL.

[0114] Furthermore, in the illustrated example, the second light-shielding portion 18b is positioned such that, in a plan view, its widthwise center substantially coincides with the widthwise center of the discharge wiring DcL, and the width of the second light-shielding portion 18b is greater than the width of the discharge wiring DcL. Therefore, the second wiring edge Le2 is located between the second boundary BD2 and the third light-shielding layer edge Se3, and the first wiring edge Le1 is located between the second boundary BD2 and the fourth light-shielding layer edge Se4. In other words, the second light-shielding portion 18b protrudes outward in the widthwise direction compared to the discharge wiring DcL.

[0115] As described above, in the liquid crystal display device 100 of this embodiment, the first sub-pixel electrode 11a and the second sub-pixel electrode 11b each have a first slit s1, a second slit s2, a third slit s3, and a fourth s4.

[0116] Because the first slit s1, which extends approximately parallel to the director td of liquid crystal domain D, is located near the first boundary BD1, the number of liquid crystal molecules oriented approximately parallel to the director td in the vicinity of the first boundary BD1 increases (the probability of their existence increases). As a result, the area of ​​the dark line DL4 becomes smaller.

[0117] Similarly, because the second slit s2, which extends approximately parallel to the director tb of liquid crystal domain B, is located near the second boundary BD2, the number of liquid crystal molecules oriented approximately parallel to the director tb increases (the probability of their existence increases) near the second boundary BD2. As a result, the area of ​​the dark line DL2 becomes smaller.

[0118] Similarly, because the third slit s3, which extends approximately parallel to the director ta of liquid crystal domain A, is located near the third boundary BD3, the number of liquid crystal molecules oriented approximately parallel to the director ta increases (the probability of their existence increases) near the third boundary BD3. As a result, the area of ​​the dark line DL1 becomes smaller.

[0119] Similarly, because the fourth slit s4, which extends approximately parallel to the director tc of liquid crystal domain C, is located near the fourth boundary BD4, the number of liquid crystal molecules oriented approximately parallel to the director tc in the vicinity of the fourth boundary BD4 increases (the probability of their existence increases). As a result, the area of ​​the dark line DL3 becomes smaller.

[0120] Thus, by forming the first slit s1, second slit s2, third slit s3, and fourth slit s4 near the domain boundary of the pixel electrode 11, the area of ​​the dark lines formed near the domain boundary can be reduced. Since the dark lines can also be called the misalignment region, it can also be said that the misalignment in the misalignment region can be improved.

[0121] In the illustrated example, multiple first slits s1 are arranged so that the first long slit s1A is closest to the electrode end, and multiple second slits s2 are arranged so that the second long slit s2A is closest to the electrode end. Similarly, multiple third slits s3 are arranged so that the third long slit s3A is closest to the electrode end, and multiple fourth slits s4 are arranged so that the fourth long slit s4A is closest to the electrode end. This configuration makes it possible to more effectively reduce the area of ​​the dark lines.

[0122] Note that the number of each of the first slit s1, second slit s2, third slit s3, and fourth slit s4 is not limited to the example shown. The widths of the first slit s1, second slit s2, third slit s3, and fourth slit s4 are not particularly limited, but are, for example, 2 μm or more and 4 μm or less. The lengths of the first long slit s1A, second long slit s2A, third long slit s3A, and fourth long slit s4A are not particularly limited, but are, for example, 10 μm or more and 18 μm or less. The lengths of the first short slit s1B, second short slit s2B, third short slit s3B, and fourth short slit s4B are not particularly limited, but are, for example, 6 μm or more and 10 μm or less.

[0123] Furthermore, in the liquid crystal display device 100 of this embodiment, the discharge wiring DcL is arranged so as to overlap the first boundary BD1 and the second boundary BD2 in a plan view. Since the first boundary BD1 and the second boundary BD2 are regions where dark lines DL4 and DL2 are generated, the arrangement of the discharge wiring DcL so as to overlap the first boundary BD1 and the second boundary BD2 makes it possible to suppress the decrease in light utilization efficiency caused by the discharge wiring DcL (typically formed from a light-shielding material such as metal).

[0124] Furthermore, the liquid crystal display device 100 of this embodiment has a light-shielding layer 18 that is arranged to at least partially overlap the plurality of first slits s1 and the plurality of second slits s2 in a plan view. The effects of providing such a light-shielding layer 18 will be explained below in comparison with the comparative example liquid crystal display device 1000 shown in Figures 10A, 10B, and 11.

[0125] Figures 10A and 10B are cross-sectional views of the comparative example liquid crystal display device 1000, respectively, and Figure 11 is a plan view of the comparative example liquid crystal display device 1000. Figures 10A and 10B show cross-sections along the line 10A-10A' and the line 10B-10B' in Figure 11, respectively.

[0126] The comparative example liquid crystal display device 1000 differs from the liquid crystal display device 100 in that it does not have a light-shielding layer 18, as shown in Figures 10A, 10B, and 11. In the comparative example liquid crystal display device 1000, when displaying black, light leakage may occur near the first slit s1 and the second slit s2, potentially reducing the contrast ratio.

[0127] Figure 12 shows the results of a simulation of the transmittance distribution within the second sub-pixel Sp2 when displaying black for the comparative example liquid crystal display device 1000. From Figure 12, it can be seen that light leakage occurs near the first slit s1 and the second slit s2. This light leakage is caused by the application of an unintended voltage to the liquid crystal layer 30 near the first slit s1 and the second slit s2 because the potential applied to the discharge wiring DcL is different from the potential applied to the counter electrode 21.

[0128] In contrast, in the liquid crystal display device 100 of this embodiment, the light-shielding layer 18 is arranged so as to at least partially overlap the plurality of first slits s1 and the plurality of second slits s2 in a plan view, so that light leakage near the first slits s1 and the second slits s2 can be suppressed, and a decrease in the contrast ratio can be suppressed.

[0129] Figure 13 shows the results of orientation simulation to determine the transmittance distribution within the second sub-pixel Sp2 when displaying black in the liquid crystal display device 100 of this embodiment. From Figure 13, it can be seen that light leakage near the first slit s1 and the second slit s2 is suppressed.

[0130] Table 1 shows examples of calculated transmittance during white display, transmittance during black display, and contrast ratio for the comparative example liquid crystal display device 1000 and the liquid crystal display device 100 of this embodiment. Note that Table 1 shows relative values ​​with the values ​​for the comparative example liquid crystal display device 1000 set to 100%.

[0131] Table 1 shows that the liquid crystal display device 100 of this embodiment has an improved contrast ratio compared to the liquid crystal display device 1000 of the comparative example.

[0132] [Table 1]

[0133] Furthermore, if the light-shielding layer 18 is formed from a conductive material, it is preferable that the light-shielding layer 18 is given a predetermined potential (i.e., not electrically floating), as illustrated. If the light-shielding layer 18 is electrically floating, the potential of the light-shielding layer 18 will fluctuate, which may cause orientation disturbances in the liquid crystal layer 30 near the first slit s1 and the second slit s2.

[0134] [Embodiment 2] The liquid crystal display device 200 of this embodiment will be described with reference to Figures 14A, 14B, and 15. Figures 14A and 14B are schematic cross-sectional views of the liquid crystal display device 200, respectively, and Figure 15 is a schematic plan view of the liquid crystal display device 200. Figures 14A and 14B show cross-sections along the line 14A-14A' and the line 14B-14B' in Figure 15, respectively. The following description will focus on the differences between the liquid crystal display device 200 and the liquid crystal display device 100 of Embodiment 1.

[0135] In the liquid crystal display device 100 of Embodiment 1, the first light-shielding portion 18a of the light-shielding layer 18 is positioned such that, in a plan view, the widthwise center of the first light-shielding portion 18a substantially coincides with the widthwise center of the discharge wiring DcL. Similarly, the second light-shielding portion 18b of the light-shielding layer 18 is positioned such that, in a plan view, the widthwise center of the second light-shielding portion 18b substantially coincides with the widthwise center of the discharge wiring DcL.

[0136] In contrast, in the liquid crystal display device 200 of this embodiment, the first light-shielding portion 18a of the light-shielding layer 18 is positioned such that, as shown in Figures 14A and 15, in a plan view, the widthwise center of the first light-shielding portion 18a is shifted toward the first wiring edge Le1 than the widthwise center of the discharge wiring DcL. In the illustrated example, of the plurality of first slits s1, each first short slit s1B overlaps the first light-shielding portion 18a in its entirety in a plan view, while the first long slit s1A includes a portion that overlaps the first light-shielding portion 18a and a portion that does not overlap the first light-shielding portion 18a in a plan view (i.e., it partially overlaps the first light-shielding portion 18a).

[0137] Furthermore, as shown in Figures 14B and 15, the second light-shielding portion 18b of the light-shielding layer 18 is positioned such that, in a plan view, the widthwise center of the second light-shielding portion 18b is shifted toward the second wiring edge Le2 side than the widthwise center of the discharge wiring DcL. In the illustrated example, of the multiple second slits s2, each second short slit s2B overlaps the second light-shielding portion 18b in its entirety in a plan view, while the second long slit s2A includes a portion that overlaps the second light-shielding portion 18b and a portion that does not overlap the second light-shielding portion 18b in a plan view (i.e., it partially overlaps the second light-shielding portion 18b).

[0138] Thus, the liquid crystal display device 200 of this embodiment has a configuration in which, compared to the liquid crystal display device 100 of Embodiment 1, the first light-shielding portion 18a is shifted toward the first wiring edge Le1 of the discharge wiring DcL, and the second light-shielding portion 18b is shifted toward the second wiring edge Le2 of the discharge wiring DcL. By having such a configuration, the protrusion width of the first light-shielding portion 18a from the first wiring edge Le1 and the protrusion width of the second light-shielding portion 18b from the second wiring edge Le2 can be increased, thereby further suppressing light leakage.

[0139] While the widths of the first and second light-shielding portions 18a and 18b can be increased by simply increasing their widths while keeping the widths of the first and second light-shielding portions 18a and 18b substantially the same as the widths of the discharge wiring DcL, the protrusion width of the first light-shielding portion 18a from the first wiring edge Le1 and the protrusion width of the second light-shielding portion 18b from the second wiring edge Le2 can be increased, but in that case, a decrease in light utilization efficiency is a concern. As in this embodiment, by shifting the first light-shielding portion 18a toward the first wiring edge Le1 and the second light-shielding portion 18b toward the second wiring edge Le2, it is possible to suppress the decrease in light utilization efficiency while increasing the effect of suppressing light leakage.

[0140] Figure 16 shows the results of orientation simulation to determine the transmittance distribution within the second sub-pixel Sp2 when displaying black in the liquid crystal display device 200 of this embodiment. A comparison of Figure 16 and Figure 13 shows that in the liquid crystal display device 200 of this embodiment, light leakage near the first slit s1 and the second slit s2 is suppressed more effectively than in the liquid crystal display device 100 of Embodiment 1.

[0141] Table 2 shows an example of the calculated transmittance during white display, transmittance during black display, and contrast ratio for the liquid crystal display device 200 of this embodiment. For the calculations, the widths of the first light-shielding portion 18a and the second light-shielding portion 18b were assumed to be the same as those in the liquid crystal display device 100 of Embodiment 1.

[0142] Table 2 shows that, compared to the liquid crystal display device 100 of Embodiment 1, the liquid crystal display device 200 of this embodiment has further suppressed light leakage and an improved contrast ratio.

[0143] [Table 2]

[0144] From the viewpoint of suppressing a decrease in light utilization efficiency, as illustrated, when a plurality of first slits s1 include a first long slit s1A and a first short slit s1B, it is preferable to adopt a configuration in which the entirety of each first short slit s1B overlaps the first light-shielding portion 18a, and the first long slit s1A partially overlaps the first light-shielding portion 18a. Similarly, when a plurality of second slits s2 include a second long slit s2A and a second short slit s2B, it is preferable to adopt a configuration in which the entirety of each second short slit s2B overlaps the second light-shielding portion 18b, and the second long slit s2A partially overlaps the second light-shielding portion 18b.

[0145] [Regarding the protrusion width of the light-shielding layer] We will now explain the results of our verification of the preferred size of the protrusion width of the light-shielding layer 18 from the discharge wiring DcL.

[0146] First, as shown in Figure 17, the relationship between the distance d from the first wiring edge Le1 of the discharge wiring DcL and the luminance (black luminance) when displaying black (i.e., the light leakage profile) was calculated for the first long slit s1A and the first short slit s1B when the light-shielding layer 18 is not provided. Here, the calculation was performed assuming a protrusion width w1 of the first long slit s1A from the first wiring edge Le1 of 7.3 μm and a protrusion width w2 of the first short slit s1B of 3.5 μm.

[0147] The obtained light leakage profile is shown in Figure 18. From Figure 18, it can be seen that for both the first long slit s1A and the first short slit s1B, the light leakage is greatest when the distance d from the first wiring edge Le1 is around 1.4 μm to 1.6 μm.

[0148] Next, for the first short slit s1B in the case where the light-shielding layer 18 is provided, the protrusion width of the first light-shielding portion 18a from the first wiring edge Le1 of the discharge wiring DcL was varied, and the black luminance, white luminance, and contrast ratio were calculated and confirmed. Here, the protrusion width of the first light-shielding portion 18a is the distance d1 from the first wiring edge Le1 to the first light-shielding layer edge Se1 of the first light-shielding portion 18a in a plan view, as shown in Figure 19. The confirmation results are shown in Figure 20.

[0149] Figure 20 shows that increasing the protrusion width d1 of the first light-shielding portion 18a reduces black luminance and improves the contrast ratio. The decrease in black luminance tends to saturate when the protrusion width d1 exceeds 4 μm, and the improvement in the contrast ratio also tends to saturate when the protrusion width d1 exceeds 4 μm. Furthermore, Figure 20 shows that increasing the protrusion width d1 of the first light-shielding portion 18a reduces white luminance (decreasing almost linearly). This is because the aperture ratio decreases. Therefore, it can be said that there is a trade-off relationship between light leakage suppression and white luminance.

[0150] Considering that the peak in the light leakage profile shown in Figure 18 is around 1.4 μm to 1.6 μm, from the viewpoint of suppressing light leakage, it is preferable that the protrusion width d1 of the first light-shielding portion 18a be 1.4 μm or more.

[0151] Furthermore, considering the saturation trend of decreasing black luminance and improving contrast ratio, from the viewpoint of maintaining sufficiently high white luminance, it is preferable that the protrusion width d1 of the first light-shielding portion 18a be 4.0 μm or less.

[0152] The findings described above can also be applied to the protrusion width of the second light-shielding portion 18b from the second wiring edge Le2 of the discharge wiring DcL. Here, the protrusion width of the second light-shielding portion 18b is the distance d2 from the second wiring edge Le2 to the third light-shielding layer edge Se3 of the second light-shielding portion 18b in a plan view, as shown in Figure 21. From the viewpoint of suppressing light leakage, it is preferable that the protrusion width d2 of the second light-shielding portion 18b is 1.4 μm or more. Furthermore, from the viewpoint of maintaining a sufficiently high white brightness, it is preferable that the protrusion width d2 of the second light-shielding portion 18b is 4.0 μm or less.

[0153] [Regarding other configurations] In the above description, an example was given in which the light-shielding layer 18 is provided below the discharge wiring DcL (i.e., between the discharge wiring DcL and the substrate 10a), but embodiments of the present invention are not limited to this configuration. The light-shielding layer 18 may also be provided above the discharge wiring DcL (i.e., between the discharge wiring DcL and the liquid crystal layer 30).

[0154] Furthermore, although the above description illustrates a configuration in which the active matrix substrate 10 has a light-shielding layer 18, embodiments of the present invention are not limited to this configuration. The opposing substrate 20 may also have a light-shielding layer 18. When the opposing substrate 20 has a light-shielding layer 18, the light-shielding layer 18 is formed, for example, in the same layer as the black matrix. As illustrated, the configuration in which the active matrix substrate 10 has a light-shielding layer 18 is advantageous in that even if misalignment (bonding misalignment) occurs when bonding the active matrix substrate 10 and the opposing substrate 20, positional misalignment of the light-shielding layer 18 with respect to the first slit s1 and the second slit s2 does not occur. [Industrial applicability]

[0155] According to embodiments of the present invention, for example, in a VA mode liquid crystal display device in which an alignment division structure is formed by defining the pre-tilt direction with an alignment film, and a discharge-type pixel division drive technology is used, a decrease in contrast ratio can be suppressed. Liquid crystal display devices according to embodiments of the present invention are suitably used in applications requiring high-quality display, such as television receivers. [Explanation of Symbols]

[0156] 10 Active matrix substrate 10a substrate 11 Pixel electrodes 11a First sub-pixel electrode 11b Second subpixel electrode 12 First orientation film 13A 1st TFT 13B 2nd TFT 13C 3rd TFT 14 Gate Insulation Layer 15A 1st auxiliary capacitor electrode 15B 2nd auxiliary capacitor electrode 16 interlayer insulating layer 16a First Contact Hole 16b Second Contact Hole 17A, 17B, 17C, 17D Capacity reduction electrodes 18 Light blocking layer 18a 1st light shielding part 18b 2nd light shielding part 20 Opposing substrate 20a substrate 21 Counter electrode 22 Second-Oriented Membrane 30 liquid crystal layers 41, 42 Polarizing plates 100, 200 LCD display device 101 LCD display panel 102 Backlight A, B, C, D Liquid Crystal Domains ta, tb, tc, td Reference orientation direction P pixels Sp1: First subpixel Sp2: Second subpixel GL gate wiring SL Source Wiring DCL discharge wiring CsL auxiliary capacitor wiring s1 First slit s1A First long slit s1B First short slit s2 Second slit s2A Second long slit s2B Second short slit s3 Third slit s3A Third long slit s3B Third short slit s4 4th slit s4A 4th long slit s4B 4th short slit PA1, PA2 polarization axis PD1 First pre-tilt direction PD2 Second pre-tilt direction PD3 Third pre-tilt direction PD4 4th Pre-Tilt Direction BD1 1st boundary BD2 2nd boundary BD3 Third Boundary BD4 4th boundary DL1, DL2, DL3, DL4, DL5, DL6, DL7, DL8 Dark line Dis1 First Wiring Edge Le2 Second Wiring Edge SE1 First light-shielding layer edge Se2 Second light-shielding layer edge Se3 Third light-shielding layer edge Se4 4th light-shielding layer edge

Claims

1. A first substrate and a second substrate facing each other, A vertically aligned liquid crystal layer is provided between the first substrate and the second substrate, A liquid crystal display device having multiple pixels arranged in a matrix including multiple pixel rows and multiple pixel columns, The first substrate has gate wiring that supplies a gate signal to a corresponding pixel row among the plurality of pixel rows, source wiring that supplies a source signal to a corresponding pixel column among the plurality of pixel columns, and pixel electrodes provided for each of the plurality of pixels. The second substrate in the series has a counter electrode facing the pixel electrode, Each of the plurality of pixels includes a first sub-pixel and a second sub-pixel to which different voltages can be applied to the liquid crystal layer. The pixel electrode includes a first sub-pixel electrode provided on the first sub-pixel and a second sub-pixel electrode provided on the second sub-pixel. The first substrate is A first TFT electrically connected to the gate wiring, the source wiring, and the first sub-pixel electrode, A second TFT electrically connected to the gate wiring, the source wiring, and the second sub-pixel electrode, The gate wiring, the second TFT, and the third TFT electrically connected to the second sub-pixel electrode, Discharge wiring electrically connected to the third TFT, It has, The pixel electrode has at least one slit that at least partially overlaps the discharge wiring in a plan view, A liquid crystal display device wherein the first substrate or the second substrate has a light-shielding layer including a light-shielding portion that is arranged to at least partially overlap the slit in a plan view.

2. The liquid crystal display device according to claim 1, wherein the slit includes a portion that overlaps both the light-shielding portion and the discharge wiring in a plan view, and a portion that overlaps the light-shielding portion but does not overlap the discharge wiring in a plan view.

3. The liquid crystal display device according to claim 1 or 2, wherein the potential supplied to the discharge wiring is different from the potential supplied to the counter electrode.

4. The liquid crystal display device according to claim 1 or 2, wherein the first substrate has the light-shielding layer.

5. The light-shielding layer is formed from a conductive material and is subjected to a predetermined potential, as described in claim 4.

6. The first substrate further has auxiliary capacitance wiring, The liquid crystal display device according to claim 5, wherein the predetermined potential applied to the light-shielding layer is the same as the potential applied to the auxiliary capacitance wiring.

7. The discharge wiring is formed in the same layer as the source wiring. The liquid crystal display device according to claim 4, wherein the light-shielding layer is formed in the same layer as the gate wiring.

8. The first substrate further comprises a first alignment film provided between the pixel electrode and the liquid crystal layer, The second substrate further comprises a second alignment film provided between the counter electrode and the liquid crystal layer, Each of the first subpixel and the second subpixel has a plurality of liquid crystal domains whose reference orientation directions, defined by the first alignment layer and the second alignment layer, are different from each other. The plurality of liquid crystal domains include a first liquid crystal domain whose reference orientation direction is a first direction, a second liquid crystal domain whose reference orientation direction is a second direction, a third liquid crystal domain whose reference orientation direction is a third direction, and a fourth liquid crystal domain whose reference orientation direction is a fourth direction. The at least one slit is at least one first slit extending substantially parallel to the first direction, and includes at least one first slit located near a first boundary which is the boundary between the first liquid crystal domain and other liquid crystal domains. The liquid crystal display device according to claim 1 or 2, wherein the discharge wiring is arranged to overlap the first boundary in a plan view.

9. The light-shielding layer extends in substantially the same direction as the discharge wiring extends. The discharge wiring comprises a first wiring edge and a second wiring edge that define the width of the discharge wiring, the first wiring edge located relatively to the first liquid crystal domain side and the second wiring edge located relatively to the other liquid crystal domain side. The light-shielding portion comprises a first light-shielding layer edge and a second light-shielding layer edge that define the width of the light-shielding portion, the first light-shielding layer edge located relatively on the side of the first liquid crystal domain and the second light-shielding layer edge located relatively on the side of the other liquid crystal domain. The liquid crystal display device according to claim 8, wherein the first wiring edge is located between the first boundary and the first light-shielding layer edge.

10. The liquid crystal display device according to claim 9, wherein the light-shielding portion is arranged such that, in a plan view, the widthwise center of the light-shielding portion is shifted toward the first wiring edge side than the widthwise center of the discharge wiring.

11. The liquid crystal display device according to claim 9, wherein the distance from the first wiring edge to the first light-shielding layer edge in a plan view is 1.4 μm or more.

12. The liquid crystal display device according to claim 9, wherein the distance from the first wiring edge to the first light-shielding layer edge in a plan view is 4.0 μm or less.

13. The liquid crystal display device according to claim 8, wherein the at least one first slit includes a first long slit and at least one first short slit shorter than the first long slit.

14. Each of the at least one first short slits is such that, in a plan view, its entirety overlaps the light-shielding portion. The liquid crystal display device according to claim 13, wherein the first long slit includes a portion that overlaps with the light-shielding portion and a portion that does not overlap with the light-shielding portion in a plan view.

15. The first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are arranged in a 2x2 grid, The first liquid crystal domain and the second liquid crystal domain are adjacent to each other in an oblique direction that is inclined with respect to the row and column directions. The pixel electrode has at least one second slit formed in a region corresponding to the second liquid crystal domain and extending substantially parallel to the second direction, and having at least one second slit located near a second boundary which is the boundary between the second liquid crystal domain and other liquid crystal domains. The discharge wiring is arranged so as to overlap with the second boundary in a plan view. The liquid crystal display device according to claim 8, wherein the light-shielding layer includes a further light-shielding portion that is arranged to at least partially overlap the at least one second slit in a plan view.

16. The third liquid crystal domain is adjacent to the first liquid crystal domain in the row direction and adjacent to the second liquid crystal domain in the column direction. The fourth liquid crystal domain is adjacent to the first liquid crystal domain in the column direction and adjacent to the second liquid crystal domain in the row direction. The first boundary is the boundary between the first liquid crystal domain and the third liquid crystal domain, The liquid crystal display device according to claim 15, wherein the second boundary is the boundary between the second liquid crystal domain and the fourth liquid crystal domain.

17. The liquid crystal display device according to claim 8, wherein the first direction, the second direction, the third direction, and the fourth direction are four directions in which the difference between any two directions is approximately equal to an integer multiple of 90°.

18. The liquid crystal display device according to claim 8, wherein the first direction and the second direction form an angle of approximately 180°.

19. The liquid crystal display device according to claim 8, wherein each of the first alignment film and the second alignment film is a photoalignment film.

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