JP2010048905A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device that prevents the degradation of display quality to pixels having various pitches. <P>SOLUTION: In the liquid crystal display device (100), a pixel electrode (124) includes a first partial electrode (124a) having edges (124s1, 124s2) extending in a first direction (F1) and a second partial electrode (124b) having edges (124s3, 124s4) extending in a second direction (F2) orthogonal to the first direction (F1). An angle (θ) formed by a column direction and the first direction (F1) is different from an angle (90°-θ) formed by the column direction and the second direction (F2) and a length (pa) of a component formed by projecting a pixel pitch (P) in the column direction in the second direction (F2) is different from a length (pb) of a component formed by projecting the pixel pitch (P) in the column direction in the first direction (F1). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device.

  The liquid crystal display device is used not only as a small display device such as a display unit of a mobile phone but also as a large television. The viewing angle of a TN (Twisted Nematic) mode liquid crystal display device that has been frequently used in the past has been relatively narrow, but in recent years, a wide viewing angle liquid crystal display such as an IPS (In-Plane-Switching) mode and a VA (Vertical Alignment) mode. A device has been made. Among such wide viewing angle modes, the VA mode can realize a high contrast ratio, and is used in many liquid crystal display devices.

  As one type of VA mode, an MVA (Multi-domain Vertical Alignment) mode in which a plurality of liquid crystal domains are formed in one pixel region is known. In the liquid crystal display device of these modes, an alignment regulating structure is provided on at least one liquid crystal layer side of a pair of substrates facing each other with the vertical alignment type liquid crystal layer interposed therebetween. The alignment regulating structure is, for example, a linear slit (opening) or a rib (projection structure) provided on the electrode. Of these MVA modes, those in which electrode slits are provided on both substrates are particularly called PVA (Patented Vertical Alignment) modes.

  At least when a voltage is applied to the liquid crystal layer, an alignment regulating force is applied from one or both sides of the liquid crystal layer by the alignment regulating structure, and the liquid crystal molecules are aligned perpendicular to the direction in which the alignment regulating structure extends. . In an MVA mode liquid crystal display device, the alignment control structure has linear components orthogonal to each other, and a plurality of liquid crystal domains (typically four liquid crystal domains) having different alignment directions are formed, thereby improving viewing angle characteristics. Is planned.

  Patent Document 1 discloses that zigzag (bent) domain regulating means (alignment regulating structure) is formed on the liquid crystal layer side of the TFT substrate and the counter substrate. With such an alignment regulation structure, liquid crystal domains are formed in four directions, and viewing angle characteristics are improved. Patent Document 1 discloses that not only the alignment regulating structure but also the pixel electrode is formed in a bent shape. As a result, misalignment between the alignment regulation direction caused by the oblique electric field near the edge of the pixel electrode and the alignment regulation direction due to the ribs and slits is suppressed, and the occurrence of alignment disorder is suppressed.

  Moreover, it is known that the display characteristics of a liquid crystal display device change according to the arrangement of the alignment regulating structure (see, for example, Patent Document 2). In Patent Document 2, the width of an alignment regulating structure (for example, a rib or a slit) provided on the liquid crystal layer side of the counter substrate, or the alignment regulating structure (for example, a slit) provided on the liquid crystal layer side of the TFT substrate. It is disclosed that the adjustment of the width of the liquid crystal region (liquid crystal domain region) defined between them is more effective in improving the response speed than the width of.

In Patent Document 2, the relationship between the width of the liquid crystal domain region and the display characteristics is examined. The response speed decreases as the width of the liquid crystal region increases. In addition, the aperture ratio decreases as the width of the liquid crystal region decreases. For this reason, Patent Document 2 describes that the width of the liquid crystal domain region is set within an appropriate range in consideration of the response speed and the aperture ratio. In addition, the width of the alignment regulating structure provided on the liquid crystal layer side of the two substrates is set within a predetermined range due to the aperture ratio and design problems.
Japanese Patent Laid-Open No. 11-242225 JP 2005-292515 A

  Currently, liquid crystal display devices with various resolutions and sizes are manufactured, and in general, liquid crystal display devices with various sizes for each resolution are manufactured. For example, television apparatuses using liquid crystal display devices of various sizes conforming to a high definition standard with a resolution of 1366 × 768 and a full high definition standard with a resolution of 1920 × 1080 have been manufactured.

  The pixel pitch of the liquid crystal display device is determined based on the resolution and size of the liquid crystal display device. The inventor of the present application can arrange the alignment regulating structure with an appropriate distance and width considering the response speed and the aperture ratio for a pixel with a certain pitch, but with a pixel with a different pitch. It has been found that the alignment regulating structures cannot be arranged at an appropriate distance and width, and in this case, at least one of the response speed and the aperture ratio is lowered, and the display quality is lowered.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal display device that suppresses deterioration in display quality with respect to pixels having various pitches.

  The liquid crystal display device according to the present invention includes a plurality of pixel electrodes each defining a pixel, an active matrix substrate having a plurality of pixel electrodes arranged in a matrix of a plurality of rows and a plurality of columns, and a counter electrode. And a vertical alignment type liquid crystal layer provided between the active matrix substrate and the counter substrate, wherein each of the plurality of pixel electrodes is a first partial electrode. And a second partial electrode, and the first partial electrode is parallel to a first direction oblique to a row direction defining a direction of the plurality of rows in which the plurality of pixel electrodes are arranged. The second partial electrode has a third edge and a fourth edge extending in parallel with a second direction orthogonal to the first direction, and is opposed to the second edge. Board A linear first opposing alignment regulating structure provided on the liquid crystal layer side; and a linear second opposing alignment regulating structure provided on the liquid crystal layer side, wherein the first opposing The alignment regulating structure extends in parallel with the first direction so as to face the first partial electrodes of the plurality of pixel electrodes, and the second opposed alignment regulating structure includes the plurality of pixel electrodes. Opposing each of the second partial electrodes and extending in parallel with the second direction, the angle formed by the first direction and the row direction is different from the angle formed by the second direction and the row direction. The length of the component in which the pitch of the pixel in the row direction is projected in the first direction is different from the length of the component in which the pitch of the pixel in the row direction is projected in the second direction.

  In one embodiment, the width of the first partial electrode along a direction parallel to the second direction is different from the width of the second partial electrode along a direction parallel to the first direction.

  In one embodiment, an angle formed between the first direction and the row direction is smaller than an angle formed between the second direction and the row direction, and a pitch of the pixels in the row direction is projected in the first direction. The length of the component is larger than the length of the component obtained by projecting the pitch in the row direction of the pixel in the second direction.

  In one embodiment, the liquid crystal layer is positioned between a first liquid crystal domain and a second liquid crystal domain located between the first partial electrode and the counter electrode, and between the second partial electrode and the counter electrode. A third liquid crystal domain and a fourth liquid crystal domain, and the first liquid crystal domain and the second liquid crystal domain extend in parallel with the first direction when a voltage is applied to at least the liquid crystal layer. A liquid crystal molecule having an orientation component that is orthogonal to each other with respect to the opposing alignment regulating structure, wherein the third liquid crystal domain and the fourth liquid crystal domain are at least when a voltage is applied to the liquid crystal layer; Liquid crystal molecules having alignment azimuth components that are orthogonal to each other with respect to the second opposing alignment regulating structure extending in parallel with the second direction are included.

  In one embodiment, the active matrix substrate includes a first pixel alignment regulating structure corresponding to the first partial electrode on the liquid crystal layer side, and a second pixel alignment corresponding to the second partial electrode on the liquid crystal layer side. And a restriction structure, wherein the first pixel alignment restriction structure includes the first edge and the second edge of the first partial electrode, and the second pixel alignment restriction structure includes the first pixel alignment restriction structure. Including the third edge and the fourth edge of the second partial electrode, each of the first counter-alignment regulating structure and the second counter-alignment regulating structure including at least one rib or slit, The liquid crystal layer includes at least one first liquid crystal domain region in which the first liquid crystal domain is formed and at least one second liquid crystal domain in which the second liquid crystal domain is formed. A first liquid crystal domain region, at least one third liquid crystal domain region in which the third liquid crystal domain is formed, and at least one fourth liquid crystal domain region in which the fourth liquid crystal domain is formed. Each of the domain region and the second liquid crystal domain region is defined between the first counter alignment regulating structure and the first pixel alignment regulating structure, and the third liquid crystal domain region and the fourth liquid crystal Each of the domain regions is defined between the second opposing alignment restriction structure and the second pixel alignment restriction structure.

  In one embodiment, the widths of the first liquid crystal domain region, the second liquid crystal domain region, the third liquid crystal domain region, and the fourth liquid crystal domain region are within a predetermined range.

  In one embodiment, the width of each of the first liquid crystal domain region, the second liquid crystal domain region, the third liquid crystal domain region, and the fourth liquid crystal domain region is in a range of 18 μm or more and less than 23.5 μm.

  In one embodiment, the liquid crystal display device further includes a first polarizing plate provided on the active matrix substrate, and a second polarizing plate provided on the counter substrate, wherein the first polarizing plate and the One polarizing plate of the second polarizing plates includes the first direction and the intermediate direction between the column direction and the row direction that define the direction of the plurality of columns in which the plurality of pixel electrodes are arranged. The first polarizing plate and the second polarizing plate have a transmission axis that is shifted by an angle with the row direction, and the other polarizing plate of the first polarizing plate and the second polarizing plate has the first direction with respect to a direction orthogonal to the intermediate direction. The transmission axis is shifted by an angle between the direction and the row direction.

  In one embodiment, the first edge of the first partial electrode is continuous with the third edge of the second partial electrode, and the second edge of the first partial electrode is the second edge of the second partial electrode. It is continuous with the fourth edge.

  In one embodiment, at least one of the first opposed alignment regulating structure and the second opposed alignment regulating structure includes a plurality of ribs or slits arranged in parallel to each other, and Of the one-pixel alignment-regulating structure and the second pixel-alignment-controlling structure, the pixel alignment-controlling structure corresponding to the at least one counter-alignment-controlling structure is at a position facing between the plurality of ribs or slits. Includes slits or ribs provided.

  In one embodiment, the number of each of the first liquid crystal domain region and the second liquid crystal domain region is different from the number of each of the third liquid crystal domain region and the fourth liquid crystal domain region.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display device which suppressed the display quality fall with respect to the pixel of various pitches can be provided.

  Hereinafter, embodiments of a liquid crystal display device according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments.

  First, the liquid crystal display device 100 of the present embodiment will be described with reference to FIGS. The liquid crystal display device 100 of this embodiment includes an active matrix substrate 120 having a pixel electrode 124 and an alignment film 126 provided on an insulating substrate 122, and a counter electrode 144 and an alignment film 146 provided on an insulating substrate 142. A counter substrate 140 and a liquid crystal layer 160 provided between the active matrix substrate 120 and the counter substrate 140 are provided. The active matrix substrate 120 and the counter substrate 140 are provided with polarizing plates (not shown), and the transmission axes of the polarizing plates have a crossed Nicols relationship. The active matrix substrate 120 is provided with wiring and insulating layers (not shown), and the counter substrate 140 is provided with a color filter layer (not shown). The thickness of the liquid crystal layer 160 is substantially constant.

  In the liquid crystal display device 100, the plurality of pixels are arranged in a matrix of a plurality of rows and a plurality of columns. For example, in a liquid crystal display device that performs color display using R (red), G (green), and B (blue) as primary colors, one color is represented by three pixels of R, G, and B. A pixel is defined by a pixel electrode 124.

  The liquid crystal display device 100 operates in the VA mode. The alignment films 126 and 146 are vertical alignment films. The liquid crystal layer 160 is a vertical alignment type liquid crystal layer. Here, the “vertical alignment type liquid crystal layer” refers to a liquid crystal layer in which the liquid crystal molecular axes (also referred to as “axis orientation”) are aligned at an angle of about 85 ° or more with respect to the surfaces of the vertical alignment films 126 and 146. Say. The liquid crystal layer 160 includes a nematic liquid crystal material having negative dielectric anisotropy, and display is performed in a normally black mode in combination with a polarizing plate arranged in a crossed Nicol arrangement. When no voltage is applied to the liquid crystal layer 160, the liquid crystal molecules 162 of the liquid crystal layer 160 are aligned substantially parallel to the normal direction of the main surfaces of the alignment films 126 and 146. When a voltage higher than a predetermined voltage is applied to the liquid crystal layer 160, the liquid crystal molecules 162 of the liquid crystal layer 160 are aligned substantially parallel to the main surfaces of the alignment films 126 and 146. Here, the active matrix substrate 120 and the counter substrate 140 have the alignment films 126 and 146, respectively, but at least one of the active matrix substrate 120 and the counter substrate 140 has the corresponding alignment films 126 and 146. May be. However, from the viewpoint of alignment stability, it is preferable that both the active matrix substrate 120 and the counter substrate 140 have alignment films 126 and 146, respectively.

  Hereinafter, the pixel structure of the liquid crystal display device 100 will be described with reference to FIGS. In the liquid crystal display device 100, the pixel electrodes 124 are arranged in a matrix of a plurality of rows and a plurality of columns, and the row direction (x direction) is defined by the direction of the plurality of rows in which the pixel electrodes 124 are arranged, The column direction (y direction) is defined by the direction of a plurality of columns in which the pixel electrodes 124 are arranged. FIG. 2 shows only three pixel electrodes 124 arranged side by side in the row direction (x direction). 3 and 4 show one pixel electrode 124 in an enlarged manner.

  In the liquid crystal display device 100, the pixel electrode 124 includes a first partial electrode 124a and a second partial electrode 124b. Here, the first partial electrode 124a extends in a direction F1 oblique to the x direction, and the second partial electrode 124b extends in a direction F2 orthogonal to the direction F1. In the following description of the present specification, the direction F1 is also referred to as a first direction F1, and the direction F2 is also referred to as a second direction F2.

  The boundary line between the first partial electrode 124a and the second partial electrode 124b is parallel to the x direction, and when the angle between the first direction F1 and the x direction is denoted by θ, the boundary between the second direction F2 and the x direction is formed. The angle is 90 ° −θ. The angle formed between the direction F1 and the x direction is different from the angle formed between the direction F2 and the x direction, and the angle θ is an angle other than 45 °. Thus, the pixel electrode 124 has an asymmetric shape with respect to the x direction. For example, the angle formed by the first direction F1 and the x direction is 30 °, and the angle formed by the second direction F2 and the x direction is 60 °.

  The first partial electrode 124a is electrically connected to the second partial electrode 124b. Here, the first partial electrode 124a is continuous with the second partial electrode 124b. In the following description of the present specification, among the pixels defined by the pixel electrode 124, the region defined by the first partial electrode 124a is also referred to as a first pixel region P1, and the region defined by the second partial electrode 124b Also referred to as a second pixel region P2.

Here, focusing on the pixel electrodes 124 arranged in the row direction, the first partial electrodes 124a of the pixel electrodes 124 are arranged in parallel to each other, and the second partial electrodes 124b of the pixel electrodes 124 are arranged in parallel to each other. Has been. Further, the length h _a of the first partial electrode 124a projected onto the y-axis is equal to the length h _b of the second partial electrode 124b projected onto the y-axis, and the area of the first partial electrode 124a is equal to that of the second partial electrode 124b. Equal to the area.

  The pixel electrode 124 has edges 124s1 to 124s6. In the pixel electrode 124, the edge 124s1 is continuous with the edge 124s3, and the angle formed by the edge 124s1 and the edge 124s3 is 90 °. The edge 124s2 is continuous with the edge 124s4, and the angle between the edge 124s2 and the edge 124s4 is 90 °. The edge 124s1 and the edge 124s2 extend in parallel with the direction F1, and the edge 124s3 and the edge 124s4 extend in parallel with the direction F2. The edge 124s5 parallel to the x direction connects the edge 124s1 and the edge 124s2, and the edge 124s6 parallel to the x direction connects the edge 124s3 and the edge 124s4. The lengths of the edges 124s5 and 124s6 are shorter than the edges 124s1 to 124s4.

  On the counter substrate 140 on the liquid crystal layer 160 side, a linear counter alignment regulating structure 140D that defines the alignment direction of the liquid crystal molecules 162 is provided. The counter alignment regulating structure 140D includes a first alignment regulating structure 140D1 corresponding to the first partial electrode 124a and a second alignment regulating structure 140D2 corresponding to the second partial electrode 124b. Here, the first alignment regulation structure 140D1 is the rib 140a, and the second alignment regulation structure 140D2 is the ribs 140b1 and 140b2. The ribs 140a, 140b1, and 140b2 are provided closer to the liquid crystal layer 160 than the counter electrode 144 is. The rib 140a extends in parallel with the edges 124s1 and 124s2 of the pixel electrode 124, and the ribs 140b1 and 140b2 extend in parallel with the edges 124s3 and 124s4 of the pixel electrode 124.

  In addition, a slit 120 b is provided on the liquid crystal layer 160 side of the active matrix substrate 120. For example, the slit 120 b is provided in the pixel electrode 124. When viewed from the normal direction of the display screen, the slit 120b is provided at a corresponding position between the rib 140b1 and the rib 140b2.

  The ribs 140a, 140b1, 140b2 and the slit 120b are each provided in a strip shape (strip shape). The rib 140a functions to align the liquid crystal molecules 162 in a direction perpendicular to the first direction F1 in which the ribs 140a extend by aligning the liquid crystal molecules 162 substantially perpendicular to the side surfaces thereof. Further, the ribs 140b1 and 140b2 function to align the liquid crystal molecules 162 substantially perpendicular to the side surfaces thereof, thereby aligning the liquid crystal molecules 162 in a direction orthogonal to the second direction F2 in which the ribs 140b1 and 140b2 extend.

  The slit 120b generates an oblique electric field in the liquid crystal layer 160 in the vicinity of the edge of the slit 120b when a potential difference is formed between the pixel electrode 124 and the counter electrode 144 and a voltage is applied to the liquid crystal layer 160. It acts to align the liquid crystal molecules 162 in a direction orthogonal to the extending direction F2 of 120b. Further, the edges 124s1 to 124s4 of the pixel electrode 124 also operate in the same manner as the slit 120b. Specifically, when a potential difference is formed between the pixel electrode 124 and the counter electrode 144, an oblique electric field is generated in the liquid crystal layer 160 near the edges of the edges 124s1 to 124s4 of the pixel electrode 124, and the edges 124s1 to 124s1. It acts to align the liquid crystal molecules 162 in a direction orthogonal to the directions F1 and F2 extending in parallel with 124s4.

  In the first pixel region P1, the edge 124s1, the rib 140a, and the edge 124s2 of the pixel electrode 124 are disposed substantially in parallel with each other, and a liquid crystal domain region is formed therebetween. When a voltage is applied to the liquid crystal layer 160, the liquid crystal molecules 162 have an azimuth angle component in the direction from the back surface to the front surface along the major axis between the edge 124s1 of the pixel electrode 124 and the rib 140a. It is oriented so as to be opposite and orthogonal to the rib 140a. When a voltage is applied to the liquid crystal layer 160, the liquid crystal molecules 162 have an azimuth component in the direction from the back surface to the front surface along the major axis between the rib 140a and the edge 124s2 of the pixel electrode 124. Oriented to 140a and orthogonal to ribs 140a. Thus, the orientation direction of the liquid crystal molecules 162 in the first pixel region P1 is orthogonal to the rib 140a. In the following description of the present specification, a liquid crystal domain having an azimuth angle component from one side with respect to the rib 140a in which the liquid crystal molecules 162 extend in the first direction F1 in the liquid crystal layer 160 is referred to as a liquid crystal domain D1. A liquid crystal domain in which the molecules 162 have an azimuth angle component from the other side with respect to the rib 140a is referred to as a liquid crystal domain D2. In the liquid crystal layer 160, a region between the edge 124s1 of the pixel electrode 124 and the rib 140a is also referred to as a first liquid crystal domain region R1, and a region between the rib 140a and the edge 124s2 of the pixel electrode 124 is a second liquid crystal. Also referred to as domain region R2.

  In the second pixel region P2, the edge 124s3, the rib 140b1, the slit 120b, the rib 140b2, and the edge 124s4 of the pixel electrode 124 are disposed substantially parallel to each other, and a liquid crystal domain region is formed therebetween. When a voltage is applied to the liquid crystal layer 160, the liquid crystal molecules 162 have an azimuth component in the direction from the back surface to the front surface along the major axis between the edge 124s3 of the pixel electrode 124 and the rib 140b1. The liquid crystal molecules 162 are oriented so as to face each other and orthogonal to the ribs 140b1. Between the ribs 140b1 and the slits 120b, the liquid crystal molecules 162 have an azimuth component in the direction from the back to the front along the long axis. And oriented so as to be orthogonal to the rib 140b1. Further, when a voltage is applied to the liquid crystal layer 160, the azimuth angle component in the direction from the back surface to the front surface along the major axis of the liquid crystal molecules 162 is between the slit 120b and the rib 140b2, and the rib 140b2 In addition, the liquid crystal molecules 162 are aligned so as to be orthogonal to the ribs 140b2 and between the ribs 140b2 and the edge 124s4 of the pixel electrode 124, the azimuth angle component in the direction from the back surface to the front surface along the major axis thereof is the rib 140b2. And oriented so as to be orthogonal to the rib 140b2.

  Thus, the orientation direction of the liquid crystal molecules 162 in the second pixel region P2 is orthogonal to the ribs 140b1 and 140b2. In the following description of the present specification, in the liquid crystal layer 160, a liquid crystal domain having an azimuth component from one side with respect to the ribs 140b1 and 140b2 in which the liquid crystal molecules 162 extend in the second direction F2 is referred to as a liquid crystal domain D3. A liquid crystal domain in which the liquid crystal molecules 162 have an azimuth angle component from the other side with respect to the ribs 140b1 and 140b2 is referred to as a liquid crystal domain D4. The region forming the liquid crystal domain D3 is also referred to as a third liquid crystal domain region R3. Of these, the region between the edge 124s3 of the pixel electrode 124 and the rib 140b1 is also referred to as the liquid crystal domain region R3α, and the slit 120b and the rib 140b2 The region between is also referred to as a liquid crystal domain region R3β. In addition, a region that forms the liquid crystal domain D4 is also referred to as a fourth liquid crystal domain region R4. Of these, a region between the rib 140b1 and the slit 120b in the liquid crystal layer 160 is also referred to as a liquid crystal domain region R4α, and the rib 140b2 and the pixel A region between the edge 124s4 of the electrode 124 is also referred to as a liquid crystal domain region R4β. Thus, in the second pixel region P2, two liquid crystal domain regions R3α and R3β that form the liquid crystal domain D3 and two liquid crystal domain regions R4α and R4β that form the liquid crystal domain D4 are formed.

  As described above, in the first and second liquid crystal domains D1 and D2, the liquid crystal molecules 162 are aligned perpendicular to the ribs 140a, and the number of liquid crystal domain regions R1 forming the first liquid crystal domain D1 is the second liquid crystal. It is equal to the number of liquid crystal domain regions R2 forming the domain D2. In the third and fourth liquid crystal domains D3 and D4, the liquid crystal molecules 162 are aligned so as to be orthogonal to the ribs 140b1 and 140b2, and the number of liquid crystal domain regions R3α and R3β forming the third liquid crystal domain D3 is the number of the fourth liquid crystal domains. It is equal to the number of liquid crystal domain regions R4α and R4β that form D4. Each of the liquid crystal domain regions R1, R2, R3α, R3β, R4α, and R4β has a parallelogram shape, and its long side extends in the first direction F1 or the second direction F2, and its short side is in the x direction. It extends in parallel.

  In this specification, the alignment direction of the liquid crystal molecules at the center of the liquid crystal domain when a voltage is applied is referred to as a reference alignment direction, and the direction from the back surface to the front surface along the major axis of the liquid crystal molecules in the reference alignment direction. Azimuth angle component (that is, the azimuth angle component obtained by projecting the reference alignment direction onto the main surface of the alignment film 126 or the alignment film 146) is referred to as a reference alignment direction. The reference orientation characterizes the corresponding liquid crystal domain and has a dominant influence on the viewing angle characteristics of each liquid crystal domain. Specifically, the reference alignment directions of the liquid crystal domains are set so that the difference between any two directions is four directions substantially equal to an integral multiple of 90 °. The reference orientation of the liquid crystal domain D1 is 180 ° different from the reference orientation of the liquid crystal domain D2, and the reference orientation of the liquid crystal domain D3 is 180 ° different from the reference orientation of the liquid crystal domain D4.

  Here, the horizontal direction (left-right direction) of the display screen (paper surface) is taken as a reference for the azimuth angle direction, and the counterclockwise direction is taken positively. When the counterclockwise direction is positive), the reference orientations of the liquid crystal domains D1 to D4 are θ + 90 °, θ + 270 °, θ °, and θ + 180 °, respectively. One of the two polarizing plates (not shown) has a transmission axis in the direction of θ + 45 ° −θ + 225 ° rotated by an angle θ with respect to an intermediate direction between the x direction and the y direction. The other polarizing plate has a transmission axis in the direction of θ + 135 ° −θ + 315 ° rotated by an angle θ with respect to a direction orthogonal to the intermediate direction.

  For example, when the angle θ formed by the first direction F1 and the x direction is 30 °, the azimuth angles of the reference orientations of the liquid crystal domains D1 to D4 are 120 °, 300 °, 30 °, and 210 °, respectively. . The transmission axis of one polarizing plate is in the direction of 75 ° -255 °, and the transmission axis of the other polarizing plate is in the direction of 165 ° -345 °. As described above, the reference alignment directions of the four liquid crystal domains D1 to D4 indicate the middle direction between the adjacent transmission axis directions of the two polarizing plates, and light is efficiently used.

  In the liquid crystal display device 100 shown in FIG. 2, the ribs 140a, 140b1, and 140b2 are provided as the counter alignment regulating structure 140D on the liquid crystal layer 160 side of the counter substrate 140. However, the present invention is not limited to this. . Instead of the ribs 140a, 140b1, and 140b2, a slit may be provided on the counter substrate 140 on the liquid crystal layer 160 side as the counter alignment regulating structure 140D. As described above, each of the liquid crystal domains D1 to D4 includes the liquid crystal molecules 162 having alignment azimuth components that face each other at right angles to the first and second opposing alignment regulating structures 140D1 and 140D2 when a voltage is applied. .

  In the liquid crystal display device 100 shown in FIG. 2, the slit 120b is provided on the liquid crystal layer 160 side of the active matrix substrate 120, but the present invention is not limited to this. A rib may be provided on the liquid crystal layer 160 side of the active matrix substrate 120 in place of the slit 120b.

  On the liquid crystal layer 160 side of the active matrix substrate 120, a linear pixel alignment regulating structure 120D that defines the alignment direction of the liquid crystal molecules 162 is provided. The pixel alignment regulating structure 120D includes a first pixel alignment regulating structure 120D1 corresponding to the first partial electrode 124a and a second pixel alignment regulating structure 120D2 corresponding to the second partial electrode 124b. The first pixel alignment regulating structure 120D1 includes the edges 124s1 and 124s2 of the pixel electrode 124, and the second pixel alignment regulating structure 120D2 includes the edges 124s3 and 124s4 of the pixel electrode 124. Further, the second pixel alignment regulating structure 120D2 further includes a slit 120b.

  In the liquid crystal display device 100, the pixel has an asymmetric structure with respect to the x direction, and the number of ribs 140a corresponding to the first partial electrode 124a is equal to the number of ribs 140b1 and 140b2 corresponding to the second partial electrode 124b. The liquid crystal domains D3 and D4 are divided into more liquid crystal domain regions than the liquid crystal domains D1 and D2. In the first pixel region P1, the number of the liquid crystal domain regions forming the liquid crystal domain D1 and the liquid crystal domain D2 whose reference orientation directions are different from each other by 180 ° is Na, and the reference orientation directions are 180 ° in the second pixel region P2. When the number of liquid crystal domain regions that form different liquid crystal domains D3 and D4 is Nb, Na is 1 and Nb is 2.

Pixels defined by the pixel electrodes 124 are arranged at a predetermined pitch in the row direction and the column direction. In the following description, the pitch in the row direction of the pixels is also referred to as pitch P. The length in the row direction of one pixel is the pixel adjacent to the pixel electrode of the target pixel on the right side along the row direction from the intermediate line between the pixel electrode of the target pixel and the pixel electrode adjacent to the left side along the row direction. The pitch P is, for example, the length to the intermediate line with the electrode. For example, the edge 124s1 and the edge 124s3 of the pixel electrode 124 of the pixel adjacent in the row direction from the intersection of the edge 124s1 and the edge 124s3 of the pixel electrode 124 of a certain pixel. It corresponds to the distance to the intersection with. When one color is expressed by three pixels that display red, green, and blue, it is preferable that the aspect ratio of the three pixels is approximately 1: 1. In this case, the pitch P and the length h _a of one pixel, and h _b, satisfy the relationship of _{3 × P = h a + h} b.

Here, the length of the component projected on the pixel pitch P in the direction F2 is pa, and the length of the component projected on the pixel pitch P in the direction F1 is pb. In the following description, the width of the first partial electrode 124a along the direction F2 orthogonal to the direction F1 in the pixel electrode 124 is defined as Wa, and the second partial electrode along the direction F1 orthogonal to the direction F2 in the pixel electrode 124. The width of 124b is Wb. Further, the interval between adjacent first partial electrodes 124a is E1, and the interval between adjacent second partial electrodes 124b is E2. 2 to 4, when the edge 124s1 is continuous with the edge 124s3 and the edge 124s2 is continuous with the edge 124s4, the intervals E1 and E2 have a relationship of θ = tan ⁻¹ (E1 / E2). Satisfies.

  The length pa corresponds to the unit length along the second direction F2 of the arranged first pixel region P1, and the length pb is the first direction of the arranged second pixel region P2. This corresponds to the unit length along F1. The length pa is equal to the sum of the width Wa of the first partial electrode 124a and the interval E1, and similarly the length pb is equal to the sum of the width Wb of the second partial electrode 124b and the interval E2.

  The inventor of the present application shifts the angle formed between each of the directions F1 and F2 in which the first and second partial electrodes 124a and 124b extend and the x direction from 45 ° and projects the lengths pa and pb of the pixel pitch P. It was found that the liquid crystal domains D1 to D4 that suppress the decrease in the response speed and the aperture ratio can be formed at various pixel pitches P by differentiating.

  Here, the relationship between the lengths pa and pb and the pixel pitch P is expressed as follows.

pa = P × sin θ
pb = P × cos θ
The pixel pitch P satisfies the relationship P = √ (pa ² + pb ² ).

  The relationship between the widths Wa and Wb of the first and second partial electrodes 124a and the pixel pitch P is expressed as follows.

Wa + E1 = P × sin θ
Wb + E2 = P × cos θ

The relationship between the lengths pa and pb and the display characteristics will be described below. The length pa is pa = W1 + La + W2 + E1
It is expressed. Here, W1 and W2 indicate the widths of the liquid crystal domain regions R1 and R2, respectively, and La indicates the width of the rib 140a.

The length pb is pb = W3α + Lb1 + W3β + Sb + W4α + Lb2 + W4β + E2
It is expressed. Here, Lb1 and Lb2 indicate the widths of the ribs 140b1 and 140b2, respectively, and Sb indicates the width of the slit 120b. W3α, W3β, W4α and W4β indicate the widths of the liquid crystal domain regions R3α, R3β, R4α and R4β, respectively. The length pb is larger than the length pa, the interval E2 is larger than the interval E1, and the width Wb is larger than the width Wa.

  The shape of the rib 140a is a belt-like shape, and its long side extends in the direction F1. The width La of the rib 140a corresponds to the distance between the two long sides of the rib 140a. Further, the ribs 140b1 and 140b2 have a band shape, and the long sides thereof extend in the direction F2. The widths Lb1 and Lb2 of the ribs 140b1 and 140b2 correspond to the distance between the long sides of the ribs 140b1 and 140b2. Here, the widths La, Lb1, and Lb2 of the ribs 140a, 140b1, and 140b2 are 11 μm, respectively. If the widths La, Lb1, and Lb2 of the ribs 140a, 140b1, and 140b2 are too large, the aperture ratio decreases. Further, it is difficult to make it smaller than this in manufacturing.

  Moreover, the shape of the slit 120b is also a belt-like shape, and if the width Sb of the slit 120b is too large, the aperture ratio decreases. On the other hand, if the width Sb of the slit 120b is too small, the alignment is not sufficiently regulated, resulting in a decrease in transmittance. In this way, the display quality is degraded if the width Sb of the slit 120b is too large or too small. Here, the width Sb of the slit 120b is set to 9 μm.

  Further, as described above, the oblique electric field due to the edges 124 s 1 to 124 s 4 of the pixel electrode 124 also contributes to the alignment of the liquid crystal molecules 162. When the interval E1 between the adjacent first partial electrodes 124a and the interval E2 between the adjacent second partial electrodes 124b are too large, the aperture ratio decreases. On the other hand, if the distances E1 and E2 are too small, the alignment is not sufficiently regulated, resulting in a decrease in transmittance. In this way, the display quality is lowered if the intervals E1 and E2 are too large or too small. Here, the intervals E1 and E2 between the adjacent first and second partial electrodes 124a are each 6 μm. The manufacturing variation in the interval between the first and second partial electrodes 124a is ± 0.75 μm. In general, voltages having different polarities are applied to adjacent pixel electrodes, and a stronger alignment regulating force is exerted than in the vicinity of the slits, so that the interval between the pixel electrodes can be made smaller than the width of the slits.

  2 to 4, the edge 124s1 is continuous with the edge 124s3 and the edge 124s2 is continuous with the edge 124s4. In this case, however, the edge 124s1 and the edge 124s3 are connected and the edge 124s2 and the edge are connected. At least one of the connections with 124s4 is made through another edge parallel to the x direction.

  Next, the widths W1, W2, W3α, W3β, W4α and W4β of the liquid crystal domain regions R1, R2, R3α, R3β, R4α and R4β will be examined. The width of the liquid crystal domain region corresponds to the distance between the long sides of the parallelogram-shaped liquid crystal domain region, and the pixel alignment regulating structure 120D and the opposing alignment regulating structure when viewed from the normal direction of the display screen It corresponds to the length between the body 140D.

  FIG. 5 shows the relationship between the width W of the liquid crystal domain region and the transmittance. Here, the transmittance is normalized assuming that the transmittance when the width W is 13.5 μm is 1.0. As shown in FIG. 5, the transmittance increases as the width of the liquid crystal domain region increases. Note that when the width W exceeds about 18 μm, the inclination becomes small and becomes saturated at a transmittance ratio of about 1.12.

  FIG. 6 shows the relationship between the width W of the liquid crystal domain region and the response time. Here, the response time from the 10th gradation level to the 255th gradation level (maximum gradation level) is shown, and the response speed is larger as the response time is shorter.

  As can be understood from FIG. 6, the longer the width of the liquid crystal domain region, the longer the response time and the lower the response speed. Here, if the limit of the response time is 2 frames (33.4 msec), the maximum value of the width W of the liquid crystal domain region is 23.5 μm. In consideration of some deviation, the width of the liquid crystal domain region is preferably 23.0 μm or less.

  Strictly speaking, the transmittance and response speed are influenced not only by the width W of the liquid crystal domain region but also by other parameters such as the thickness of the liquid crystal material and the liquid crystal layer, but the width W of the liquid crystal domain region is most dominant. Parameters.

  As described above, the width of the liquid crystal domain region is preferably within a predetermined range from the viewpoint of transmittance and response speed (response time). For example, the width of the liquid crystal domain region is preferably in the range of 18.0 μm or more and less than 23.5 μm. The width of the liquid crystal domain region is more preferably 23.0 μm or less.

  Ideally, from the viewpoint of uniform response speed of each liquid crystal domain region, the widths W1, W2, W3α, W3β, W4α and W4β of the liquid crystal domain regions R1, R2, R3α, R3β, R4α and R4β Are preferably equal to each other. Here, it is assumed that the width W1 of the liquid crystal domain region R1 is equal to the width W2 of the liquid crystal domain region R2, and W1 = W2 = Wx. Further, it is assumed that the widths W3α, W3β, W4α and W4β of the liquid crystal domain regions R3α, R3β, R4α and R4β are equal to each other, and W3α = W3β = W4α = W4β = Wy.

As described above, pa = Wa + E1 and pb = Wb + E2. The lengths pa and pb are set so as to form liquid crystal domains D1 to D4 that satisfy P = √ (pa ² + pb ² ) and suppress a decrease in response speed and aperture ratio. For this reason, by setting appropriate lengths pa and pb with respect to the pixel pitch P, it is possible to suppress a decrease in response speed and aperture ratio. In this case, the angle θ formed by the first direction F1 and the x direction is set so as to satisfy θ = tan ⁻¹ (pb / pa) (excluding θ = 45 °). In this way, the liquid crystal display device 100 can suppress a decrease in response speed and aperture ratio in various sizes.

  Hereinafter, the advantages of the liquid crystal display device 100 of this embodiment compared to the liquid crystal display device of Comparative Example 1 and the liquid crystal display device of Comparative Example 2 will be described. First, a liquid crystal display device 500 of Comparative Example 1 will be described with reference to FIG. FIG. 7A shows a schematic diagram of the liquid crystal display device 500, and FIG. 7B shows a pixel structure of the liquid crystal display device 500. FIG.

  In the liquid crystal display device 500 of Comparative Example 1, the first partial electrode 524a of the pixel electrode 524 extends in the 45 ° direction with respect to the x direction, and the second partial electrode 524b extends in the 45 ° direction with respect to the x direction. . The pixel electrode 524 has a symmetrical shape in the x direction. A rib 540a is provided on the counter substrate 540 side corresponding to the first partial electrode 524a, and a rib 540b is provided on the counter substrate 540 side corresponding to the second partial electrode 524b. It has been.

  Next, a liquid crystal display device 600 of Comparative Example 2 will be described with reference to FIG. FIG. 8A shows a schematic diagram of the liquid crystal display device 600, and FIG. 8B shows a pixel structure of the liquid crystal display device 600.

  In the liquid crystal display device 600 of Comparative Example 2, the first partial electrode 624a of the pixel electrode 624 extends in the 45 ° direction with respect to the x direction, and the second partial electrode 624b extends in the 45 ° direction with respect to the x direction. . The pixel electrode 624 has a symmetrical shape in the x direction. Two ribs 640a1 and 640a2 are provided corresponding to the first partial electrode 624a on the liquid crystal layer 660 side of the counter substrate 640, and two ribs 640b1 and 640b2 are provided corresponding to the second partial electrode 624b. Yes. Further, on the liquid crystal layer 660 side of the active matrix substrate 620, a slit 620a is provided at a corresponding position between the two ribs 640a1 and 640a2, and a slit 620b is provided at a corresponding position between the two ribs 640b1 and 640b2. Is provided.

  Here, in the liquid crystal display device 500 of the comparative example 1 and the liquid crystal display device 600 of the comparative example 2, the pixel pitch and the size of the liquid crystal display device which suppress the decrease in the response speed and the aperture ratio will be described. Note that in both the liquid crystal display devices 500 and 600 of Comparative Examples 1 and 2, since the pixels have a symmetric structure with respect to the x direction, only the configuration of the first pixel region P1 is considered.

  In the liquid crystal display device 500, the width W of the liquid crystal domain region is 23 μm, the width L of the rib 540a is 11 μm, the width W of the first partial electrode 524a is 57 μm, and the adjacent first partial electrodes 524a The interval E is 6 μm. In this case, the length pa is 63 μm and the pixel pitch P is 69 μm. As described above, the width W of 23 μm corresponds to the pitch P of 69 μm.

  The pitch P of 69 μm corresponds to approximately 23 inches in the full high-definition standard (FHD) with a resolution of 1920 × 1080, and corresponds to approximately 17 inches in the high-definition standard (WXGA) with a resolution of 1366 × 768. In the following description of this specification, WXGA may be referred to as “WX”.

  In the liquid crystal display device 600, the width W of the liquid crystal domain region is 23 μm, the width L of the ribs 640a1 and 640a2 is 11 μm, and the width S of the slit 620a is 9 μm. The width W of the first partial electrode 624a is 123 μm, and the interval E between the adjacent first partial electrodes 624a is 6 μm. In this case, the length pa is 129 μm, and the pixel pitch P is 182 μm. This corresponds to about 48 inches in FHD or about 34 inches in WX.

  Thus, if the liquid crystal display device 500 of the comparative example 1 and the liquid crystal display device 600 of the comparative example 2 are also of a specific size, it is possible to suppress a decrease in response speed and aperture ratio. However, the liquid crystal display device 500 of the comparative example 1 and the liquid crystal display device 600 of the comparative example 2 of different sizes cannot suppress a decrease in response speed and aperture ratio.

  Here, as an example, the configurations of the liquid crystal display device 500 of comparative example 1 and the liquid crystal display device 600 of comparative example 2 having an FHD size of about 33 inches are examined. In this case, the pitch of the pixels P is about 126 μm, and the length pa is 89 μm. A pitch P of 126 μm corresponds to about 23 inches in WX.

  Here, values other than the width W of the liquid crystal domain region (that is, the width of the rib, the width of the slit, and the interval between the partial electrodes) are set in the same manner as described above, and the width W of the liquid crystal domain region is adjusted. Thus, by not changing the values of the rib width, slit width, and partial electrode spacing, it is possible to suppress a decrease in transmittance. In the liquid crystal display device 500 of Comparative Example 1, when the interval E between the adjacent first partial electrodes 524a is 6 μm and the width L of the rib 540a is 11 μm, the width W of the liquid crystal domain region is 36 μm. Thus, when the width W is long, the response speed is lowered.

  Also in the liquid crystal display device 600 of Comparative Example 2, if the interval E between the adjacent first partial electrodes 624a is 6 μm, the width L of the ribs 640a1 and 640a2 is 11 μm, and the width S of the slit 620a is 9 μm, The width W is 13 μm. Thus, when the width W is short, the aperture ratio (transmittance) decreases.

  On the other hand, in the liquid crystal display device 100 of the present embodiment, the response speed and the aperture ratio of the liquid crystal display devices 500 and 600 of Comparative Examples 1 and 2 are reduced even if the response speed and the aperture ratio are reduced. The decrease can be suppressed. For example, consider the configuration of the liquid crystal display device 100 of the present embodiment having an FHD size of about 33 inches. In this case, the size of the display area is about 73 cm × 41 cm. In general, a liquid crystal display device performs display with three pixels of red, blue, and green arranged in a row direction. In this case, the pitch of one pixel is about 126 μm × 380 μm. Thus, the pitch of one pixel is determined according to the number of pixels and the size of the liquid crystal display device. The aspect ratio of the pitch of one pixel is approximately 3: 1, and the aspect ratio of one display unit including three pixels displaying red, blue, and green is approximately 1: 1.

  Again referring to FIGS. Here, an angle θ is set to 30 ° in a pixel having a pitch P of about 126 μm. In this case, as described above, the length pa is 63 μm (= 126 × sin 30 °), and the length pb is 109 μm (= 126 × cos 30 °).

  Here, the configuration of the first pixel region P1 will be considered. As described above, the length pa is 63 μm. The width La of the rib 140a is 11 μm, and the interval E1 between the adjacent first partial electrodes 124a is 6 μm. Further, assuming that the width W1 of the first liquid crystal domain region R1 is equal to the width W2 of the second liquid crystal domain region R2, and these widths W1 and W2 are denoted as Wx, Wx is 23 μm. Thus, the width Wx of the first and second liquid crystal domain regions R1 and R2 can be set within a predetermined range.

  Further, the configuration of the second pixel region P2 will be examined. As described above, the length pb is 109 μm. In addition, the widths Lb1 and Lb2 of the ribs 140b1 and 140b2 are 11 μm, the width Sb of the slit 120b is 9 μm, and the interval E2 between the adjacent second partial electrodes 124b is 6 μm.

  Further, assuming that the widths W3α, W3β, W4α, and W4β of the liquid crystal domain regions R3α, R3β, R4α, and R4β are equal to each other, and these widths W3α, W3β, W4α, and W4β are denoted as Wy, Wy is 18 μm. In this way, the width Wy of the liquid crystal domain regions R3α, R3β, R4α, and R4β can be set within a range that suppresses the decrease in response speed and aperture ratio.

  In the liquid crystal display device 100 of the present embodiment, the pitch F of a certain pixel changed as the angles of the directions F1 and F2 of the first and second partial electrodes 124a and 124b with respect to the x direction differed from 45 °. For each of the lengths pa and pb, by forming the liquid crystal domains D1 to D4 that can suppress the decrease in the response speed and the aperture ratio, the display quality of the configurations of the liquid crystal display devices 500 and 600 of Comparative Examples 1 and 2 is reduced. Even with the size, a reduction in display quality can be suppressed. Further, by changing the angle θ with respect to the lengths pa and pb capable of forming the liquid crystal domains D1 to D4 that can suppress the decrease in the response speed and the aperture ratio, the pixel pitch P can be changed. The degree of freedom can be increased.

In the above description, the width Wx of the liquid crystal domain regions R1 and R2 corresponding to the first pixel region P1 is different from the width Wy of the liquid crystal domain regions R3α, R3β, R4α, and R4β corresponding to the second pixel region P2. However, the width Wx may be equal to the width Wy. For example, Wx = Wy = 23 μm may be set. As described above, the width of the ribs 140a, 140b1, and 140b2 is 11 μm, the width of the slit 120b is 9 μm, the interval E1 between the adjacent first partial electrodes 124a is 6 μm, and the interval E2 between the adjacent second partial electrodes 124b is set. Assuming 6 μm, the lengths pa and pb are 63 μm and 129 μm, respectively. In this case, θ = 26 ° (= tan ⁻¹ (63/129)) and the pixel pitch P is 144 μm (= √ (63 ² +129 ² )). This corresponds to about 37 inches in FHD or about 26 inches in WX.

  In the above description, the number (Na) of the liquid crystal domain regions of the liquid crystal domains D1 and D2 corresponding to the first partial electrode 124a is 1, and the liquid crystal domains D3 and D4 corresponding to the second partial electrode 124b. Although the number of domain regions (Nb) was 2, respectively, the present invention is not limited to this. The number (Na) of the liquid crystal domain regions of the liquid crystal domains D1 and D2 may not be one. Further, the number (Nb) of the liquid crystal domain regions of the liquid crystal domains D3 and D4 may not be two.

  For example, the number of liquid crystal domain regions D1 and D2 corresponding to the first partial electrode 124a is 1, and the number of liquid crystal domain regions D3 and D4 corresponding to the second partial electrode 124b is 3 respectively. There may be. Alternatively, the number of liquid crystal domain regions in the liquid crystal domains D1 and D2 may be two, and the number of liquid crystal domain regions in the liquid crystal domains D3 and D4 may be three. Here, Na <Nb is set for the purpose of avoiding an excessively complicated description.

  In the configuration of the liquid crystal display device 100, the angle θ and the pixel pitch P may be set on the basis of the lengths pa and pb that realize the suppression of the decrease in the response speed and the aperture ratio. For example, the liquid crystal domain D3, The number of liquid crystal domain regions corresponding to D4 may be an integer multiple of the number of liquid crystal domain regions corresponding to liquid crystal domains D1 and D2. Here, in order to simplify the explanation, the width of the slits and ribs and the interval between the adjacent partial electrodes are ignored, and the width Wx of the liquid crystal domain region corresponding to the liquid crystal domains D1 and D2 and the liquid crystal domains D3 and D4 are supported. If the widths Wy of the liquid crystal domain regions are equal to each other, the ratio of the length pa to the length pb is also an integral multiple.

For example, the ratio of the length pa and length pb is 1: to achieve a 2 pixels serving, θ = 27 ° (= tan -1 (1/2)) , and the pitch P of the pixels to the length pa is √5 times. Further, when realizing a pixel in which the ratio of the length pa to the length pb is 1: 3, θ = 18 ° (= tan ⁻¹ (1/3)), and the pixel pitch P with respect to the length pa is √10 times. As understood from the above, the length pb and the pixel pitch P increase as θ decreases even if the length pa is constant. Further, based on the ratio of the lengths pa and pb, the angles of the directions F1 and F2 with respect to the x direction change, and the pixel pitch and the accompanying size of the liquid crystal display device change.

  Here, with reference to FIG. 9 to FIG. 11, advantages of the liquid crystal display device 100 of this embodiment compared to the liquid crystal display device 700 of Comparative Example 3 and the liquid crystal display device 800 of Comparative Example 4 will be described.

  First, a liquid crystal display device 700 of Comparative Example 3 will be described with reference to FIG. In the liquid crystal display device 700 of Comparative Example 3, the first and second partial electrodes 724a and 724b of the pixel electrode 724 extend in the 45 ° direction with respect to the x direction, and the pixel electrode 724 has a symmetrical shape in the x direction. This is different from the liquid crystal display device 100 of this embodiment. In the liquid crystal display device 700 of Comparative Example 3, when the pixel pitch P changes, the width W of the liquid crystal domain regions R1 to R4 is constant, and the width L of the ribs 740a and 740b increases as the pixel pitch P increases. And / or the interval E between the pixel electrodes 724 is increased. However, when the width L of 740a and 740b becomes larger than a certain value, another rib and slit are provided, and the number of liquid crystal domain regions corresponding to each of the liquid crystal domains D1 and D2 corresponding to the first partial electrode 724a is increased. To increase.

  Next, a liquid crystal display device 800 of Comparative Example 4 will be described with reference to FIG. The liquid crystal display device 800 of Comparative Example 4 differs from the liquid crystal display device 100 of the present embodiment in that the pixel electrode 824 is rectangular. In the liquid crystal display device 800 of Comparative Example 4, ribs 840a and 840b are provided as the opposing alignment regulating structure 840D, and the slit 820a and the corresponding pixel alignment regulating structure 820D are provided between the ribs 840a and 840b. 820b is provided. In the liquid crystal display device 800, even if the pixel pitch P changes, the ratio of the area of the slits 820a and 820b and the ribs 840a and 840b to the area of the pixel electrode 824 is substantially constant, and the liquid crystal domain increases as the pixel pitch P increases. Area (area of the opening region) increases.

  FIG. 11 is a graph showing a change in transmittance with respect to the pixel pitch. Here, the transmittance means the ratio of the amount of light transmitted through the liquid crystal layer, the color filter layer and the two polarizing plates of the liquid crystal display device to the amount of light immediately before entering the polarizing plate on the back side. is doing. In FIG. 11, Na represents the number of liquid crystal domain regions that form the liquid crystal domain D1 and the liquid crystal domain D2 in (Na, Nb), and Nb forms the liquid crystal domain D3 and the liquid crystal domain D4. The number of each liquid crystal domain region is shown.

  In the liquid crystal display device 700 of the comparative example 3, when the pixel pitch P is 89 μm, the number of liquid crystal domain regions that form the liquid crystal domains D1 and D2 corresponding to the first partial electrode 724a is 1, respectively. The number of liquid crystal domain regions that form the liquid crystal domains D3 and D4 corresponding to the electrode 724b is 1 respectively. Note that the pitch P of 89 μm corresponds to about 17 inches of WXGA. The length pa is 63 μm. In this case, if the interval E between the adjacent first partial electrodes 724a is 6 μm and the width of the slit 740a is 11 μm, the width W of the liquid crystal domain region is 23 μm. The sum of the widths of the liquid crystal domain regions with respect to the length pa is 46/63, which corresponds to a transmittance of about 4.3%.

  When the pixel pitch P is 182 μm, the number of liquid crystal domain regions D1 and D2 corresponding to the first partial electrode 724a is 2, and the liquid crystal domains D3 and D4 corresponding to the second partial electrode 724b are respectively. The number of liquid crystal domain regions forming each is 2. The pitch P of 182 μm corresponds to WXGA of about 34 inches. In this case, the lengths pa and pb are 129 μm, the width W of the liquid crystal domain region is 23 μm, the interval E between the adjacent first partial electrodes 724a is 6 μm, and the total width of the slits and ribs is 31 μm. . The sum of the widths of the liquid crystal domain regions with respect to the length pa is 92/129, which corresponds to a transmittance of about 5.4%.

  In addition, when the pixel pitch P is 276 μm corresponding to about 51 inches of WXGA, the number of liquid crystal domain regions D1 and D2 corresponding to the first partial electrode 724a is 3, respectively. The number of liquid crystal domain regions that form the liquid crystal domains D3 and D4 corresponding to the partial electrode 724b is three. A pitch P of 276 μm corresponds to about 51 inches of WXGA. In this case, the lengths pa and pb are 195 μm, the width W of the liquid crystal domain region is 23 μm, the interval E between the adjacent first partial electrodes 724a is 6 μm, and the total width of the slits and ribs is 51 μm. . The sum of the width of the liquid crystal domain region with respect to the length pa is 138/195, which corresponds to a transmittance of about 5.8%. In the liquid crystal display device 700 of Comparative Example 3, the ratio indicating the sum of the widths of the liquid crystal domain regions with respect to the length pa is substantially equal, but the transmittance increases as the pixel pitch P increases.

  Thus, in the configuration of the liquid crystal display device 700, when the pixel pitch is a specific size, a high transmittance (aperture ratio) can be realized while suppressing a decrease in response speed. However, when the pixel pitch is a different size, at least one of the response speed and the aperture ratio decreases.

  For example, in the liquid crystal display device 700 of the comparative example 3, when the pixel pitch P is 126 μm corresponding to about 23 inches of WXGA, the liquid crystal domain region forming the liquid crystal domains D1 and D2 corresponding to the first partial electrode 724a Is 1, and the number of liquid crystal domain regions forming the liquid crystal domains D3 and D4 corresponding to the second partial electrode 724b is 1 respectively. In this case, the length pa is 89 μm. Here, in order to suppress a decrease in response speed, if the width W of the liquid crystal domain region is 23 μm and the interval E between the first partial electrodes 724a is 6 μm, the width of the rib 740a is 37 μm. The sum of the widths of the liquid crystal domain regions with respect to the length pa is 46/89, and the transmittance is reduced to about 3.6%.

  Similarly, when the pixel pitch P is 214 μm corresponding to about 56 inches of FHD, the number of liquid crystal domain regions D1 and D2 corresponding to the first partial electrode 724a is two, respectively. The number of liquid crystal domain regions that form the liquid crystal domains D3 and D4 corresponding to the two-part electrode 724b is two. In this case, the lengths pa and pb are 151 μm. Here, in order to suppress a decrease in response speed, if the width W of the liquid crystal domain region is 23 μm and the interval E between the first partial electrodes 724a is 6 μm, the total width of the ribs and slits is 53 μm. The sum of the widths of the liquid crystal domain regions with respect to the length pa is 92/151, and the transmittance is reduced to about 4.8%. As described above, in the configuration of the liquid crystal display device 700, when the pixel pitch is a specific size, it is possible to suppress a decrease in the response speed and the aperture ratio, but when the pixel pitch is a different size, the response speed is reduced. If the decrease of the aperture is suppressed, the aperture ratio (transmittance) is decreased.

  In the liquid crystal display device 800 of Comparative Example 4, the transmittance (aperture ratio) increases as the pixel pitch P increases. In the liquid crystal display device 800, since the pixel electrode 824 is rectangular, the liquid crystal domain region R and its width W can be set to values corresponding to the maximum transmittance regardless of the pixel pitch P. However, as described above with reference to Patent Document 1, there is a region where the alignment regulation direction by the edge of the pixel and the alignment regulation direction by the rib are mismatched, and alignment disorder occurs. Thus, the disordered region is about 10% of the opening region corresponding to the difference between the area of the pixel electrode 824 and the areas of the slits 820a and 820b and the ribs 840a and 840b.

  On the other hand, in the liquid crystal display device 100 of the present embodiment, a high transmittance can be realized even at a pixel pitch P at which the transmittance decreases in the liquid crystal display device 700 of the comparative example 3. Further, in the liquid crystal display device 100, the occurrence of alignment disorder is suppressed, and a higher transmittance than that of the liquid crystal display device 800 of Comparative Example 4 can be realized.

  Although the width W1 of the first liquid crystal domain region R1 is equal to the width W2 of the second liquid crystal domain region R2, the present invention is not limited to this. If the widths W1 and W2 of the first and second liquid crystal domain regions R1 and R2 are within a predetermined range, the widths W1 and W2 of the first and second liquid crystal domain regions R1 and R2 may be different.

  Similarly, in the above description, the widths W3α, W3β, W4α, and W4β of the liquid crystal domain regions R3α, R3β, R4α, and R4β are equal to each other, but the present invention is not limited to this. The widths W3α, W3β, W4α and W4β may be different as long as they are within a predetermined range.

For example, when Na = 1 and Nb = 2, pa is 53 μm to 63 μm, and pb is 109 μm to 129 μm. In this case, the angle θ is 22 ° (= tan ⁻¹ (53/129)) ≦ θ ≦ 30 ° (= tan ⁻¹ (63/109)), and the pixel pitch P is 121 (= √ (53 ² +109 ² )) ≦ P ≦ 143 (= √ (63 ² +129 ² )).

For example, when Na = 1 and Nb = 3, pa is 53 μm to 63 μm, and pb is 165 μm to 195 μm. In this case, the angle θ is 15 ° (= tan ⁻¹ (53/195)) ≦ θ ≦ 21 ° (= tan ⁻¹ (63/165)), and the pixel pitch P is 173 (= √ (53 ² +165 ² )) ≦ P ≦ 204 (= √ (63 ² +195 ² )).

Alternatively, when Na = 2 and Nb = 3, pa is 109 μm to 129 μm and pb is 165 μm to 195 μm. In this case, the angle θ is 28 ° (= tan ⁻¹ (109/195)) ≦ θ ≦ 38 ° (= tan ⁻¹ (129/165)), and the pixel pitch P is 198 (= √ (109 ² +165 ² )) ≦ P ≦ 234 (= √ (129 ² +195 ² )).

For example, when Na = 3 and Nb = 4, pa is 165 μm to 195 μm, and pb is 221 μm to 261 μm. In this case, the angle θ is 32 ° (= tan ⁻¹ (165/261)) ≦ θ ≦ 41 ° (= tan ⁻¹ (195/221)), and the pixel pitch P is 276 (= √ (165 ² +221 ² )) ≦ P ≦ 325 (= √ (195 ² +261 ² )).

  In the above description, the number (Nb) of the liquid crystal domain regions of the liquid crystal domains D3 and D4 corresponding to the second partial electrode 124b provided on the lower side (−y direction) of the pixel electrode 124 is the pixel electrode 124. Is larger than the number (Na) of the liquid crystal domain regions of the liquid crystal domains D1 and D2 corresponding to the first partial electrode 124a provided on the upper side (+ y direction), but the present invention is not limited to this. Na may be larger than Nb.

  In the above description, the number (Nb) of the liquid crystal domains D3 and D4 corresponding to the second partial electrode is equal to the number of liquid crystal domains D1 and D2 corresponding to the first partial electrode 124a. Although it differs from the number of regions (Na), the present invention is not limited to this. The number (Nb) of the respective liquid crystal domains D3 and D4 corresponding to the second partial electrode is equal to the respective liquid crystal domain (Na) of the liquid crystal domains D1 and D2 corresponding to the first partial electrode 124a. Also good.

For example, when Na = Nb = 1, pa and pb are 53 μm to 63 μm (however, pa = pb is excluded). In this case, the angle θ is 40 ° (= tan ⁻¹ (53/63)) ≦ θ ≦ 50 ° (= tan ⁻¹ (63/53)) (however, excluding θ = 45 °), and the pixel The pitch P is 74 (= √ (53 ² +53 ² )) <P <89 (= √ (63 ² +63 ² )).

For example, when Na = Nb = 2, pa and pb are 109 μm to 129 μm (however, pa = pb is excluded). In this case, the angle θ is 40 ° (= tan ⁻¹ (109/129)) ≦ θ ≦ 50 ° (= tan ⁻¹ (129/109)) (except θ = 45 °), and the pixel The pitch P is 154 (= √ (109 ² +109 ² )) <P <182 (= √ (129 ² +129 ² )).

When Na = Nb = 3, pa and pb are 165 μm to 195 μm (however, pa = pb is excluded). In this case, the angle θ is 40 ° (= tan ⁻¹ (165/195)) ≦ θ ≦ 50 ° (= tan ⁻¹ (195/165)) (except θ = 45 °), and the pixel The pitch P is 233 (= √ (165 ² +165 ² )) <P <276 (= √ (195 ² +195 ² )).

  In the above description, the pixel electrode 124 is composed of one first partial electrode 124a and one second partial electrode 124b, but the present invention is not limited to this. As shown in FIG. 12, the pixel electrode 124 may include one first partial electrode 124a and two second partial electrodes 124b1 and 124b2. In this case, the first partial electrode 124a is provided between the second partial electrode 124b1 and the second partial electrode 124b2.

  As described above, when the lengths pa and pb are different from each other, the widths Wa and Wb of the first and second partial electrodes 124a may be different from each other. However, since the widths Wa and Wb are equal to each other, characteristics such as response characteristics can be made uniform.

  In the above description, the first partial electrode 124a is continuous with the second partial electrode 124b, but the present invention is not limited to this. The first partial electrode 124a may be provided separately from the second partial electrode 124b.

  In the above description, the width of the rib, the width of the slit, and the interval between the adjacent partial electrodes are fixed values (specifically, 11 μm, 9 μm, and 6 μm). It is not limited. Each of the width of the rib, the width of the slit, and the interval between the adjacent partial electrodes may be within a predetermined range.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display device which suppressed the display quality fall with respect to the pixel of various pitches can be provided.

1 is a schematic view of an embodiment of a liquid crystal display device according to the present invention. FIG. 2 is a schematic plan view illustrating a pixel structure of the liquid crystal display device illustrated in FIG. 1. FIG. 2 is a schematic plan view illustrating a pixel structure of the liquid crystal display device illustrated in FIG. 1. FIG. 2 is a schematic plan view illustrating a pixel structure of the liquid crystal display device illustrated in FIG. 1. It is a graph which shows the relationship between the width | variety of a liquid crystal domain area | region, and the transmittance | permeability. It is a graph which shows the relationship between the width | variety of a liquid crystal domain area | region, and response time. (A) is a schematic diagram which shows the liquid crystal display device of the comparative example 1, (b) is a schematic top view which shows the pixel structure of the liquid crystal display device of the comparative example 1. (A) is a schematic diagram which shows the liquid crystal display device of the comparative example 2, (b) is a schematic top view which shows the pixel structure of the liquid crystal display device of the comparative example 2. 10 is a schematic plan view showing a liquid crystal display device of Comparative Example 3. FIG. 10 is a schematic plan view showing a liquid crystal display device of Comparative Example 4. FIG. It is a graph which shows the change of the transmittance | permeability with respect to the pitch of a pixel. 1 is a schematic view of an embodiment of a liquid crystal display device according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Liquid crystal display device 120 Active matrix substrate 122 Insulating substrate 124 Pixel electrode 124a 1st partial electrode 124b 2nd partial electrode 140 Opposite substrate 142 Insulating substrate 144 Counter electrode 160 Liquid crystal layer 162 Liquid crystal molecule

Claims (11)

An active matrix substrate having a plurality of pixel electrodes each defining a pixel, the pixel electrodes being arranged in a matrix of a plurality of rows and a plurality of columns;
A counter substrate having a counter electrode;
A liquid crystal display device comprising a vertical alignment type liquid crystal layer provided between the active matrix substrate and the counter substrate,
Each of the plurality of pixel electrodes has a first partial electrode and a second partial electrode,
The first partial electrode has a first edge and a second edge extending parallel to a first direction oblique to a row direction defining a direction of the plurality of rows in which the plurality of pixel electrodes are arranged. And
The two partial electrodes have a third edge and a fourth edge extending in parallel with a second direction orthogonal to the first direction,
The counter substrate further includes a linear first counter alignment regulating structure provided on the liquid crystal layer side and a linear second counter alignment regulating structure provided on the liquid crystal layer side. ,
The first opposing alignment regulating structure extends in parallel with the first direction so as to face the first partial electrodes of the plurality of pixel electrodes,
The second opposing alignment regulating structure extends in parallel with the second direction so as to face the second partial electrodes of the plurality of pixel electrodes,
The angle formed by the first direction and the row direction is different from the angle formed by the second direction and the row direction, and the length of the component obtained by projecting the pitch of the pixels in the row direction in the first direction is A liquid crystal display device, wherein a pitch of the pixels in the row direction is different from a length of a component projected in the second direction.   2. The liquid crystal display device according to claim 1, wherein a width of the first partial electrode along a direction parallel to the second direction is different from a width of the second partial electrode along a direction parallel to the first direction. . The angle formed by the first direction and the row direction is smaller than the angle formed by the second direction and the row direction,
The length of a component obtained by projecting the pitch in the row direction of the pixel in the first direction is larger than the length of a component obtained by projecting the pitch in the row direction of the pixel in the second direction. The liquid crystal display device described. The liquid crystal layer includes a first liquid crystal domain and a second liquid crystal domain positioned between the first partial electrode and the counter electrode, and a third liquid crystal domain positioned between the second partial electrode and the counter electrode. And a fourth liquid crystal domain,
The first liquid crystal domain and the second liquid crystal domain have alignment azimuth components that are orthogonal to each other with respect to a first opposed alignment regulating structure that extends parallel to the first direction when a voltage is applied to at least the liquid crystal layer. Including liquid crystal molecules having
The third liquid crystal domain and the fourth liquid crystal domain have alignment azimuth components that are orthogonal to each other with respect to a second opposing alignment regulating structure that extends parallel to the second direction when a voltage is applied to at least the liquid crystal layer. The liquid crystal display device according to claim 1, comprising liquid crystal molecules. The active matrix substrate includes a first pixel alignment regulating structure corresponding to the first partial electrode on the liquid crystal layer side and a second pixel alignment regulating structure corresponding to the second partial electrode on the liquid crystal layer side. In addition,
The first pixel alignment regulation structure includes the first edge and the second edge of the first partial electrode, and the second pixel alignment regulation structure includes the third edge of the second partial electrode and the second edge. Including the fourth edge,
Each of the first opposed orientation regulating structure and the second opposed orientation regulating structure includes at least one rib or slit,
The liquid crystal layer is
At least one first liquid crystal domain region in which the first liquid crystal domain is formed;
At least one second liquid crystal domain region in which the second liquid crystal domain is formed;
At least one third liquid crystal domain region in which the third liquid crystal domain is formed;
Having at least one fourth liquid crystal domain region in which the fourth liquid crystal domain is formed,
Each of the first liquid crystal domain region and the second liquid crystal domain region is defined between the first counter alignment restriction structure and the first pixel alignment restriction structure,
5. The liquid crystal according to claim 4, wherein each of the third liquid crystal domain region and the fourth liquid crystal domain region is defined between the second counter alignment regulating structure and the second pixel alignment regulating structure. Display device.   6. The liquid crystal display device according to claim 5, wherein widths of the first liquid crystal domain region, the second liquid crystal domain region, the third liquid crystal domain region, and the fourth liquid crystal domain region are within a predetermined range.   The width of each of the first liquid crystal domain region, the second liquid crystal domain region, the third liquid crystal domain region, and the fourth liquid crystal domain region is in a range of 18 μm or more and less than 23.5 μm. Liquid crystal display device. A first polarizing plate provided on the active matrix substrate;
A second polarizing plate provided on the counter substrate,
One of the first polarizing plate and the second polarizing plate has an intermediate direction between a column direction defining the direction of the plurality of columns in which the plurality of pixel electrodes are arranged and the row direction. And having a transmission axis shifted by an angle between the first direction and the row direction,
The other polarizing plate of the first polarizing plate and the second polarizing plate has a transmission axis that is shifted by an angle formed by the first direction and the row direction with respect to a direction orthogonal to the intermediate direction. The liquid crystal display device according to claim 1.   The first edge of the first partial electrode is continuous with the third edge of the second partial electrode, and the second edge of the first partial electrode is continuous with the fourth edge of the second partial electrode. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is a liquid crystal display device. At least one of the first opposed alignment regulating structure and the second opposed alignment regulating structure includes a plurality of ribs or slits arranged in parallel to each other,
Of the first pixel alignment restriction structure and the second pixel alignment restriction structure, the pixel alignment restriction structure corresponding to the at least one opposing alignment restriction structure faces between the plurality of ribs or slits. The liquid crystal display device according to claim 5, comprising a slit or a rib provided at a position.   8. The number of each of the first liquid crystal domain region and the second liquid crystal domain region is different from the number of each of the third liquid crystal domain region and the fourth liquid crystal domain region. Liquid crystal display device.

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