Liquid crystal display device

Abstract

To provide a VA-mode liquid crystal display device in which an alignment division structure is formed by defining a pretilt direction with an alignment film, and a display defect due to discontinuous points of liquid crystal alignment is suppressed.SOLUTION: A liquid crystal display device includes a first substrate including a pixel electrode and a first alignment film, a second substrate including a counter electrode and a second alignment film, and a liquid crystal layer of a vertical alignment type. Each pixel includes first to fourth liquid crystal domains in which reference alignment directions defined by the first and second alignment films are different from each other. The pixel electrode includes first to fourth slit formation regions corresponding to the first to fourth liquid crystal domains, and a border region existing between the second and third slit formation regions. The border region includes n (n is an integer of 3 or more) border slits extending substantially parallel to a pixel short-side direction, (n-1) first coupling parts each existing between the two adjacent border slits, and (n-2) depressed patterns each existing between the two adjacent first coupling parts.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device that includes a vertical alignment type liquid crystal layer and in which the pretilt direction of liquid crystal molecules is defined by an alignment film. [Background technology]

[0002] A multi-domain structure, which forms multiple liquid crystal domains in one pixel, is known as a method for improving the viewing angle characteristics of VA (Vertical Alignment) mode LCDs. In recent years, a 4D-RTN (Reverse Twisted Nematic) mode has been proposed as a method for forming a multi-domain structure.

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

[0004] Furthermore, in the liquid crystal display device of Patent Document 1, the pretilt direction determined by one of a pair of alignment films facing each other across a liquid crystal layer differs by approximately 90° from the pretilt direction determined by the other alignment film. Therefore, when a voltage is applied, the liquid crystal molecules assume a twisted alignment. As can be understood from the disclosure of Patent Document 1, in the 4D-RTN mode, four liquid crystal domains are typically arranged in two rows and two columns within a pixel.

[0005] Patent Document 2 also discloses a VA-mode liquid crystal display device in which a multi-domain structure is formed by defining a pretilt direction with alignment films. In the liquid crystal display device disclosed in Patent Document 2, the pretilt direction defined by one of a pair of alignment films is antiparallel to the pretilt direction defined by the other alignment film. Therefore, when a voltage is applied, the liquid crystal molecules do not assume a twisted alignment. The display mode disclosed in Patent Document 2 is called a 4D-ECB (Electrically Controlled Birefringence) mode.

[0006] In the liquid crystal display device of Patent Document 2, four liquid crystal domains are arranged in a 4-row, 1-column configuration within a pixel. Fig. 34 shows the domain arrangement disclosed in Patent Document 2. A pixel 900P shown in Fig. 34 has four liquid crystal domains A, B, C, and D. In Fig. 34, the directors (reference alignment directions) of each liquid crystal domain are schematically shown as pins. If the display surface is likened to a clock face, and the 3 o'clock direction is defined as an azimuth angle of 0° and the counterclockwise direction is defined as positive, the directors of liquid crystal domains A, B, C, and D are oriented in the 315° direction, 45° direction, 225° direction, and 135° direction, respectively.

[0007] In the pixel 900P, the liquid crystal domains A, B, C, and D are arranged in this order from top to bottom (i.e., along the longitudinal direction of the pixel). The director orientations of the liquid crystal domains A and B differ by 90°. The director orientations of the liquid crystal domains B and C differ by 180°, and the director orientations of the liquid crystal domains C and D differ by 90°.

[0008] 35 shows a pixel electrode 911 disclosed in Patent Document 2. The pixel electrode 911 has a first pixel electrode portion 911P1 corresponding to the liquid crystal domains A and B and a second pixel electrode portion 911P2 corresponding to the liquid crystal domains C and D.

[0009] The first pixel electrode portion 911P1 includes a first slit formation region 911R1 corresponding to the liquid crystal domain A and a second slit formation region 911R2 corresponding to the liquid crystal domain B. The first slit formation region 911R1 has a plurality of slits 911s1 formed therein, each extending parallel to the director of the liquid crystal domain A. The second slit formation region 911R2 has a plurality of slits 911s2 formed therein, each extending parallel to the director of the liquid crystal domain B.

[0010] The second pixel electrode portion 911P2 includes a third slit formation region 911R3 corresponding to the liquid crystal domain C and a fourth slit formation region 911R4 corresponding to the liquid crystal domain D. The third slit formation region 911R3 has a plurality of slits 911s3 formed therein and extending parallel to the director of the liquid crystal domain C. The fourth slit formation region 911R4 has a plurality of slits 911s4 formed therein and extending parallel to the director of the liquid crystal domain D.

[0011] By forming the above-described slits 911s1, 911s2, 911s3, and 911s4 in the pixel electrode 911, the width of the dark line that appears in the pixel 900P can be reduced, and the transmittance can be improved.

[0012] The pixel electrode 911 also has a connecting portion 911P3 and a pair of cutout portions 911u provided between the first pixel electrode portion 911P1 and the second pixel electrode portion 911P2. The connecting portion 911P3 is located at the center of the pixel electrode 911 in the width direction (the short side direction of the pixel 900P) and connects the first pixel electrode portion 911P1 and the second pixel electrode portion 911P2. The pair of cutout portions 911u are formed on both sides of the connecting portion 911P3.

[0013] When a voltage is applied to the liquid crystal layer to form four liquid crystal domains A, B, C, and D as shown in FIG. 34, a double dark line appears between liquid crystal domain B and liquid crystal domain C, i.e., between the first pixel electrode portion 911P1 and the second pixel electrode portion 911P2. In the liquid crystal display device of Patent Document 2, a cutout portion 911u is provided between the first pixel electrode portion 911P1 and the second pixel electrode portion 911P2, thereby reducing the area of ​​the double dark line. Furthermore, a disclination (a point of discontinuity in the liquid crystal alignment) of the double dark line appears on the connecting portion 911P3 (i.e., the position where the disclination occurs is fixed), thereby stabilizing the alignment. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] International Publication No. 2006 / 132369 [Patent Document 2] International Publication No. 2020 / 044557 Summary of the Invention [Problem to be solved by the invention]

[0015] However, after detailed investigation, the inventors of the present application found that even when the electrode structure disclosed in Patent Document 2 is adopted, new disclinations may occur above the cutout portion 911u when the pixel size is relatively large and the cutout portion 911u is long. The new disclinations may occur at different positions, causing display defects such as afterimages. While it is possible to shield the cutout portion 911u from light using a black matrix or the like, this would result in a decrease in transmittance.

[0016] The present invention has been made in view of the above-mentioned problems, and its object is to suppress display defects caused by discontinuous points in the liquid crystal alignment in a VA mode liquid crystal display device in which a multi-alignment structure is formed by defining the pretilt direction with an alignment film. [Means for solving the problem]

[0017] The present specification discloses a liquid crystal display device described in the following items.

[0018] [Item 1] a first substrate and a second substrate facing each other; a vertical alignment type liquid crystal layer provided between the first substrate and the second substrate, A liquid crystal display device having a plurality of pixels, the first substrate has pixel electrodes provided in the plurality of pixels, and a first alignment film provided between the pixel electrodes and the liquid crystal layer; the second substrate has a counter electrode facing the pixel electrode and a second alignment film provided between the counter electrode and the liquid crystal layer; each of the plurality of pixels has a first liquid crystal domain, a second liquid crystal domain, a third liquid crystal domain, and a fourth liquid crystal domain, which have mutually different reference alignment directions defined by the first alignment film and the second alignment film; when the longitudinal direction and the lateral direction of each of the plurality of pixels are called a pixel longitudinal direction and a pixel lateral direction, respectively, and the reference alignment directions of the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are called a first direction, a second direction, a third direction, and a fourth direction, respectively, the first direction, the second direction, the third direction, and the fourth direction form an angle with the pixel lateral direction that is approximately equal to an odd multiple of 45°, the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are arranged in this order along the longitudinal direction of the pixel; When an azimuth angle in the pixel short-side direction is 0°, the second direction and the third direction are approximately 135° and 315° directions, respectively, or approximately 45° and 225° directions, respectively; The pixel electrode is a first slit forming region, which is a region corresponding to the first liquid crystal domain and in which a plurality of first slits extending substantially parallel to the first direction are formed; a second slit forming region in which a plurality of second slits extending substantially parallel to the second direction are formed, the second slit forming region being a region corresponding to the second liquid crystal domain; a third slit forming region, which is a region corresponding to the third liquid crystal domain and in which a plurality of third slits extending substantially parallel to the third direction are formed; a fourth slit forming region in which a plurality of fourth slits extending substantially parallel to the fourth direction are formed, the fourth slit forming region being a region corresponding to the fourth liquid crystal domain; a boundary region located between the second slit forming region and the third slit forming region; and The boundary region is n (n is an integer of 3 or more) boundary slits each extending substantially parallel to the pixel short-side direction, the n boundary slits being aligned along the pixel short-side direction; (n-1) first connecting portions, each of which is located between two adjacent boundary slits among the n boundary slits and connects the second slit forming region and the third slit forming region; (n-2) recessed patterns each located between two adjacent first connecting portions among the (n-1) first connecting portions, each including a first recessed portion formed so as to recess from a boundary slit located between the two first connecting portions toward the second slit formation region and a second recessed portion formed so as to recess toward the third slit formation region; A liquid crystal display device comprising:

[0019] [Item 2] Item 2. The liquid crystal display device according to item 1, wherein the distance from each of the (n-2) recessed patterns to each of the two first connecting portions adjacent to that recessed pattern is 10 μm or more and 30 μm or less.

[0020] [Item 3] 3. The liquid crystal display device according to item 1 or 2, wherein the width of each of the (n-1) first connecting portions along the pixel short-side direction is 2.5 μm or more and 3.5 μm or less.

[0021] [Item 4] 4. The liquid crystal display device according to any one of items 1 to 3, wherein the length of each of the first recessed portion and the second recessed portion along the pixel longitudinal direction is 1.5 μm or more.

[0022] [Item 5] 5. The liquid crystal display device according to any one of items 1 to 4, wherein the boundary region is located at both ends of the pixel electrode in the pixel short-side direction and further includes two second connecting portions that connect the second slit formation region and the third slit formation region.

[0023] [Item 6] Item 6. The liquid crystal display device according to item 5, wherein the width of each of the two second connecting portions along the pixel short-side direction is 6.0 μm or more.

[0024] [Item 7] a first substrate and a second substrate facing each other; a vertical alignment type liquid crystal layer provided between the first substrate and the second substrate, A liquid crystal display device having a plurality of pixels, the first substrate has pixel electrodes provided in the plurality of pixels, and a first alignment film provided between the pixel electrodes and the liquid crystal layer; the second substrate has a counter electrode facing the pixel electrode and a second alignment film provided between the counter electrode and the liquid crystal layer; each of the plurality of pixels has a first liquid crystal domain, a second liquid crystal domain, a third liquid crystal domain, and a fourth liquid crystal domain, which have mutually different reference alignment directions defined by the first alignment film and the second alignment film; when the longitudinal direction and the lateral direction of each of the plurality of pixels are called a pixel longitudinal direction and a pixel lateral direction, respectively, and the reference alignment directions of the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are called a first direction, a second direction, a third direction, and a fourth direction, respectively, the first direction, the second direction, the third direction, and the fourth direction form an angle with the pixel lateral direction that is approximately equal to an odd multiple of 45°, the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are arranged in this order along the longitudinal direction of the pixel; When an azimuth angle in the pixel short-side direction is 0°, the second direction and the third direction are approximately 135° and 315° directions, respectively, or approximately 45° and 225° directions, respectively; The pixel electrode is a first slit forming region, which is a region corresponding to the first liquid crystal domain and in which a plurality of first slits extending substantially parallel to the first direction are formed; a second slit forming region in which a plurality of second slits extending substantially parallel to the second direction are formed, the second slit forming region being a region corresponding to the second liquid crystal domain; a third slit forming region, which is a region corresponding to the third liquid crystal domain and in which a plurality of third slits extending substantially parallel to the third direction are formed; a fourth slit forming region in which a plurality of fourth slits extending substantially parallel to the fourth direction are formed, the fourth slit forming region being a region corresponding to the fourth liquid crystal domain; a boundary region located between the second slit forming region and the third slit forming region; and The boundary region is n boundary slits (n is an integer of 3 or more) each extending substantially parallel to the pixel short-side direction, and n boundary slits aligned along the pixel short-side direction; (n-1) first connecting portions, each of which is located between two adjacent boundary slits among the n boundary slits and connects the second slit forming region and the third slit forming region; Including, A liquid crystal display device, wherein, among the n boundary slits, a boundary slit located between two adjacent first connecting portions has a first portion extending approximately parallel to the pixel short side direction, and a second portion extending approximately parallel to the pixel short side direction and whose position in the pixel long side direction is offset from that of the first portion.

[0025] [Item 8] the second direction and the third direction are approximately 45° and 225° directions, respectively; the second portion is adjacent to the first portion in a direction of approximately 0°; 8. The liquid crystal display device according to item 7, wherein the position of the second portion in the pixel longitudinal direction is shifted 90° from the position of the first portion.

[0026] [Item 9] the second direction and the third direction are approximately 135° and 315° directions, respectively; the second portion is adjacent to the first portion in a direction of approximately 0°; 8. The liquid crystal display device according to item 7, wherein the position of the second portion in the pixel longitudinal direction is shifted 270° from the first portion.

[0027] [Item 10] 10. The liquid crystal display device according to any one of items 7 to 9, wherein the length of each of the first portion and the second portion along the pixel short-side direction is 10 μm or more and 30 μm or less.

[0028] [Item 11] 11. The liquid crystal display device according to items 7 to 10, wherein the width of each of the (n-1) first connecting portions along the pixel short-side direction is 2.5 μm or more and 3.5 μm or less.

[0029] [Item 12] Item 12. The liquid crystal display device according to any one of items 7 to 11, wherein the amount of misalignment between the first portion and the second portion in the pixel longitudinal direction is 1.5 μm or more.

[0030] [Item 13] Item 13. The liquid crystal display device according to any one of items 7 to 12, wherein the boundary region is located at both ends of the pixel electrode in the pixel short direction and further includes two second connecting portions that connect the second slit formation region and the third slit formation region.

[0031] [Item 14] Item 14. The liquid crystal display device according to item 13, wherein the width of each of the two second connecting portions along the pixel short-side direction is 6.0 μm or more.

[0032] [Item 15] 15. The liquid crystal display device according to any one of items 1 to 14, wherein each of the first alignment film and the second alignment film is a photo-alignment film.

[0033] [Item 16] 16. The liquid crystal display device according to any one of items 1 to 15, wherein in each of the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain, a pretilt direction defined by the first alignment film and a pretilt direction defined by the second alignment film are approximately antiparallel to each other. [Effects of the Invention]

[0034] According to an embodiment of the present invention, in a VA mode liquid crystal display device in which a multi-domain structure is formed by defining the pretilt direction with an alignment film, display defects caused by discontinuous points in the liquid crystal alignment can be suppressed. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 is a cross-sectional view schematically showing a liquid crystal display device 100 according to an embodiment of the present invention. [Figure 2] 1 is a diagram showing the multi-domain structure of a pixel P in a liquid crystal display device 100. FIG. [Figure 3A] 1 is a diagram for explaining a method for obtaining the multi-domain structure of pixel P, and shows pretilt directions PD1, PD2, PD3, and PD4 defined by a first alignment film 12 of an active matrix substrate 10. FIG. [Figure 3B] 1 is a diagram for explaining a method for obtaining the multi-domain structure of pixel P, and shows pretilt directions PD5, PD6, PD7, and PD8 defined by a second alignment film 22 provided on an opposing substrate 20. FIG. [Figure 3C]This is a diagram for explaining a method for obtaining the alignment division structure of pixel P, and shows the tilt direction (director) when a voltage is applied to the liquid crystal layer 30 after the active matrix substrate 10 and the counter substrate 20 are bonded together. [Figure 4] 1 is a plan view schematically illustrating a liquid crystal display device 100, showing a region corresponding to one pixel P. FIG. [Figure 5] 1 is a plan view schematically showing a pixel electrode 11 of a liquid crystal display device 100. FIG. [Figure 6] 2 is an enlarged plan view showing the vicinity of a boundary region BR of a pixel electrode 11. FIG. [Figure 7A] 1 is a diagram showing the alignment state of liquid crystal molecules 31 in the vicinity of one of two types of discontinuous points of the liquid crystal alignment. [Figure 7B] 10 is a diagram showing the alignment state of liquid crystal molecules 31 in the vicinity of the other of the two types of discontinuous points of the liquid crystal alignment. FIG. [Figure 8A] 10 is a diagram showing the alignment state of liquid crystal molecules 31 in the vicinity of a first connection portion 11c1 in a boundary region BR. FIG. [Figure 8B] 10 is a diagram showing the alignment state of liquid crystal molecules 31 in the vicinity of a recessed pattern 11d in a boundary region BR. FIG. [Figure 9] 10 is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display in the liquid crystal display device 100. FIG. [Figure 10A] 10 is a plan view showing the vicinity of a boundary region BR of a pixel electrode 11A of Comparative Example 1. FIG. [Figure 10B] 10 is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display when a pixel electrode 11A of Comparative Example 1 is used. FIG. [Figure 11A] 10 is a plan view showing the vicinity of the boundary region BR of a pixel electrode 11B of Comparative Example 2. FIG. [Figure 11B] 10 is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display when a pixel electrode 11B of Comparative Example 2 is used. FIG. [Figure 12A]11 is a plan view showing the vicinity of the boundary region BR of a pixel electrode 11C of Comparative Example 3. FIG. [Figure 12B] 10 is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display when a pixel electrode 11C of Comparative Example 3 is used. FIG. [Figure 13A] 13 is a plan view showing the vicinity of the boundary region BR of a pixel electrode 11D of Comparative Example 4. FIG. [Figure 13B] 10 is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display when a pixel electrode 11D of Comparative Example 4 is used. FIG. [Figure 14A] 10 is a plan view showing another example of the structure of the boundary region BR of the pixel electrode 11. FIG. [Figure 14B] 14B is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display when the pixel electrode 11 shown in FIG. 14A is used. FIG. [Figure 15] 2 is an enlarged plan view showing the vicinity of a boundary region BR of a pixel electrode 11. FIG. [Figure 16A] 10 is a plan view showing yet another example of the structure of the boundary region BR of the pixel electrode 11. FIG. [Figure 16B] 16B is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display when the pixel electrode 11 shown in FIG. 16A is used. FIG. [Figure 17] 1 is a plan view schematically illustrating another liquid crystal display device 200 according to an embodiment of the present invention, showing a region corresponding to one pixel P. FIG. [Figure 18] 1 is a plan view schematically showing a pixel electrode 11 of a liquid crystal display device 200. FIG. [Figure 19] 1 is an enlarged plan view showing the vicinity of a boundary region BR of a pixel electrode 11 of a liquid crystal display device 200. FIG. [Figure 20] 10 is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display in the liquid crystal display device 200. FIG. [Figure 21] 1 is a plan view schematically illustrating a liquid crystal display device 300 according to a further embodiment of the present invention, showing a region corresponding to one pixel P. FIG. [Figure 22] FIG. 2 is a plan view schematically showing a pixel electrode 11 of a liquid crystal display device 300. [Figure 23] 1 is an enlarged plan view showing the vicinity of a boundary region BR of a pixel electrode 11 of a liquid crystal display device 300. FIG. [Figure 24] 10 is a diagram showing the alignment state of liquid crystal molecules 31 in the vicinity of a connection portion p3 of the inner boundary slit 11bsi. FIG. [Figure 25] 10 is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display in the liquid crystal display device 300. FIG. [Figure 26A] 11 is a plan view showing the vicinity of the boundary region BR of a pixel electrode 11E of Comparative Example 5. FIG. [Figure 26B] 10 is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display when a pixel electrode 11E of Comparative Example 5 is used. FIG. [Figure 27A] 13 is a plan view showing the vicinity of the boundary region BR of a pixel electrode 11F of Comparative Example 6. FIG. [Figure 27B] 10 is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display when a pixel electrode 11F of Comparative Example 6 is used. FIG. [Figure 28A] 10 is a plan view showing another example of the structure of the boundary region BR in the pixel electrode 11 of the liquid crystal display device 300. FIG. [Figure 28B] 28B is a diagram showing the results of a simulation of the transmittance distribution in pixel P during white display when the pixel electrode 11 shown in FIG. 28A is used. FIG. [Figure 29A] 13 is a plan view showing the vicinity of the boundary region BR of a pixel electrode 11G of Comparative Example 7. FIG. [Figure 29B] 13 is a diagram showing the results of a simulation of the transmittance distribution in a pixel P during white display when a pixel electrode 11G of Comparative Example 7 is used. FIG. [Figure 30] 1 is an enlarged plan view showing the vicinity of a boundary region BR of a pixel electrode 11 of a liquid crystal display device 300. FIG. [Figure 31]10 is a diagram showing another example of the multi-domain structure of the pixel P in the liquid crystal display devices 100, 200, and 300. FIG. [Figure 32] 32 is a plan view showing an example of the structure of a pixel electrode 11 when the multi-domain structure shown in FIG. 31 is adopted. FIG. [Figure 33] 32 is a diagram showing an example of the structure of a boundary region BR of a pixel electrode 11 when the multi-domain structure shown in FIG. 31 is adopted. FIG. [Figure 34] FIG. 10 is a diagram showing a domain arrangement in a pixel 900P disclosed in Patent Document 2. [Figure 35] FIG. 10 is a plan view showing a pixel electrode 911 disclosed in Patent Document 2. DETAILED DESCRIPTION OF THE INVENTION

[0036] [Terminology] First, the main terms used in this specification will be explained.

[0037] In this specification, a "vertically aligned liquid crystal layer" refers to a liquid crystal layer in which liquid crystal molecules are aligned substantially perpendicular (for example, at an angle of approximately 85° or more) to the surface of an alignment film (vertically aligned film). The liquid crystal molecules contained in a vertically aligned liquid crystal layer have negative dielectric anisotropy. A normally black mode display is achieved by combining a vertically aligned liquid crystal layer with a pair of polarizers arranged in a crossed Nicol configuration (i.e., arranged so that their transmission axes are substantially perpendicular to each other) facing each other via the liquid crystal layer.

[0038] In this specification, the term "pixel" refers to the smallest unit that expresses a specific gradation in a display, and in a color display, for example, corresponds to a unit that expresses each of the gradations of R, G, and B. A combination of an R pixel, a G pixel, and a B pixel constitutes one color display pixel. In this specification, the region (pixel region) of a liquid crystal display device that corresponds to a display "pixel" is also called a "pixel."

[0039] The "pretilt direction" is the alignment direction of liquid crystal molecules determined by the alignment film, and refers to the azimuthal direction within the display surface. The angle that the liquid crystal molecules make with the surface of the alignment film is called the "pretilt angle." The alignment treatment of the alignment film (a treatment for imparting the ability to determine a pretilt direction in a predetermined direction to the alignment film) is preferably performed by a photo-alignment treatment, as described below.

[0040] By changing the combination of pretilt directions of a pair of alignment films facing each other through a liquid crystal layer, a four-division structure can be formed. Each pixel (pixel region) divided into four has four liquid crystal domains.

[0041] Each liquid crystal domain is characterized by the tilt direction (sometimes called the "reference alignment direction") of the liquid crystal molecules near the center in the plane and thickness direction of the liquid crystal layer when a voltage is applied to the liquid crystal layer. This tilt direction (reference alignment direction) has a dominant influence on the viewing angle dependence of each domain. The tilt direction is the azimuthal direction indicated by the component of the vector (projected shadow onto the substrate plane) of the tilted liquid crystal molecule pointing from the end closest to the rear substrate to the end farther away (i.e., the end closest to the front substrate) of the tilted liquid crystal molecule (the vector pointing from the tip of a pin to the head, as shown in Figure 3C, described below). The reference for the azimuthal direction is the horizontal direction of the display surface, with counterclockwise rotation being positive (if the display surface is like a clock face, the 3 o'clock direction is the azimuthal angle 0°, and counterclockwise rotation is positive). By setting the tilt directions of the four liquid crystal domains to four directions where the angle between any two directions is approximately equal to an integral multiple of 90° (for example, 10:30, 7:30, 4:30, and 1:30), the viewing angle characteristics are averaged, resulting in a good display. From the viewpoint of uniformity of the viewing angle characteristics, it is preferable that the areas occupied by the four liquid crystal domains within the pixel region are approximately equal to each other.

[0042] The vertical alignment type liquid crystal layer exemplified in the following embodiments contains liquid crystal molecules with negative dielectric anisotropy (nematic liquid crystal material with negative dielectric anisotropy), and the pretilt direction determined by one alignment film and the pretilt direction determined by the other alignment film are approximately antiparallel to each other. Of these two pretilt directions, the tilt direction (reference alignment direction) is determined in the azimuthal direction that approximately coincides with the pretilt direction determined by the alignment film on the rear side, and when a voltage is applied to the liquid crystal layer, the liquid crystal molecules do not adopt a twisted alignment. It is preferable that the pretilt angles determined by each of the pair of alignment films are approximately equal to each other.

[0043] As the alignment treatment for the alignment film, photo-alignment treatment is preferable from the viewpoint of mass productivity. Furthermore, since the photo-alignment treatment can be performed without contact, there is no generation of static electricity due to friction as in the rubbing treatment, and a decrease in yield can be prevented. Furthermore, by using a photo-alignment film containing a photosensitive group, the variation in the pretilt angle can be suppressed.

[0044] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

[0045] [Embodiment 1] A liquid crystal display device 100 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view schematically showing the liquid crystal display device 100.

[0046] As shown in Fig. 1, the liquid crystal display device 100 includes 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 an opposing substrate (second substrate) 20, which face each other, and a vertically aligned liquid crystal layer 30 provided between them. The backlight 102 is disposed on the rear side (the side opposite to the viewer) of the liquid crystal display panel 101. The liquid crystal display device 100 also has a plurality of pixels arranged in a matrix.

[0047] The active matrix substrate 10 has pixel electrodes 11 provided in each of the plurality of 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 facing the liquid crystal layer 30). The pixel electrodes 11 and the first alignment film 12 are provided in this order on the surface of the substrate 10a facing the liquid crystal layer 30. In other words, the pixel electrodes 11 and the first alignment film 12 are supported by the substrate 10a.

[0048] The substrate 10a is transparent and insulating, and is, for example, a glass substrate or a plastic substrate.

[0049] The pixel electrode 11 is made of a transparent conductive material (for example, ITO) and has a plurality of slits 11s.

[0050] Although not shown here, in addition to the pixel electrodes 11 and first alignment film 12 described above, the active matrix substrate 10 also includes thin film transistors (TFTs) electrically connected to the pixel electrodes 11, gate wiring that supplies scanning signals (gate signals) to the TFTs, and source wiring that supplies display signals (source signals) to the TFTs.

[0051] The counter substrate 20 has a counter electrode 21 facing the pixel electrodes 11, and a second alignment film 22 provided between the counter electrode 21 and the liquid crystal layer 30 (i.e., on the outermost surface of the counter substrate 20 facing the liquid crystal layer 30). The counter electrode 21 and the second alignment film 22 are provided in this order on the surface of the substrate 20a facing the liquid crystal layer 30. In other words, the counter electrode 21 and the second alignment film 22 are supported by the substrate 20a.

[0052] The substrate 20a is transparent and insulating, and is, for example, a glass substrate or a plastic substrate.

[0053] The counter electrode 21 is made of a transparent conductive material (e.g., ITO). The counter electrode 21 may be a continuous conductive film formed across the entire display area. In other words, the counter electrode 21 may be a common electrode to which a common potential is applied for all pixels.

[0054] Although not shown here, the counter substrate 20 has a color filter layer and a light-shielding layer (black matrix) in addition to the above-mentioned counter electrode 21 and second photo-alignment film 22. The color filter layer typically includes a red color filter, a green color filter, and a blue color filter.

[0055] The first alignment film 12 and the second alignment film 22 have an alignment regulating force that aligns liquid crystal molecules substantially perpendicular to their surfaces. In this embodiment, the first alignment film 12 and the second alignment film 22 have been subjected to a photo-alignment treatment. That is, each of the first alignment film 12 and the second alignment film 22 is a photo-alignment film.

[0056] The liquid crystal display device 100 further includes a pair of polarizing plates 41 and 42 facing each other across the liquid crystal layer 30. The pair of polarizing plates 41 and 42 are arranged so that their transmission axes are substantially perpendicular to each other (i.e., in a crossed Nicol state).

[0057] Next, the multi-domain structure in each pixel P of the liquid crystal display device 100 will be described with reference to FIG.

[0058] In this embodiment, each pixel P has a substantially rectangular shape with a longitudinal direction D1 and a lateral direction D2. Hereinafter, the longitudinal direction D1 and the lateral direction D2 of the pixel P may be referred to as the "pixel longitudinal direction D1" and the "pixel lateral direction D2," respectively.

[0059] 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 in each pixel P, as shown in Figure 2. The four directors (reference alignment directions) t1, t2, t3, and t4 representing the alignment directions of the liquid crystal molecules contained in the liquid crystal domains A, B, C, and D, respectively, have different orientations. The directors of the liquid crystal domains A, B, C, and D are determined by the first alignment film 12 and the second alignment film 22.

[0060] If the horizontal azimuth angle (3 o'clock direction) on the display surface is 0°, the azimuth of the director t1 in the liquid crystal domain A is approximately 315°, the azimuth of the director t2 in the liquid crystal domain B is approximately 45°, the azimuth of the director t3 in the liquid crystal domain C is approximately 225°, and the azimuth of the director t4 in the liquid crystal domain D is approximately 135°. In other words, the difference between any two of the azimuths of the four directors t1, t2, t3, and t4 in the liquid crystal domains A, B, C, and D is approximately equal to an integer multiple of 90°. In this specification, the approximately 45° direction, the approximately 135° direction, the approximately 225° direction, and the approximately 315° direction mean the "40° to 50° direction," the "130° to 140° direction," the "220° to 230° direction," and the "310° to 320° direction," respectively. The directors t1, t2, t3 and t4 of the liquid crystal domains A, B, C and D form an angle approximately equal to an odd multiple of 45° with respect to the pixel width direction D2.

[0061] In the example shown in FIG. 2, four liquid crystal domains A, B, C, and D are arranged in four rows and one column in a pixel P. More specifically, in a pixel P, the liquid crystal domains A, B, C, and D are arranged in this order from top to bottom (i.e., along the pixel longitudinal direction D1). Hereinafter, the four liquid crystal domains (i.e., the liquid crystal domains A, B, C, and D, respectively) may be referred to as the "first liquid crystal domain," the "second liquid crystal domain," the "third liquid crystal domain," and the "fourth liquid crystal domain" in order from top to bottom. The director orientations of any two adjacent liquid crystal domains among the liquid crystal domains A, B, C, and D differ by approximately 90° or approximately 180°. More specifically, the director orientations of the first liquid crystal domain (liquid crystal domain A) and the second liquid crystal domain (liquid crystal domain B) differ by approximately 90°. In addition, the director orientation differs by approximately 180° between the second liquid crystal domain (liquid crystal domain B) and the third liquid crystal domain (liquid crystal domain C), and the director orientation differs by approximately 90° between the third liquid crystal domain (liquid crystal domain C) and the fourth liquid crystal domain (liquid crystal domain D).

[0062] One of the transmission axes (polarization axes) PA1 and PA2 of the pair of polarizers 41 and 42 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 of the directors t1, t2, t3, and t4 of the liquid crystal domains A, B, C, and D.

[0063] 2 illustrates an example in which the four liquid crystal domains A, B, C, and D occupy the same area within pixel P, but the areas of the four liquid crystal domains A, B, C, and D do not have to be equal. However, from the perspective of uniform viewing angle characteristics, it is preferable that the difference in area among the four liquid crystal domains A, B, C, and D is as small as possible. The example shown in FIG. 2 is an example of a four-division structure that is most preferable (i.e., ideal) in terms of viewing angle characteristics.

[0064] Next, an alignment division method for obtaining the alignment division structure of pixel P will be described with reference to FIGS. 3A, 3B, and 3C. FIG. 3A shows pretilt directions PD1, PD2, PD3, and PD4 defined by a first alignment film 12 provided on an active matrix substrate 10, and FIG. 3B shows pretilt directions PD5, PD6, PD7, and PD8 defined by a second alignment film 22 provided on a counter substrate 20. FIG. 3C shows the tilt directions (directors) when a voltage is applied to a liquid crystal layer 30 after the active matrix substrate 10 and the counter substrate 20 are bonded together. Note that FIGS. 3A, 3B, and 3C are views of the active matrix substrate, the counter substrate, and the liquid crystal layer as viewed from the viewer's side. Therefore, in FIG. 3A, the alignment film is located on the near side of the substrate, while in FIG. 3B, the alignment film is located on the far side of the substrate. The pretilt direction and tilt direction are shown as pins, with the head of the pin (the end with the larger area) representing the end on the front side (viewer side) of the liquid crystal molecule, and the tip of the pin (the end with the smaller area) representing the end on the back side of the liquid crystal molecule.

[0065] 3A, the first alignment film 12 has a first pretilt region 12a, a second pretilt region 12b, a third pretilt region 12c, and a fourth pretilt region 12d that define different first pretilt directions PD1, PD2, PD3, and PD4 in each pixel P. Specifically, the region of the first alignment film 12 corresponding to one pixel P is divided into four regions in the vertical direction, and optical alignment treatment is performed so that the respective regions (first pretilt region, second pretilt region, third pretilt region, and fourth pretilt region) 12a, 12b, 12c, and 12d define different pretilt directions (first pretilt direction, second pretilt direction, third pretilt direction, and fourth pretilt direction) PD1, PD2, PD3, and PD4. Here, the photo-alignment treatment is performed by obliquely irradiating ultraviolet light (for example, linearly polarized ultraviolet light) from the direction indicated by the arrow.

[0066] 3B, the second alignment film 22 has a fifth pretilt region 22a, a sixth pretilt region 22b, a seventh pretilt region 22c, and an eighth pretilt region 22d that define different fifth pretilt directions PD5, PD6, PD7, and PD8 in each pixel P. Specifically, the region of the second alignment film 22 corresponding to one pixel P is divided into four regions in the vertical direction, and optical alignment treatment is performed so that the respective regions (fifth pretilt region, sixth pretilt region, seventh pretilt region, and eighth pretilt region) 22a, 22b, 22c, and 22d define different pretilt directions (fifth pretilt direction, sixth pretilt direction, seventh pretilt direction, and eighth pretilt direction) PD5, PD6, PD7, and PD8. Here, the photo-alignment treatment is performed by obliquely irradiating ultraviolet light (for example, linearly polarized ultraviolet light) from the direction indicated by the arrow.

[0067] 3A and 3B, the active matrix substrate 10 and the counter substrate 20 are bonded together to form pixels P with multiple alignments, as shown in Fig. 3C. In each of the liquid crystal domains A to D, the pretilt direction defined by the first alignment film 12 on the active matrix substrate 10 side and the pretilt direction of the second alignment film 22 on the counter substrate 20 side are approximately antiparallel to each other, and the twist angle of the liquid crystal molecules in each of the liquid crystal domains A to D is substantially 0°.

[0068] Dark lines DL1 to DL7 appear in pixel P having a multi-domain structure. Specifically, dark lines DL1, DL2, and DL3 appear at the boundaries between adjacent liquid crystal domains, and dark lines DL4, DL5, DL6, and DL7 appear near the edges of pixel electrode 11. The reason for the appearance of the dark lines is described in Patent Documents 1 and 2, and therefore will not be described here. However, the domain arrangement shown in FIG. 2 is one of the arrangements that minimizes the total area of ​​the dark lines that appear in pixel P.

[0069] Next, the structure of the liquid crystal display device 100 will be described in more detail with reference to Fig. 4. Fig. 4 is a plan view showing a region corresponding to one pixel P of the liquid crystal display device 100.

[0070] The active matrix substrate 10 of the liquid crystal display device 100 has a TFT 13, a storage capacitor 14, a gate line 15, a source line 16, and a storage capacitor line 17 in addition to the pixel electrodes 11 and the first alignment film 12 described above.

[0071] The gate lines 15 extend in the row direction, the source lines 16 extend in the column direction, and the storage capacitance lines 17 extend in the row direction as a whole.

[0072] The TFT 13 has a gate electrode 13g, a gate insulating layer (not shown), a semiconductor layer (not shown), a source electrode 13s, and a drain electrode 13d. The gate electrode 13g is electrically connected to a gate wiring 15. In the example shown, a part of the gate wiring 15 (a part overlapping with the semiconductor layer) functions as the gate electrode 13g. The source electrode 13s is electrically connected to a source wiring 16. In the example shown, the source electrode 13s extends from the source wiring 16. The drain electrode 13d is electrically connected to the pixel electrode 11.

[0073] The storage capacitor 14 includes a first capacitor electrode 14a electrically connected to the drain electrode 13d of the TFT 13, and a second capacitor electrode 14b overlapping the first capacitor electrode 14a via a gate insulating layer. In the example shown, the first capacitor electrode 14a extends from the drain electrode 13d of the TFT 13. In the example shown, a part of the storage capacitor line 17 (the part overlapping the first capacitor electrode 14a) functions as the second capacitor electrode 14b.

[0074] As already explained, the pixel electrode 11 has a plurality of slits 11s. A more specific configuration of the pixel electrode 11 will be explained with reference to Fig. 5. Fig. 5 is a plan view showing the pixel electrode 11.

[0075] As shown in Figure 5, the pixel electrode 11 has a first slit formation region R1 which is a region corresponding to liquid crystal domain A (first liquid crystal domain), a second slit formation region R2 which is a region corresponding to liquid crystal domain B (second liquid crystal domain), a third slit formation region R3 which is a region corresponding to liquid crystal domain C (third liquid crystal domain), and a fourth slit formation region R4 which is a region corresponding to liquid crystal domain D (fourth liquid crystal domain).

[0076] The first slit formation region R1 is formed with a plurality of first slits 11s1 extending substantially parallel to the tilt direction (director t1) of the liquid crystal domain A, and the second slit formation region R2 is formed with a plurality of second slits 11s2 extending substantially parallel to the tilt direction (director t2) of the liquid crystal domain B. The third slit formation region R3 is formed with a plurality of third slits 11s3 extending substantially parallel to the tilt direction (director t3) of the liquid crystal domain C, and the fourth slit formation region R4 is formed with a plurality of fourth slits 11s4 extending substantially parallel to the tilt direction (director t4) of the liquid crystal domain D.

[0077] As described above, by forming the slits 11s in the pixel electrode 11, which extend approximately parallel to the tilt direction of the corresponding liquid crystal domain, the width of the dark line that occurs in the pixel P can be reduced, and the transmittance can be improved.

[0078] The arrangement and number of the multiple slits 11s are not limited to the examples shown in Figures 4 and 5. Figures 4 and 5 show an example in which the slits 11s are arranged over substantially the entire pixel P (i.e., over substantially the entire pixel electrode 11), but the slits 11s may be arranged in only a part of the pixel P. Furthermore, there are no particular limitations on the width of each slit 11s or the interval between two adjacent slits 11s, but typically the width of the slits 11s is 2 μm or more and 4 μm or less, and the interval between two adjacent slits 11s is 2 μm or more and 4 μm or less.

[0079] The pixel electrode 11 further has a boundary region BR located between the second slit formation region R2 and the third slit formation region R3. The structure of the boundary region BR of the pixel electrode 11 will be described below with further reference to Figure 6. Figure 6 is an enlarged view showing the vicinity of the boundary region BR of the pixel electrode 11.

[0080] 6, the boundary region BR has n (n is an integer equal to or greater than 3) boundary slits 11bs, (n-1) first connecting portions 11c1, two second connecting portions 11c2, and (n-2) recessed patterns 11d. Here, the example shows a case where n is 3. That is, the numbers of boundary slits 11bs, first connecting portions 11c1, and recessed patterns 11d are 3, 2, and 1, respectively.

[0081] The three boundary slits 11bs extend substantially parallel to the pixel width direction D2 and are aligned along the pixel width direction D2.

[0082] Each of the two first connecting portions 11c1 is located between two adjacent boundary slits 11bs among the three boundary slits 11bs. The first connecting portion 11c1 connects the second slit forming region R2 and the third slit forming region R3.

[0083] The two second connecting portions 11c2 are located at both ends in the pixel short-side direction D2 of the pixel electrode 11. Similar to the first connecting portion 11c1, the second connecting portion 11c2 connects the second slit formation region R2 and the third slit formation region R3.

[0084] Here, of the three boundary slits 11bs, a pair of boundary slits 11bso located outermost in the pixel short-side direction D2 will be referred to as “outer boundary slits,” and the other boundary slits 11bsi will be referred to as “inner boundary slits.” The inner boundary slit 11bsi is located between two first connecting portions 11c1.

[0085] The recess pattern 11d includes a first recess 11d1 and a second recess 11d2. The first recess 11d1 is formed so as to recess from the inner boundary slit 11bsi toward the second slit-forming region R2. In contrast, the second recess 11d2 is formed so as to recess from the inner boundary slit 11bsi toward the third slit-forming region R3. As such, the first recess 11d1 and the second recess 11d2 are each cutout portions continuous with the inner boundary slit 11bsi, and these are collectively referred to as the recess pattern 11d.

[0086] In the example shown, the first recessed portion 11d1 is trapezoidal in shape and its width narrows from the inner boundary slit 11bsi side toward the second slit forming region R2 side, and the second recessed portion 11d2 is trapezoidal in shape and its width narrows from the inner boundary slit 11bsi side toward the third slit forming region R3 side.

[0087] In the illustrated example, the positions of the first recessed portion 11d1 and the second recessed portion 11d in the pixel width direction D2 are substantially the same (i.e., substantially aligned). Furthermore, in the illustrated example, the position of the recessed pattern 11d in the pixel width direction D2 is approximately the center of the inner boundary slit 11bsi in the longitudinal direction, and is a position that approximately bisects the inner boundary slit 11bsi.

[0088] Since the recessed pattern 11d includes a first recessed portion 11d1 and a second recessed portion 11d2 that are continuous with the inner boundary slit 11bsi, it is naturally located between two adjacent first connecting portions 11c1. In other words, the first connecting portions 11c1, the recessed pattern 11d, and the first connecting portions 11c1 are aligned along the pixel short-side direction D2.

[0089] The liquid crystal display device 100 of this embodiment can suppress display defects caused by discontinuous points in the liquid crystal alignment because the boundary region BR of the pixel electrode 11 has the above-mentioned structure. The reason for this will be explained below.

[0090] Because the orientation of the liquid crystal molecules within a pixel P is point-symmetric, there is always a point of discontinuity in the orientation (a point where four dark lines converge) approximately in the center of the pixel P. The location of this discontinuity is not fixed and can move depending on the voltage applied to the pixel P and the surrounding pixels P (i.e., the location of the discontinuity varies), which can result in display defects such as afterimages.

[0091] In the electrode structure disclosed in Patent Document 2, as shown in Figure 35, the connecting portion 911P3 provided between the first pixel electrode portion 911P1 and the second pixel electrode portion 911P2 can be a structure that fixes the discontinuous point (hereinafter referred to as an "orientation fixing pattern"). However, if the pixel size increases and the cutout portion 911u becomes longer, a new discontinuous point may occur on the cutout portion 911u.

[0092] As already explained, the orientation of the director t2 in the liquid crystal domain B is approximately 45°, and the orientation of the director t3 in the liquid crystal domain C is approximately 225°. Therefore, the orientations of the directors in the liquid crystal domains B and C differ by approximately 180°. Therefore, in order for the liquid crystal molecules to be continuously aligned, a discontinuous point where four dark lines (Schlieren patterns) converge exists in the boundary region BR. Furthermore, as already explained, the boundary region BR has a boundary slit 11bs. Therefore, the liquid crystal molecules on the boundary slit 11bs tilt in one of two directions approximately parallel to the direction in which the boundary slit 11bs extends. Therefore, there are two types of discontinuous points that can exist in the boundary region BR: the type shown in FIG. 7A and the type shown in FIG. 7B. In each of FIGS. 7A and 7B, the discontinuous points are located approximately at the center of the figure.

[0093] In the type shown in Fig. 7A, the liquid crystal molecules 31 tilt inward (toward the discontinuity) on the left and right of the discontinuity and tilt outward in other locations. In contrast, in the type shown in Fig. 7B, the liquid crystal molecules 31 tilt radially outward from the discontinuity (i.e., the liquid crystal molecules tilt outward both on the left and right of the discontinuity).

[0094] The first connecting portion 11c1 and the recessed pattern 11d in the boundary region BR of the pixel electrode 11 can function as an alignment fixing pattern that fixes discontinuous points in the liquid crystal alignment. Figures 8A and 8B show the alignment state of liquid crystal molecules 31 near the first connecting portion 11c1 and the recessed pattern 11d.

[0095] As can be seen from Fig. 8A, first connecting portion 11c1 functions as an orientation fixing pattern for fixing discontinuous points of the type shown in Fig. 7A. Also, as can be seen from Fig. 8B, recessed pattern 11d functions as an orientation fixing pattern for fixing discontinuous points of the type shown in Fig. 7B. In addition to first connecting portion 11c1 and recessed pattern 11d, second connecting portion 11c2 also exists in boundary region BR, but second connecting portion 11c2 does not function as an orientation fixing pattern.

[0096] In the liquid crystal display device 100 of this embodiment, three alignment fixing patterns (two first connecting portions 11c1 and one recess pattern 11d) are provided in the boundary region BR of the pixel electrode 11, so that even if the pixel size becomes relatively large, it is possible to preferably fix discontinuous points (suppress the occurrence of unfixed discontinuous points).

[0097] 9 shows the results of a simulation of the transmittance distribution in pixel P during white display in the liquid crystal display device 100 of this embodiment. From Fig. 9, it can be seen that in the boundary region BR, discontinuous points are fixed at positions corresponding to each alignment fixing pattern, and no discontinuous points exist in locations other than the alignment fixing patterns.

[0098] 10A is a diagram showing the vicinity of the boundary region BR of the pixel electrode 11A of Comparative Example 1. In the pixel electrode 11A of Comparative Example 1, the boundary region BR has two boundary slits 11bs, one first connecting portion 11c1, and two second connecting portions 11c2. In other words, only one alignment fixing pattern is provided in the boundary region BR.

[0099] Fig. 10B shows the transmittance distribution in pixel P when pixel electrode 11A of Comparative Example 1 is used. Fig. 10B shows that in the boundary region BR, in addition to one discontinuous point fixed at a position corresponding to the alignment fixing pattern, there are two discontinuous points on the right-side boundary slit 11bs.

[0100] 11A is a diagram showing the vicinity of the boundary region BR of the pixel electrode 11B of Comparative Example 2. In the pixel electrode 11B of Comparative Example 2, the boundary region BR has one boundary slit 11bs, one recess pattern 11d, and two second connecting portions 11c2. In other words, only one alignment fixing pattern is provided in the boundary region BR.

[0101] Fig. 11B shows the transmittance distribution in pixel P when pixel electrode 11B of Comparative Example 2 is used. Fig. 11B shows that in the boundary region BR, in addition to one discontinuous point fixed at a position corresponding to the alignment fixing pattern, there are two discontinuous points on the boundary slit 11bs.

[0102] In this way, when only one alignment fixing pattern is provided in the boundary region BR, unlike the liquid crystal display device 100 of this embodiment, new discontinuous points that are not fixed by the alignment fixing pattern may occur on the boundary slit 11bs.

[0103] Furthermore, in the liquid crystal display device 100 of this embodiment, two types of alignment fixing patterns are alternately arranged in the boundary region BR, and the first connecting portions 11c1, not the recessed patterns 11d, are arranged on the outermost sides in the pixel short-side direction D2. This configuration also contributes to suitable fixing of discontinuous points.

[0104] 12A is a diagram showing the vicinity of the boundary region BR of the pixel electrode 11C of Comparative Example 3. In the pixel electrode 11C of Comparative Example 3, the boundary region BR has four boundary slits 11bs, three first connecting portions 11c1, and two second connecting portions 11c2. That is, three alignment fixing patterns are provided in the boundary region BR. However, all three alignment fixing patterns are first connecting portions 11c1 (that is, one type of alignment fixing pattern), and two types of alignment fixing patterns are not provided alternately.

[0105] Fig. 12B shows the transmittance distribution in pixel P when pixel electrode 11C of Comparative Example 3 is used. Fig. 12B shows that in the boundary region BR, in addition to the three discontinuous points fixed at positions corresponding to the three alignment fixing patterns, one discontinuous point is present on each of the second and third boundary slits 11bs from the left.

[0106] In this way, when a plurality of alignment fixing patterns of only one type are arranged in the boundary region BR, new discontinuous points may occur between adjacent alignment fixing patterns. In contrast, in the liquid crystal display device 100 of this embodiment, two types of alignment fixing patterns are arranged alternately, thereby suppressing the occurrence of discontinuous points between adjacent alignment fixing patterns.

[0107] 13A is a diagram showing the vicinity of the boundary region BR of a pixel electrode 11D of Comparative Example 4. In the pixel electrode 11D of Comparative Example 4, the boundary region BR has three boundary slits 11bs, two first connecting portions 11c1, three recessed patterns 11d, and two second connecting portions 11c2. In other words, five alignment fixing patterns are provided in the boundary region BR. However, recessed patterns 11d, rather than first connecting portions 11c1, are arranged at the outermost sides in the pixel short-side direction D2.

[0108] Fig. 13B shows the transmittance distribution in pixel P when pixel electrode 11D of Comparative Example 4 is used. Fig. 13B shows that in the boundary region BR, in addition to the five discontinuous points fixed at positions corresponding to the five alignment fixing patterns, one discontinuous point is present on each of the leftmost and rightmost boundary slits 11bs.

[0109] In this way, when the recessed pattern 11d is arranged on the outermost side in the pixel width direction D2, a new discontinuous point may occur on the outermost boundary slit 11bs. In contrast, in the liquid crystal display device 100 of this embodiment, the first connecting portion 11c1 is arranged on the outermost side in the pixel width direction D2, so that the alignment restriction force at the end of the pixel electrode 11 (which acts to tilt the liquid crystal molecules 31 toward the inside of the pixel P) matches the alignment restriction force of the outermost alignment fixing pattern in the pixel width direction D2, and the occurrence of a discontinuous point on the outermost boundary slit 11bs is suppressed.

[0110] As described above, the liquid crystal display device 100 of this embodiment can effectively suppress display defects caused by discontinuous points in the liquid crystal alignment.

[0111] 5 and other figures show an example in which the boundary region BR of the pixel electrode 11 has three boundary slits 11bs, two first connecting portions 11c1, and one recessed pattern 11d. However, the boundary region BR may have n (n is an integer greater than or equal to 3) boundary slits 11bs, (n-1) first connecting portions 11c1, and (n-2) recessed patterns 11d, and the embodiment of the present invention is not limited to the case where n is 3. The boundary region BR may have a structure shown in FIG. 14A, for example. In the example shown in FIG. 14A, the boundary region BR has four boundary slits 11bs, three first connecting portions 11c1, two second connecting portions 11c2, and two recessed patterns 11d (i.e., n is 4).

[0112] Fig. 14B shows the transmittance distribution in pixel P when the pixel electrode 11 shown in Fig. 14A is used. Fig. 14B shows that in the boundary region BR, discontinuous points are fixed at positions corresponding to each alignment fixing pattern (each of the three first connecting portions 11c1 and each of the two recess patterns 11d), and no discontinuous points exist in locations other than the alignment fixing patterns.

[0113] Here, a preferred structure of the boundary region BR of the pixel electrode 11 will be described with reference to FIG.

[0114] Distances d1 and d2 from recess pattern 11d to each of the two first connecting portions 11c1 adjacent to recess pattern 11d are preferably 10 μm or more and 30 μm or less. From the perspective of reducing the total area of ​​dark lines and achieving high transmittance, it is preferable that distances d1 and d2 be large. However, if distances d1 and d2 exceed 30 μm, discontinuities may occur between recess pattern 11d and the adjacent first connecting portion 11c1. Furthermore, if distances d1 and d2 are less than 10 μm, the effect of inner boundary slit 11bsi may not be fully achieved, resulting in a loss of transmittance.

[0115] The smaller the width w1 of the first connecting portion 11c1 along the pixel short-side direction D2, the less alignment disturbance there will be, but if it is too small, it may be difficult to manufacture. Specifically, the width w1 of the first connecting portion 11c1 is preferably 2.5 μm or more and 3.5 μm or less, for example, approximately 3 μm.

[0116] The lengths L1 and L2 of the first recess 11d1 and the second recess 11d2 along the pixel longitudinal direction D1 are preferably 1.5 μm or more, and more preferably 2 μm or more, from the viewpoint of enabling the recess pattern 11d to function sufficiently as an orientation fixing pattern.

[0117] As described above, although the second connection portion 11c2 does not function as an alignment fixing pattern, the provision of the second connection portion 11c2 enables more reliable electrical connection between the second slit formation region R2 and the third slit formation region R3. That is, the second connection portion 11c2 can function as a redundant structure for electrical connection. From the viewpoint of ensuring electrical connection, the width w2 of the second connection portion 11c2 along the short pixel direction D2 is preferably 6.0 μm or more.

[0118] For the same reasons as described for the distances d1 and d2, the lengths L3 and L4 of the two outer boundary slits 11bso along the short pixel direction D2 are preferably 10 μm or more and 30 μm or less, respectively.

[0119] From the viewpoint of alignment stability, it is preferable that the above-described distances d1, d2, lengths L3, and L4 are substantially the same (that is, substantially d = d2 = L = L4). That is, when the plurality of boundary slits 11bs existing in the boundary region BR are regarded as one continuous slit, it is preferably substantially equally divided by the alignment fixing pattern.

[0120] However, as shown in FIG. 16A, the division by the alignment fixing pattern does not have to be equal division. In the example shown in FIG. 16A, the lengths L3 and L4 are larger than the distances d1 and d2 (that is, d1, d2 < L3, L4). FIG. 16B shows the transmittance distribution in the pixel P when the pixel electrode 11 shown in FIG. 16A is used. It can be seen from FIG. 16B that in the boundary region BR, discontinuity points are fixed at positions corresponding to each alignment fixing pattern, and there are no discontinuity points at locations other than the alignment fixing patterns. Note that, contrary to the example shown in FIG. 16A, the lengths L3 and L4 may be smaller than the distances d1 and d2 (that is, d1, d2 > L3, L4).

[0121] [Embodiment 2] A liquid crystal display device 200 according to this embodiment will be described with reference to Figures 17, 18, and 19. Figure 17 is a plan view showing a region corresponding to one pixel P of the liquid crystal display device 200. Figure 18 is a plan view showing a pixel electrode 11 of the liquid crystal display device 200, and Figure 19 is an enlarged view showing the vicinity of the boundary region BR of the pixel electrode 11. The following explanation will focus on the differences between the liquid crystal display device 200 and the liquid crystal display device 100 according to embodiment 1.

[0122] 17, 18, and 19, the liquid crystal display device 200 differs from the liquid crystal display device 100 of Embodiment 1 in that the boundary region BR of the pixel electrode 11 does not include the second connecting portion 11c2. Even if the second connecting portion 11c2 is omitted, display defects caused by discontinuous points in the liquid crystal alignment can be suppressed, as with the liquid crystal display device 100 of Embodiment 1.

[0123] Fig. 20 shows the transmittance distribution in a pixel P of the liquid crystal display device 200 of this embodiment. From Fig. 20, it can be seen that in the boundary region BR, discontinuous points are fixed at positions corresponding to each alignment fixing pattern, and no discontinuous points exist in any location other than the alignment fixing patterns.

[0124] The second connecting portion 11c2 is omitted in the liquid crystal display device 200 of this embodiment. Therefore, from the viewpoint of more reliably ensuring electrical connection between the second slit formation region R2 and the third slit formation region R3, the width w1 of the first connecting portion 11c1 along the pixel short-side direction D2 is preferably 6.0 μm or more.

[0125] [Embodiment 3] A liquid crystal display device 300 according to this embodiment will be described with reference to Figures 21, 22, and 23. Figure 21 is a plan view showing a region corresponding to one pixel P of the liquid crystal display device 300. Figure 22 is a plan view showing a pixel electrode 11 of the liquid crystal display device 300, and Figure 23 is an enlarged view showing the vicinity of the boundary region BR of the pixel electrode 11. The following explanation will focus on the differences between the liquid crystal display device 300 and the liquid crystal display device 100 according to embodiment 1.

[0126] The pixel electrode 11 of the liquid crystal display device 300 in this embodiment has a first slit forming region R1, a second slit forming region R2, a third slit forming region R3, a fourth slit forming region R4, and a boundary region BR, similar to the pixel electrode 11 of the liquid crystal display device 100 in embodiment 1.

[0127] The boundary region BR of the pixel electrode 11 of the liquid crystal display device 300 has n (n is an integer greater than or equal to 3) boundary slits 11bs, (n-1) first connecting portions 11c1, and two second connecting portions 11c2. Figure 21 and other figures illustrate a case where n is 3. That is, the numbers of boundary slits 11bs and first connecting portions 11c1 are 3 and 2, respectively.

[0128] The three boundary slits 11bs extend substantially parallel to the pixel width direction D2 and are aligned along the pixel width direction D2.

[0129] Each of the two first connecting portions 11c1 is located between two adjacent boundary slits 11bs among the three boundary slits 11bs. The first connecting portion 11c1 connects the second slit forming region R2 and the third slit forming region R3.

[0130] The two second connecting portions 11c2 are located at both ends in the pixel short-side direction D2 of the pixel electrode 11. Similar to the first connecting portion 11c1, the second connecting portion 11c2 connects the second slit formation region R2 and the third slit formation region R3.

[0131] Of the three boundary slits 11bs, the pair of boundary slits 11bso located outermost in the pixel short-side direction D2 will be referred to as the “outer boundary slits,” and the other boundary slits 11bsi will be referred to as the “inner boundary slits.” The inner boundary slit 11bsi is located between two first connecting portions 11b1.

[0132] The inner boundary slit 11bsi has a first portion p1 and a second portion p2, each extending in the pixel short-side direction D2. The second portion p2 is adjacent to the first portion p1 in the direction of approximately 0° (to the right in the figure). That is, the first portion p1 is located relatively to the left, and the second portion p2 is located relatively to the right. The second portion p2 is shifted from the first portion p1 in the pixel long-side direction D1. More specifically, the position of the second portion p2 in the pixel long-side direction D1 is shifted from the first portion p1 in the direction of 90° (toward the upper side in the figure). The first portion p1 and the second portion p2 are connected by a connection portion p3 extending in a direction intersecting the pixel short-side direction D2. In the example shown in the figure, the connection portion p3 is located approximately in the center of the inner boundary slit 11bsi in the longitudinal direction, at a position that approximately bisects the inner boundary slit 11bsi.

[0133] The structure in which the first portion p1 and the second portion p2 are misaligned can function as an alignment fixing pattern that fixes discontinuous points of the liquid crystal alignment, similar to the recess pattern 11d. Figure 24 shows the alignment state of the liquid crystal molecules 31 in the vicinity of the connection part p3.

[0134] As can be seen from Figure 24, the structure in which the first portion p1 and the second portion p2 are misaligned (the region near the connection portion p3) functions as an orientation fixing pattern for fixing the discontinuous point of the type shown in Figure 7B. Hereinafter, the connection portion p3 located at the center of the orientation fixing pattern will also be referred to as the "misalignment portion." It can also be said that the misalignment portion p3 functions as an orientation fixing pattern.

[0135] In the liquid crystal display device 300 of this embodiment, three alignment fixing patterns (two first connecting portions 11c1 and one offset portion p3) are provided in the boundary region BR of the pixel electrode 11, so that even if the pixel size becomes relatively large, it is possible to preferably fix the discontinuous points (suppress the occurrence of non-fixed discontinuous points). Fig. 25 shows the transmittance distribution in a pixel P of the liquid crystal display device 300 of this embodiment. From Fig. 25, it can be seen that in the boundary region BR, discontinuous points are fixed at positions corresponding to each alignment fixing pattern, and no discontinuous points exist in any location other than the alignment fixing patterns.

[0136] 26A is a diagram showing the vicinity of the boundary region BR of the pixel electrode 11E of Comparative Example 5. In the pixel electrode 11E of Comparative Example 5, the boundary region BR has one boundary slit 11bs and two second connecting portions 11c2, and a misalignment portion p3 is provided in the boundary slit 11bs. In other words, only one alignment fixing pattern is provided in the boundary region BR.

[0137] 26B shows the transmittance distribution in pixel P when pixel electrode 11E of Comparative Example 5 is used. From Fig. 26B, it can be seen that in the boundary region BR, in addition to one discontinuous point fixed at a position corresponding to the alignment fixing pattern, there are two discontinuous points on the boundary slit 11bs.

[0138] In this way, when only one orientation fixing pattern is provided in the boundary region BR, unlike the liquid crystal display device 300 of this embodiment, new discontinuous points that are not fixed by the orientation fixing pattern may occur on the boundary slit 11bs.

[0139] Furthermore, in the liquid crystal display device 300 of this embodiment, two types of alignment fixing patterns are alternately arranged in the boundary region BR, and the first connecting portions 11c1, not the offset portions p3, are arranged at the outermost sides in the pixel short-side direction D2. This configuration also contributes to suitable fixing of discontinuous points.

[0140] 27A is a diagram showing the vicinity of the boundary region BR of the pixel electrode 11F of Comparative Example 6. In the pixel electrode 11F of Comparative Example 6, the boundary region BR has three boundary slits 11bs, two first connecting portions 11c1, and two second connecting portions 11c2, and each boundary slit 11bs is provided with a misalignment portion p3. In other words, five alignment fixing patterns are provided in the boundary region BR. However, the misalignment portion p3, not the first connecting portion 11c1, is arranged at the outermost side in the pixel short-side direction D2.

[0141] Fig. 27B shows the transmittance distribution in pixel P when pixel electrode 11F of Comparative Example 6 is used. Fig. 27B shows that in the boundary region BR, in addition to the five discontinuous points fixed at positions corresponding to the five alignment fixing patterns, there is one discontinuous point on the right boundary slit 11bs.

[0142] In this way, when the misalignment portion p3 is arranged on the outermost side in the pixel width direction D2, a new discontinuous point may occur on the outermost boundary slit 11bs. In contrast, in the liquid crystal display device 300 of this embodiment, the first connecting portion 11c1 is arranged on the outermost side in the pixel width direction D2, so that the alignment restriction force at the end of the pixel electrode 11 (which acts to tilt the liquid crystal molecules 31 toward the inside of the pixel P) matches the alignment restriction force of the outermost alignment fixing pattern in the pixel width direction D2, and the occurrence of a discontinuous point on the outermost boundary slit 11bs is suppressed.

[0143] As described above, the liquid crystal display device 300 of this embodiment can effectively suppress display defects caused by discontinuous points in the liquid crystal alignment. Furthermore, as can be seen from a comparison between Fig. 9 and Fig. 25, the liquid crystal display device 300 of this embodiment has a smaller width of the double dark line that appears in the boundary region BR than the liquid crystal display device 100 of Embodiment 1, thereby enabling a further improvement in transmittance. Therefore, even when wiring made of a metal material is disposed in the boundary region BR, the double dark line is sufficiently contained within the width of the wiring, thereby minimizing loss in transmittance.

[0144] 22 and other figures show an example in which the boundary region BR of the pixel electrode 11 has three boundary slits 11bs, two first connecting portions 11c1, and one offset portion p3. However, the boundary region BR may have n (n is an integer greater than or equal to 3) boundary slits 11bs, (n-1) first connecting portions 11c1, and (n-2) offset portions p3, and the embodiment of the present invention is not limited to the case where n is 3. The boundary region BR may have a structure shown in FIG. 28A, for example. In the example shown in FIG. 28A, the boundary region BR has four boundary slits 11bs, three first connecting portions 11c1, two second connecting portions 11c2, and two offset portions p3 (i.e., n is 4).

[0145] Fig. 28B shows the transmittance distribution in pixel P when the pixel electrode 11 shown in Fig. 28A is used. Fig. 28B shows that in the boundary region BR, discontinuous points are fixed at positions corresponding to each alignment fixing pattern (each of the three first connecting portions 11c1 and each of the two offset portions P3), and no discontinuous points exist in locations other than the alignment fixing patterns.

[0146] As illustrated here, when the orientation of the director t2 of the second liquid crystal domain (liquid crystal domain B) is approximately 45° and the orientation of the director t3 of the third liquid crystal domain (liquid crystal domain C) is approximately 225°, in order for the offset portion P3 of the inner boundary slit 11bsi to function properly as an orientation fixing pattern, it is preferable that the position of the second portion p2 in the pixel longitudinal direction D1 is offset 90° from the first portion p1.

[0147] 29A is a diagram showing the vicinity of the boundary region BR of the pixel electrode 11G of Comparative Example 7. In the pixel electrode 11G of Comparative Example 7, the position of the second portion p2 of the inner boundary slit 11bsi in the pixel longitudinal direction D1 is shifted in the 270° direction (downward in the figure) from the first portion p1.

[0148] 29B shows the transmittance distribution in pixel P when pixel electrode 11G of Comparative Example 7 is used. From FIG. 29B, it can be seen that in the inner boundary slit 11bsi, no discontinuous point is fixed at the position corresponding to deviation portion P3.

[0149] Here, a preferred structure of the boundary region BR of the pixel electrode 11 will be described with reference to FIG.

[0150] The lengths L5 and L6 of the first portion p1 and the second portion p2 of the inner boundary slit 11bsi along the pixel width direction D2 are preferably 10 μm or more and 30 μm or less. From the perspective of reducing the total area of ​​dark lines and achieving high transmittance, it is preferable that the lengths L5 and L6 be large. However, if the lengths L5 and L6 exceed 30 μm, a discontinuity may occur between the offset portion P3 and the adjacent first connecting portion 11c1. Furthermore, if the lengths L5 and L6 are less than 10 μm, the effect of the inner boundary slit 11bsi may not be fully achieved, resulting in a loss of transmittance.

[0151] The smaller the width w1 of the first connecting portion 11c1 along the pixel short-side direction D2, the less alignment disturbance there will be, but if it is too small, it may be difficult to manufacture. Specifically, the width w1 of the first connecting portion 11c1 is preferably 2.5 μm or more and 3.5 μm or less, for example, approximately 3 μm.

[0152] From the viewpoint of enabling the misalignment portion p3 of the inner boundary slit 11bsi to function sufficiently as an orientation fixing pattern, the positional misalignment amount d3 between the first portion p1 and the second portion p2 in the pixel longitudinal direction D1 is preferably 1.5 μm or more, and more preferably 2 μm or more.

[0153] As described above, although the second connection portion 11c2 does not function as an orientation fixing pattern, the provision of the second connection portion 11c2 enables more reliable electrical connection between the second slit formation region R2 and the third slit formation region R3. That is, the second connection portion 11c2 can function as a redundant structure for electrical connection. From the viewpoint of ensuring electrical connection, the width w2 of the second connection portion 11c2 along the short pixel direction D2 is preferably 6.0 μm or more.

[0154] For the same reasons as described for the lengths L5 and L6, the lengths L3 and L4 of the two outer boundary slits 11bso along the short pixel direction D2 are preferably 10 μm or more and 30 μm or less, respectively.

[0155] From the viewpoint of orientation stability, it is preferable that the lengths L3, L4, L5, and L6 described above are substantially the same (that is, substantially L3 = L4 = L5 = L6). That is, when the plurality of boundary slits 11bs existing in the boundary region BR are regarded as a single continuous slit, it is preferable that it is substantially equally divided by the orientation fixing pattern.

[0156] However, the division by the orientation fixing pattern does not have to be an equal division. For example, the lengths L3 and L4 may be larger than the lengths L5 and L6 (that is, L5, L6 < L3, L4), or the lengths L3 and L4 may be smaller than the lengths L5 and L6 (that is, L5, L6 > L3, L4).

[0157] Also, the second connection portion 11c2 may be omitted. Even if the second connection portion 11c2 is omitted, display defects caused by non - continuous points of liquid crystal alignment can be suppressed.

[0158] When the second connection portion 11c2 is omitted, from the viewpoint of more reliably ensuring electrical connection between the second slit formation region R2 and the third slit formation region R3, the width w1 of the first connection portion 11c1 along the short pixel direction D2 is preferably 6.0 μm or more.

[0159] [Other domain placements] The arrangement of the liquid crystal domains in the pixel P is not limited to the example shown in Fig. 2. In the example shown in Fig. 2, liquid crystal domains A (reference alignment direction is approximately 315°), B (reference alignment direction is approximately 45°), C (reference alignment direction is approximately 225°), and D (reference alignment direction is approximately 135°) are arranged in this order along the longitudinal direction D1 of the pixel.

[0160] Alternatively, an arrangement such as that shown in Fig. 31 may be adopted. In the example shown in Fig. 31, in a pixel P, liquid crystal domains C, D, A, and B are arranged in this order from top to bottom (i.e., along the longitudinal direction D1 of the pixel). If the four liquid crystal domains (i.e., liquid crystal domains C, D, A, and B) are referred to as the "first liquid crystal domain," the "second liquid crystal domain," the "third liquid crystal domain," and the "fourth liquid crystal domain" in order from top to bottom (i.e., liquid crystal domains C, D, A, and B, respectively), the director orientations differ by approximately 90° between the first liquid crystal domain (liquid crystal domain C) and the second liquid crystal domain (liquid crystal domain D). Furthermore, the director orientations differ by approximately 180° between the second liquid crystal domain (liquid crystal domain D) and the third liquid crystal domain (liquid crystal domain A), and the director orientations differ by approximately 90° between the third liquid crystal domain (liquid crystal domain A) and the fourth liquid crystal domain (liquid crystal domain B).

[0161] When an arrangement such as the example shown in Fig. 31 is adopted, the structure of the pixel electrode 11 may be, for example, the structure shown in Fig. 32. The pixel electrode 11 shown in Fig. 32 has a first slit-forming region R1 which is a region corresponding to the liquid crystal domain C (first liquid crystal domain), a second slit-forming region R2 which is a region corresponding to the liquid crystal domain D (second liquid crystal domain), a third slit-forming region R3 which is a region corresponding to the liquid crystal domain A (third liquid crystal domain), and a fourth slit-forming region R4 which is a region corresponding to the liquid crystal domain B (fourth liquid crystal domain).

[0162] The first slit formation region R1 is formed with a plurality of first slits 11s1 extending substantially parallel to the tilt direction (director t3) of the liquid crystal domain C, and the second slit formation region R2 is formed with a plurality of second slits 11s2 extending substantially parallel to the tilt direction (director t4) of the liquid crystal domain D. The third slit formation region R3 is formed with a plurality of third slits 11s3 extending substantially parallel to the tilt direction (director t1) of the liquid crystal domain A, and the fourth slit formation region R4 is formed with a plurality of fourth slits 11s4 extending substantially parallel to the tilt direction (director t2) of the liquid crystal domain B.

[0163] The boundary region BR of the pixel electrode 11 shown in FIG. 32 has the same structure as the boundary region BR of the pixel electrode 11 shown in FIG. 5. Even when the domain arrangement shown in FIG. 31 is adopted, the boundary region BR of the pixel electrode 11 has the above-mentioned structure, so that the same effect as when the domain arrangement shown in FIG. 2 is adopted can be obtained. Of course, the boundary region BR of the pixel electrode 11 shown in FIG. 32 may have the same structure as the boundary region BR shown in FIGS. 14A, 16A, 19, 23, and 28A. When the same structure as the boundary region BR shown in FIG. 23 is adopted, it is preferable that the position of the second portion p2 of the inner boundary slit 11bsi in the pixel longitudinal direction D1 is shifted 270° in the direction (downward in the figure) from the first portion p1, as shown in FIG. 33. When the orientation of the director t4 of the second liquid crystal domain (liquid crystal domain D) is approximately 135° and the orientation of the director t1 of the third liquid crystal domain (liquid crystal domain A) is approximately 315°, the position of the second portion p2 in the pixel longitudinal direction D1 is shifted by 270° from the first portion p1, so that the shifted portion P3 functions favorably as an alignment fixing pattern. The same applies when the same structure as the boundary region BR shown in FIG. 28A is adopted. [Industrial Applicability]

[0164] The liquid crystal display device according to the embodiment of the present invention is suitable for use in applications requiring high-quality displays, such as television receivers, etc. The embodiment of the present invention is particularly suitable for use in liquid crystal display devices with relatively large pixel sizes. [Explanation of symbols]

[0165] 10 Active matrix substrate (first substrate) 10a substrate 11 Pixel electrode 11s slit 11s1 First slit 11s2 Second slit 11s3 Third slit 11s4 4th slit 11bs Boundary slit 11bsi Inner boundary slit 11bso outer boundary slit 11c1 1st connection part 11c2 2nd connection part 11d recess pattern 11d1 First recess 11d2 Second recess 12 First alignment film 12a First pretilt region 12b Second pretilt region 12c Third pretilt region 12d Fourth pretilt region 13 TFT 13g Gate electrode 13s Source Electrode 13d Drain electrode 14 Auxiliary capacity 14a 1st capacitor electrode 14b 2nd capacitor electrode 15 Gate wiring 16 Source wiring 17 Auxiliary capacitor wiring 20 opposing substrate (second substrate) 20a board 21 Counter electrode 22 Second alignment film 22a Fifth pretilt region 22b 6th pretilt region 22c 7th pretilt region 22d 8th pretilt region 30 Liquid crystal layer 31 Liquid crystal molecules 41, 42 Polarizing plate 100, 200, 300 LCD display 101 LCD display panel 102 Backlight (lighting device) P pixel D1 Pixel longitudinal direction D2 Pixel width direction A, B, C, D liquid crystal domains t1, t2, t3, t4 director (reference orientation direction) PA1, PA2 Polarizer Transmission Axis (Polarization Axis) PD1, PD2, PD3, PD4 Pretilt directions defined by the first alignment film PD5, PD6, PD7, PD8 Pretilt direction determined by the second alignment film DL1, DL2, DL3, DL4, DL5, DL6, DL7 Dark line R1 First slit forming area R2 Second slit forming area R3 Third slit forming area R4 Fourth slit forming area BR boundary area p1 First part of the inner boundary slit p2 First part of the inner boundary slit p3 First part of the inner boundary slit

Claims

1. a first substrate and a second substrate facing each other; a vertical alignment type liquid crystal layer provided between the first substrate and the second substrate, A liquid crystal display device having a plurality of pixels, the first substrate has pixel electrodes provided in the plurality of pixels, and a first alignment film provided between the pixel electrodes and the liquid crystal layer; the second substrate has a counter electrode facing the pixel electrode and a second alignment film provided between the counter electrode and the liquid crystal layer; each of the plurality of pixels has a first liquid crystal domain, a second liquid crystal domain, a third liquid crystal domain, and a fourth liquid crystal domain, which have mutually different reference alignment directions defined by the first alignment film and the second alignment film; when the longitudinal direction and the lateral direction of each of the plurality of pixels are referred to as a pixel longitudinal direction and a pixel lateral direction, respectively, and the reference alignment directions of the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are referred to as a first direction, a second direction, a third direction, and a fourth direction, respectively, the first direction, the second direction, the third direction, and the fourth direction form an angle with the pixel lateral direction that is approximately equal to an odd multiple of 45°, the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are arranged in this order along the pixel longitudinal direction, When an azimuth angle in the pixel short-side direction is 0°, the second direction and the third direction are approximately 135° and 315° directions, respectively, or approximately 45° and 225° directions, respectively; The pixel electrode is a first slit forming region, which is a region corresponding to the first liquid crystal domain and in which a plurality of first slits extending substantially parallel to the first direction are formed; a second slit forming region, which is a region corresponding to the second liquid crystal domain and in which a plurality of second slits extending substantially parallel to the second direction are formed; a third slit forming region, which is a region corresponding to the third liquid crystal domain and in which a plurality of third slits extending substantially parallel to the third direction are formed; a fourth slit forming region, which is a region corresponding to the fourth liquid crystal domain and in which a plurality of fourth slits extending substantially parallel to the fourth direction are formed; a boundary region located between the second slit forming region and the third slit forming region; and The boundary region is n (n is an integer of 3 or more) boundary slits each extending substantially parallel to the pixel short-side direction, the n boundary slits being aligned along the pixel short-side direction; (n-1) first connecting portions, each of which is located between two adjacent boundary slits among the n boundary slits and connects the second slit forming region and the third slit forming region; (n-2) recessed patterns each located between two adjacent first connecting portions among the (n-1) first connecting portions, each including a first recessed portion formed so as to be recessed from a boundary slit located between the two first connecting portions toward the second slit formation region and a second recessed portion formed so as to be recessed toward the third slit formation region; (with the exception of a case where the boundary region includes a recessed pattern that is not located between two adjacent first connecting portions), A liquid crystal display device, wherein the plurality of second slits and the plurality of third slits are not continuous with the n boundary slits.

2. 2. The liquid crystal display device according to claim 1, wherein the distance from each of the (n-2) recessed patterns to each of the two first connecting portions adjacent to that recessed pattern is not less than 10 μm and not more than 30 μm.

3. 3. The liquid crystal display device according to claim 1, wherein the width of each of the (n-1) first connecting portions along the pixel short-side direction is not less than 2.5 μm and not more than 3.5 μm.

4. 3. The liquid crystal display device according to claim 1, wherein the length of each of the first recess and the second recess along the pixel longitudinal direction is 1.5 [mu]m or more.

5. 3. The liquid crystal display device according to claim 1, wherein the boundary region further includes two second connecting portions located at both ends of the pixel electrode in the pixel short-side direction, connecting the second slit formation region and the third slit formation region.

6. The liquid crystal display device according to claim 5 , wherein the width of each of the two second connecting portions along the pixel short-side direction is 6.0 μm or more.

7. a first substrate and a second substrate facing each other; a vertical alignment type liquid crystal layer provided between the first substrate and the second substrate, A liquid crystal display device having a plurality of pixels, the first substrate has pixel electrodes provided in the plurality of pixels, and a first alignment film provided between the pixel electrodes and the liquid crystal layer; the second substrate has a counter electrode facing the pixel electrode and a second alignment film provided between the counter electrode and the liquid crystal layer; each of the plurality of pixels has a first liquid crystal domain, a second liquid crystal domain, a third liquid crystal domain, and a fourth liquid crystal domain, which have mutually different reference alignment directions defined by the first alignment film and the second alignment film; when the longitudinal direction and the lateral direction of each of the plurality of pixels are referred to as a pixel longitudinal direction and a pixel lateral direction, respectively, and the reference alignment directions of the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are referred to as a first direction, a second direction, a third direction, and a fourth direction, respectively, the first direction, the second direction, the third direction, and the fourth direction form an angle with the pixel lateral direction that is approximately equal to an odd multiple of 45°, the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are arranged in this order along the pixel longitudinal direction, When an azimuth angle in the pixel short-side direction is 0°, the second direction and the third direction are approximately 135° and 315° directions, respectively, or approximately 45° and 225° directions, respectively; The pixel electrode is a first slit forming region, which is a region corresponding to the first liquid crystal domain and in which a plurality of first slits extending substantially parallel to the first direction are formed; a second slit forming region, which is a region corresponding to the second liquid crystal domain and in which a plurality of second slits extending substantially parallel to the second direction are formed; a third slit forming region, which is a region corresponding to the third liquid crystal domain and in which a plurality of third slits extending substantially parallel to the third direction are formed; a fourth slit forming region, which is a region corresponding to the fourth liquid crystal domain and in which a plurality of fourth slits extending substantially parallel to the fourth direction are formed; a boundary region located between the second slit forming region and the third slit forming region; and The boundary region is n (n is an integer of 3 or more) boundary slits each extending substantially parallel to the pixel short-side direction, the n boundary slits being aligned along the pixel short-side direction; (n-1) first connecting portions, each of which is located between two adjacent boundary slits among the n boundary slits and connects the second slit forming region and the third slit forming region; Including, a boundary slit located between two adjacent first connection portions among the n boundary slits has a first portion extending substantially parallel to the pixel short-side direction and a second portion extending substantially parallel to the pixel short-side direction and whose position in the pixel long-side direction is shifted from that of the first portion; the plurality of second slits and the plurality of third slits are not continuous with the n boundary slits, the second direction and the third direction are approximately 45° and 225° directions, respectively; the second portion is adjacent to the first portion in a direction of approximately 0°; A liquid crystal display device, wherein the second portion is positioned at an angle of 90° from the first portion in the pixel longitudinal direction.

8. A first substrate and a second substrate facing each other; a vertical alignment type liquid crystal layer provided between the first substrate and the second substrate, A liquid crystal display device having a plurality of pixels, the first substrate has pixel electrodes provided in the plurality of pixels, and a first alignment film provided between the pixel electrodes and the liquid crystal layer; the second substrate has a counter electrode facing the pixel electrode and a second alignment film provided between the counter electrode and the liquid crystal layer; each of the plurality of pixels has a first liquid crystal domain, a second liquid crystal domain, a third liquid crystal domain, and a fourth liquid crystal domain, which have mutually different reference alignment directions defined by the first alignment film and the second alignment film; when the longitudinal direction and the lateral direction of each of the plurality of pixels are referred to as a pixel longitudinal direction and a pixel lateral direction, respectively, and the reference alignment directions of the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are referred to as a first direction, a second direction, a third direction, and a fourth direction, respectively, the first direction, the second direction, the third direction, and the fourth direction form an angle with the pixel lateral direction that is approximately equal to an odd multiple of 45°, the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain are arranged in this order along the pixel longitudinal direction, When an azimuth angle in the pixel short-side direction is 0°, the second direction and the third direction are approximately 135° and 315° directions, respectively, or approximately 45° and 225° directions, respectively; The pixel electrode is a first slit forming region, which is a region corresponding to the first liquid crystal domain and in which a plurality of first slits extending substantially parallel to the first direction are formed; a second slit forming region, which is a region corresponding to the second liquid crystal domain and in which a plurality of second slits extending substantially parallel to the second direction are formed; a third slit forming region, which is a region corresponding to the third liquid crystal domain and in which a plurality of third slits extending substantially parallel to the third direction are formed; a fourth slit forming region, which is a region corresponding to the fourth liquid crystal domain and in which a plurality of fourth slits extending substantially parallel to the fourth direction are formed; a boundary region located between the second slit forming region and the third slit forming region; and The boundary region is n (n is an integer of 3 or more) boundary slits each extending substantially parallel to the pixel short-side direction, the n boundary slits being aligned along the pixel short-side direction; (n-1) first connecting portions, each of which is located between two adjacent boundary slits among the n boundary slits and connects the second slit forming region and the third slit forming region; Including, a boundary slit located between two adjacent first connection portions among the n boundary slits has a first portion extending substantially parallel to the pixel short-side direction and a second portion extending substantially parallel to the pixel short-side direction and whose position in the pixel long-side direction is shifted from that of the first portion; the plurality of second slits and the plurality of third slits are not continuous with the n boundary slits, the second direction and the third direction are approximately 135° and 315° directions, respectively; the second portion is adjacent to the first portion in a direction of approximately 0°; A liquid crystal display device, wherein the second portion is positioned 270° away from the first portion in the pixel longitudinal direction.

9. 9. The liquid crystal display device according to claim 7, wherein the length of each of the first portion and the second portion along the pixel short-side direction is 10 μm or more and 30 μm or less.

10. 9. The liquid crystal display device according to claim 7, wherein each of the (n-1) first connecting portions has a width in the pixel short-side direction of 2.5 μm to 3.5 μm.

11. 9. The liquid crystal display device according to claim 7, wherein the amount of positional deviation between the first portion and the second portion in the pixel longitudinal direction is 1.5 [mu]m or more.

12. 9. The liquid crystal display device according to claim 7, wherein the boundary region further includes two second connecting portions located at both ends of the pixel electrode in the pixel short-side direction, the second slit formation region and the third slit formation region being connected to each other.

13. The liquid crystal display device of claim 12 , wherein each of the two second connectors has a width of 6.0 μm or more along the pixel's shorter side.

14. 9. The liquid crystal display device according to claim 1, wherein each of the first alignment film and the second alignment film is a photo-alignment film.

15. 9. The liquid crystal display device according to claim 1, wherein in each of the first liquid crystal domain, the second liquid crystal domain, the third liquid crystal domain, and the fourth liquid crystal domain, a pretilt direction defined by the first alignment film and a pretilt direction defined by the second alignment film are substantially antiparallel to each other.

16. When each of the (n-1) first connection portions is referred to as a first orientation fixing pattern and each of the (n-2) recess patterns is referred to as a second orientation fixing pattern, 3. The liquid crystal display device according to claim 1, wherein the first alignment fixing pattern and the second alignment fixing pattern are alternately arranged in the boundary region, and the first alignment fixing pattern is arranged at the outermost side in the pixel short direction.

17. When each of the (n-1) first connecting portions is referred to as a first orientation fixing pattern, and a structure in which the first portion and the second portion of the boundary slit located between two adjacent first connecting portions among the n boundary slits are misaligned is referred to as a second orientation fixing pattern, 9. The liquid crystal display device according to claim 7, wherein the first alignment fixing pattern and the second alignment fixing pattern are alternately arranged in the boundary region, and the first alignment fixing pattern is arranged on the outermost side in the pixel short side direction.

Images