JP2014066834A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent decrease in transmittance or decrease in display qualities caused by positional deviation of upper and lower substrates in a liquid crystal display device using an electrode having an opening.SOLUTION: The liquid crystal display device includes a first substrate 11 and a second substrate 12 disposed to oppose to each other, a first electrode 13 having a plurality of openings 18 and disposed on the first substrate, a second electrode 14 disposed on the second substrate, and a liquid crystal layer 17 disposed between the first substrate and the second substrate, in which a display section is defined in a region where the first electrode and the second electrode overlap. The plurality of openings each have a shape in a plan view including a first portion extending in a first direction and one or more second portions extending in a second direction substantially orthogonal to the first direction in such a manner that the second portion partially overlaps the first portion approximately at the center of the first portion in the first direction; and the openings are periodically arranged in a checkered pattern in the first direction and in the second direction.

Description

  The present invention relates to a liquid crystal display device including an electrode having an opening.

  As one technique for improving the viewing angle characteristics of a liquid crystal display device, a plurality of openings (slits) are provided in each of the upper and lower electrodes that are opposed to each other with the liquid crystal layer interposed therebetween, so that a liquid crystal layer is applied when a voltage is applied to the liquid crystal layer. There is known a multi-domain alignment technique in which alignment domains of liquid crystal molecules are divided in a plurality of directions within one pixel. For example, in Japanese Patent No. 4107978 (Patent Document 1), liquid crystal at the time of voltage application is arranged by alternately arranging the openings of the upper electrode and the openings of the lower electrode in the short side direction in a plan view. There is disclosed a liquid crystal display device (liquid crystal display element) in which two alignment domains in which the alignment directions of liquid crystal molecules are 180 ° different from each other are obtained in a layer. In Japanese Patent No. 4846402 (Patent Document 2), voltage is applied by setting the longitudinal direction of each opening in two different directions for each of the opening of the upper electrode and the opening of the lower electrode. There is disclosed a liquid crystal display device (liquid crystal display element) in which four alignment domains in which the alignment directions of liquid crystal molecules are 90 ° different from each other are obtained in the liquid crystal layer.

  Further, in Japanese Patent No. 4884176 (Patent Document 3), when the longitudinal direction of each opening is set in two different directions for each of the opening of the upper electrode and the opening of the lower electrode, the plan view is shown. In this embodiment, the openings of the upper electrode and the opening of the lower electrode are alternately arranged with a half-pitch shift, so that the orientation directions of the liquid crystal molecules are different from each other by 90 ° in the liquid crystal layer when a voltage is applied. A liquid crystal display device (liquid crystal display element) in which an alignment domain is obtained is disclosed. According to such a configuration, the distance between adjacent openings can be increased as compared with the liquid crystal display device disclosed in Patent Document 2, so that the electrical resistance of the electrode is increased and the electrode is disconnected. It is possible to greatly reduce the probability of occurrence.

  By the way, generally, when manufacturing a liquid crystal display device, the alignment accuracy when the upper and lower substrates are overlapped is relatively low. Therefore, it is difficult to superimpose the upper and lower substrates while accurately aligning the positions of the openings provided in the respective electrodes of the upper and lower substrates as described above. If the positional relationship between the upper and lower substrates having openings in the electrodes is shifted, it may not be possible to obtain a good viewing angle characteristic intended by design. In particular, when an opening arranged in a checkered pattern as shown in Patent Document 2 described above is used, an unintended dark region is generated around the opening, resulting in a decrease in transmittance and display quality. There is a concern to invite.

Japanese Patent No. 4107978 Japanese Patent No. 4846402 Japanese Patent No. 4884176

  A specific aspect according to the present invention is to provide a technique capable of preventing a decrease in transmittance and a decrease in display quality due to a positional shift between upper and lower substrates in a liquid crystal display device using an electrode having an opening. One of the purposes.

  A liquid crystal display device according to one embodiment of the present invention includes (a) a first substrate and a second substrate which are disposed to face each other, (b) a first electrode provided on the first substrate, and (c) a plurality of openings. A second electrode provided on the second substrate; and (d) a liquid crystal layer disposed between the first substrate and the second substrate, and (e) a first electrode and a second electrode, (F) Each of the plurality of openings has a first portion extending in the first direction and a first portion extending in the second direction substantially orthogonal to the first direction in plan view. The two or more second parts have a shape in which a part of the first part is superposed on the approximate center in the first direction of the second part, and each of the first direction and the second direction The liquid crystal display device is periodically arranged in a checkered pattern.

  According to the above configuration, it is possible to prevent the first electrode from being provided with an opening. Therefore, the transmittance and display quality are deteriorated due to the positional deviation between the first substrate and the second substrate as described above. It becomes possible to prevent.

  In the above liquid crystal display device, each of the plurality of openings can be formed in a T shape, an inverted T shape, a cross shape, or an I shape, for example, in plan view. In this case, as the plurality of openings, only one of a T shape, an inverted T shape, a cross shape, or an I shape may be used. In addition, as the plurality of openings, any two or more of a T shape, an inverted T shape, a cross shape, or an I shape may be used in combination.

  In the above liquid crystal display device, the second electrode has a plurality of rectangular regions periodically arranged in the display unit in plan view, and each of the plurality of rectangular regions has four sides that define the rectangular region. The first electrode has a plurality of circular or substantially rectangular second openings, and each of the plurality of second openings includes a plurality of openings in plan view. It is also preferable that they are arranged so as to overlap with any of the rectangular regions.

  Thereby, it is possible to improve the alignment uniformity while suppressing the influence of spacers and foreign matters arranged in the liquid crystal layer.

FIG. 1A is a diagram showing the electrode structure of the lower substrate used for the simulation analysis, and FIG. 1B is a diagram showing the electrode structure of the upper substrate used for the simulation analysis. FIG. 1C is a diagram showing the calculation result of the oriented structure. FIG. 2A is a diagram showing the electrode structure of the lower substrate used for the simulation analysis, and FIG. 2B is a diagram showing the electrode structure of the upper substrate used for the simulation analysis. FIG. 2C is a diagram showing the calculation result of the oriented structure. FIG. 3 is a cross-sectional view showing the basic structure of the liquid crystal display device of the first embodiment. 4A is a diagram showing the structure of the second electrode of the second substrate used for the simulation analysis, and FIG. 4B is a diagram showing the structure of the first electrode of the first substrate used for the simulation analysis. is there. FIG. 4C is a diagram showing the calculation result of the orientation texture. FIG. 5A is a plan view showing an example of the second electrode (segment electrode), FIG. 5B is a plan view showing an example of the first electrode (common electrode), and FIG. It is a top view which shows an example of the outline shape of a display part, and the opening part arrange | positioned in a 2nd electrode, FIG.5 (D) shows the state which accumulated the opening part arrange | positioned in a 1st electrode, a 2nd electrode, and a 2nd electrode. It is an example of the top view shown. 6A is a plan view illustrating an example of each opening in the second electrode of the X portion (see FIG. 5D) of the illustrated display portion, and FIG. 6B is an X of the illustrated display portion. It is a top view which shows another example of each opening part in the 2nd electrode of a part (refer FIG.5 (D)). FIG. 7A is a plan view illustrating an example in which each opening is provided in the first electrode of the X portion (see FIG. 5D) of the illustrated display portion, and FIG. 7B is an illustrated display. It is a top view which shows another example in the case of providing each opening part in the 1st electrode of the X part (refer FIG.5 (D)) of a part. FIG. 8 is a plan view illustrating an example of each opening in the second electrode of the X portion (see FIG. 5D) of the illustrated display portion. FIG. 9A shows the structure of the second electrode of the second substrate used for the simulation analysis. FIG. 9B is a diagram showing the calculation result of the oriented structure. FIG. 10 is a plan view illustrating an example of each opening in the second electrode of the X portion (see FIG. 5D) of the illustrated display unit. FIG. 11A shows the structure of the second electrode of the second substrate used for the simulation analysis. FIG. 11B is a diagram showing the calculation result of the oriented structure. FIG. 12 is a plan view illustrating an example of each opening in the second electrode of the X portion (see FIG. 5D) of the illustrated display unit. FIG. 13A shows the structure of the second electrode of the second substrate used for the simulation analysis. FIG. 13B is a diagram showing the calculation result of the oriented structure.

  Embodiments of the present invention will be described below with reference to the drawings.

(Reference example)
As a reference example for examining the influence of the positional deviation between the upper and lower substrates, as shown in Patent Document 2 described above, when a voltage is applied to a liquid crystal display device in which each of the electrodes on the upper and lower substrates is provided with a cross-shaped opening. The orientational texture of this was analyzed by simulation. In the liquid crystal display device of the reference example, the openings are regularly arranged in the up, down, left, and right directions, and the openings of the upper substrate and the openings of the lower substrate are arranged with a shift of about ½ pitch. Has been. The conditions for simulation analysis are as follows (the same applies to the embodiments described later). This analysis was carried out using LCD Master 3D version 7 which is a 3D analysis simulator manufactured by Shintech. The calculation area was set to 160 × 160 μm, the in-plane division number was set to 40 × 40 mesh, the cell thickness was set to 4 μm, and the division number in the thickness direction was set to 30. Each structure of the upper electrode and the lower electrode in the 160 × 160 region was defined as a periodic structure in the vertical and horizontal directions. The liquid crystal layer was assumed to have a completely vertical alignment with a pretilt angle of 90 ° when no voltage was applied, and a liquid crystal material having a refractive index anisotropy Δn of approximately 0.09 and a negative dielectric anisotropy was assumed. By applying 4 V to the upper substrate electrode (common electrode) and 0 V to the lower substrate electrode (segment electrode), an alignment texture image was calculated when the alignment state of the liquid crystal layer was in a steady state. The front polarizing plate was arranged in a crossed Nicol arrangement of 45 ° clockwise with respect to the left and right direction of the electrode, and the back polarizing plate was 45 ° counterclockwise.

  FIG. 1A is a diagram showing the electrode structure of the lower substrate used for the simulation analysis, and FIG. 1B is a diagram showing the electrode structure of the upper substrate used for the simulation analysis. The opening provided in each electrode is formed in a cross shape in which a portion extending in the up-down direction and a portion extending in the left-right direction intersect each other near the center of each other. The width of each part of each opening is approximately 10 μm, the length of the long side of the part extending in the vertical direction is approximately 90 μm, the distance between adjacent openings in the vertical direction is approximately 20 μm, and extends in the left-right direction. The long side length of the existing part was about 70 μm, and the distance between openings adjacent in the left-right direction was about 30 μm. The center of gravity of the cross-shaped opening is regularly arranged at a pitch of about 105 μm in the left-right direction and about 110 μm in the up-down direction. FIG. 1C is a diagram showing the calculation result of the oriented structure. In each electrode of the upper and lower substrates, a plurality of rectangular regions whose four sides are in contact with the openings are demarcated by the cross-shaped openings that are displaced by approximately ½ pitch in the two directions of the upper and lower sides and the left and right sides. Four of these rectangular regions will be defined around each opening. As shown in the figure, the absorption axis of the polarizing plate in each rectangular region and the liquid crystal molecules aligned in the direction close thereto are visualized as dark regions. In the meantime, a dark region, that is, a domain boundary region in which a continuous orientation change is obtained is observed. Therefore, it is considered that the liquid crystal molecules are aligned at all 360 ° within each rectangular region.

  Next, as an example of the case where the positional accuracy at the time of bonding the upper and lower substrates is not sufficient, a simulation analysis of the alignment structure was performed in the same manner as described above for the case where the upper substrate was superimposed with a displacement of about 20 μm in the right direction. FIG. 2A is a diagram showing the electrode structure of the lower substrate used for the simulation analysis, and FIG. 2B is a diagram showing the electrode structure of the upper substrate used for the simulation analysis. The electrode structure is defined under the same conditions as described above except that the position of the upper substrate is shifted. FIG. 2C is a diagram showing the calculation result of the oriented structure. Compared with the case where the alignment of the upper and lower substrates is good (see FIG. 1C above), the areas of the left two rectangular regions and the two right rectangular regions of one opening arranged on the electrodes are unequal. For this reason, the areas of the four main alignment regions in each rectangular region are not uniform, and the dark regions clearly increase. As a result, the transmittance is reduced and the uniformity of the in-plane alignment structure is impaired. Therefore, when observing the appearance, particularly when observing at a deep angle in the polar angle direction with respect to the normal to the display surface of the liquid crystal display device Display unevenness occurs.

  An embodiment of a liquid crystal display device capable of preventing a decrease in transmittance and a decrease in display quality due to such positional deviation between the upper and lower substrates will be described in detail below.

(First embodiment)
FIG. 3 is a cross-sectional view showing the basic structure of the liquid crystal display device of the first embodiment. The liquid crystal display device includes a first substrate 11 and a second substrate 12 which are disposed to face each other, a first electrode 13 provided on the first substrate 11, a second electrode 14 provided on the second substrate 12, A liquid crystal layer 17 disposed between the first substrate 11 and the second substrate 12 is provided as a basic configuration. For example, the liquid crystal display device according to the present embodiment is configured so that a region where electrodes overlap with each other forms a character or design to be displayed, and can basically display only a predetermined character or the like. This is a segment display type liquid crystal display device in which an area ratio of about 50% or less contributes to the display of characters and the like. Note that the liquid crystal display device may be a dot matrix display type in which a plurality of pixels are arranged in a matrix, or may be a mixture of a segment display type and a dot matrix type.

  The first substrate 11 and the second substrate 12 are transparent substrates such as a glass substrate and a plastic substrate, respectively. As illustrated, the first substrate 11 and the second substrate 12 are bonded to each other with a predetermined gap (for example, about 4 μm).

  The first electrode 13 is provided on one surface side of the first substrate 11. Similarly, the second electrode 14 is provided on one surface side of the second substrate 12. The first electrode 13 and the second electrode 14 are each configured by appropriately patterning a transparent conductive film such as indium tin oxide (ITO), for example. The second electrode 14 has a plurality of openings 18, but the first electrode 13 has no openings. Each opening 18 has a plan view shape such as a cross shape, a T shape, and an inverted T shape.

  The first alignment film 15 is provided on one surface side of the first substrate 11 so as to cover the first electrode 13. The second alignment film 16 is provided on one surface side of the second substrate 12 so as to cover the second electrode 14. As the first alignment film 15 and the second alignment film 16, vertical alignment films that restrict the alignment state of the liquid crystal layer 17 to the vertical alignment are used. Each alignment film is not subjected to uniaxial alignment treatment such as rubbing treatment.

  The liquid crystal layer 17 is provided between the first substrate 11 and the second substrate 12. In the present embodiment, the liquid crystal layer 17 is configured using a liquid crystal material having a negative dielectric anisotropy Δε. The refractive index anisotropy Δn of the liquid crystal material is, for example, about 0.09. The thick line shown in the liquid crystal layer 17 schematically shows the alignment direction of the liquid crystal molecules in the liquid crystal layer 17. The liquid crystal layer 17 of the present embodiment is set to a vertical alignment in which the alignment direction of liquid crystal molecules when no voltage is applied is perpendicular to the substrate surfaces of the first substrate 11 and the second substrate 12.

  The first polarizing plate 21 is disposed outside the first substrate 11. Similarly, the second polarizing plate 22 is disposed outside the second substrate 12. The first polarizing plate 21 and the second polarizing plate 22 are arranged so that their absorption axes are substantially orthogonal to each other. In addition, an optical compensation plate such as a C plate may be appropriately disposed between each polarizing plate and each substrate. For example, in the present embodiment, optical compensation plates 23 and 24 are disposed between the first substrate 11 and the first polarizing plate 21 and between the second substrate 12 and the second polarizing plate 22, respectively.

  Next, the result of simulation analysis of a liquid crystal display device in which the opening provided in the second electrode has a cross shape will be described. FIG. 4A is a diagram showing the structure of the first electrode of the first substrate used in the simulation analysis, and FIG. 4B is a diagram showing the structure of the second electrode of the second substrate used in the simulation analysis. is there. In the above-described reference example, the upper and lower electrodes are each provided with a cross-shaped opening, but in the first embodiment, only the second electrode of the second substrate, which is the upper substrate, is provided with a cross-shaped opening. No opening is provided in the first electrode of the first substrate, which is the substrate. As shown in the figure, the openings of the second electrode are arranged in a checkered pattern in the two directions, up and down and left and right. The width of each part of each opening is approximately 10 μm, the length of the long side of the part extending in the vertical direction is approximately 80 μm, the distance between adjacent openings in the vertical direction is approximately 25 μm, and extends in the left-right direction. The long side length of the existing part was about 80 μm, and the distance between openings adjacent in the left-right direction was about 23 μm. Each opening is formed in a cross shape in which a portion extending in the vertical direction and a portion extending in the left-right direction intersect each other at approximately 90 °.

  FIG. 4C is a diagram showing the calculation result of the orientation texture. It can be seen that a pattern very similar to the orientation structure (see FIG. 1C) when the upper and lower substrates are not misaligned in the reference example described above is shown. That is, in the four rectangular regions adjacent to one opening, in addition to the four main alignment regions that are aligned in each of the upper, lower, left, and right directions, a region in which the alignment direction, which is a dark region therebetween, continuously changes is observed. It is considered that liquid crystal molecules are aligned in the 360 ° direction. On the other hand, in the region where the electrodes between the openings adjacent to each other in the upper, lower, left and right directions are not opened, that is, in the vicinity of the two corners in the rectangular region adjacent to one opening, the orientation structure slightly different from the reference example is Has been obtained. However, in this part, the tendency to decrease the dark area by arranging the distance between the openings as close as possible was obtained by another simulation analysis. In addition, although the length of one side of one rectangular area is about 50 μm in the simulation analysis, a good alignment state can be obtained if one side is about 100 μm or less. In the above description, the rectangular area is analyzed as a substantially square, but the lengths of the sides in the vertical direction and the horizontal direction may be different.

  Next, as an example, a description will be given of the case where the opening as described above is provided in the electrode pattern constituting the display unit for displaying the English letter “S”. FIG. 5A is a plan view showing an example of the second electrode (segment electrode), FIG. 5B is a plan view showing an example of the first electrode (common electrode), and FIG. FIG. 5D is a plan view showing an example of the contour shape of the display portion and an opening portion arranged in the second electrode, and FIG. 5D shows a state in which the opening portions arranged in the first electrode, the second electrode, and the second electrode are overlapped. It is an example of the top view shown. As shown in FIG. 5A, the second electrode 14 has a plan view shape that is substantially close to the English letter “S”. A lead wire 31 and an external extraction electrode 32 are provided on the second electrode 14. The external extraction electrode 32 is for connecting to an external circuit (not shown). The lead wire 31 is used to connect the external extraction electrode 32 and the first electrode 13. Although not shown, a lead-out line for connecting to the second electrode 14 of another display unit is also provided below the second electrode 14. As shown in FIG. 5A, it can be seen that most of the second electrode 14 corresponds to the outer edge portion of the display portion (see FIG. 5C). On the other hand, as shown in FIG. 5B, the first electrode 13 is provided in a wide range that covers almost the entire display portion, and is used for mutual connection with the first electrodes of other display portions. Lead lines 33 are provided on the left and right, respectively. As shown in FIG. 5D, the first electrode 13 has a structure that overlaps with the entire second electrode 14 and protrudes outward from the entire display unit. Forming a part of the outer edge.

  6A is a plan view illustrating an example of each opening in the second electrode of the X portion (see FIG. 5D) of the illustrated display portion, and FIG. 6B is an X of the illustrated display portion. It is a top view which shows another example of each opening part in the 2nd electrode of a part (refer FIG.5 (D)). In the example shown in FIG. 6A, there are at least two edges of the display portion with respect to the left-right direction of the opening 18, but the opening 18 is in a predetermined area inside the right edge, which is one of them. Adopted a structure that does not place. Specifically, in the illustrated example, a predetermined area having a width of about 30 μm is provided on the inner side from the right edge, and the opening 18 is not disposed in this predetermined area. However, the opening 18 is not disposed only in a region where the first electrode 13 protrudes outside the edge of the display unit from the second electrode 14. The second electrode 14 of the present example has a lead line in the vertical direction, and extends near the edge of the display portion from the first electrode 13 near the upper side and the lower side of the display portion “S”. You may arrange | position the opening part 18 to the edge of a display part. As described above, by not providing the opening 18 in the predetermined region inside the edge of the display unit, even if the distance between the adjacent opening 18 is short, the electrical power of the first electrode 13 can be reduced. It is possible to prevent the resistance from increasing to cause display unevenness and the adjacent openings to be joined to cause disconnection. As shown in FIG. 6B, in a region where the first electrode 13 protrudes outward from the edge of the display unit rather than the second electrode 14, an opening is provided in a predetermined range from the edge of the display unit to the inside. It is good also as a structure which does not provide 18 at all.

  In the embodiment described above, each opening 18 is provided only in the second electrode 14, but each opening 18 may be provided only in the first electrode 13. In this case, it is considered necessary to design a pattern in consideration of the positional deviation between the first electrode 13 and the second electrode 14. FIG. 7A is a plan view illustrating an example in which each opening is provided in the first electrode of the X portion (see FIG. 5D) of the illustrated display portion, and FIG. 7B is an illustrated display. It is a top view which shows another example in the case of providing each opening part in the 1st electrode of the X part (refer FIG.5 (D)) of a part. As shown in FIG. 7A, in the portion where the first electrode 13 protrudes outward from the edge of the display portion rather than the second electrode 14, the opening 18 is provided in a predetermined range outward from the edge of the display portion. Due to the arrangement structure, even if a position shift occurs, an opening is arranged in almost all areas in the display unit, and display unevenness near the edge of the display unit due to the absence of the opening can be suppressed. it is conceivable that. Although not shown, the upper side and the lower side of the display portion “S” where the second electrode 14 protrudes from the edge of the display portion as compared with the first electrode 13 are as shown in FIG. The opening 18 may not be provided in a predetermined range outside the edge of the display unit.

  Further, as shown in FIG. 7B, in each of the rectangular regions 34 arranged with the openings 18 in contact with the four sides, for example, a circular or substantially rectangular opening 19 may be further provided at the approximate center thereof. . In this case, for example, each opening 19 can be provided in the first electrode 13, and each opening 18 can be provided in the second electrode 14. By providing such an opening 19, the position of the central portion of the cross-shaped dark region is stable and more uniform orientation without being affected by spacers or foreign matters arranged in the plane in each rectangular region. Control can be realized.

  In the first embodiment described above, the longitudinal direction of each opening 18 is set in each of the up, down, left and right directions, but this is not restrictive. The longitudinal direction of each opening 18 may be set to approximately 45 ° clockwise and approximately 45 ° counterclockwise with respect to the left-right direction.

(Second Embodiment)
As a structure that can obtain the same effects as those of the first embodiment described above, each opening can be formed in a T shape.

  FIG. 8 is a plan view illustrating an example of each opening in the second electrode of the X portion (see FIG. 5D) of the illustrated display portion. Each opening 18 shown in FIG. 8 has a portion extending in the left-right direction and a portion extending in the up-down direction, and a portion extending in the up-down direction substantially at the center in the longitudinal direction of the portion extending in the left-right direction. Are formed in a T-shape formed by joining one end sides of the two. And these opening parts 18 are arrange | positioned periodically and in a checkered pattern with respect to each direction of up and down, left and right. As in the first embodiment described above, an opening may not be provided in a predetermined region inside the edge of the display unit, or a circular or substantially rectangular opening may be provided in the first electrode 13 as described above. These openings may be disposed in the rectangular region 34 in plan view (the same applies to the following embodiments).

  Next, the results of simulation analysis of a liquid crystal display device in which the opening provided in the second electrode has a T shape will be described. FIG. 9A shows the structure of the second electrode of the second substrate used for the simulation analysis. The structure of the first electrode of the first substrate is the same as that of the first embodiment (see FIG. 4A). As shown in the figure, the T-shaped openings of the second electrode are arranged in a checkered pattern in the vertical and horizontal directions. Four rectangular regions having openings on four sides are formed on the left and right sides of a portion extending in the vertical direction of one opening. The width of each part of each opening is about 10 μm, the long side length of the part (horizontal bar) extending in the left-right direction is about 65 μm, and the long side length of the part (vertical bar) extending in the vertical direction Is approximately 85 μm, the distance between the horizontal bars of the adjacent openings is approximately 40 μm, and the distance between the vertical bars and the horizontal bars of the other openings is approximately 15 μm. Further, the arrangement period in the vertical direction of the opening is about 110 μm, and the arrangement period in the left-right direction is about 95 μm.

  FIG. 9B is a diagram showing the calculation result of the oriented structure. Since cross-shaped dark regions are observed in the four rectangular regions adjacent to the vertical bars of the openings, the four main alignment regions and the boundary in which the alignment direction continuously changes in the rectangular regions. It can be seen that there is a region, and the liquid crystal alignment direction is 360 ° within the rectangular region. Although the orientation patterns in the four rectangular areas are different, the rectangular areas are arranged minutely and periodically, so that it is considered that they are observed uniformly in appearance observation. The size of each rectangular region is approximately 50 μm square in the above-described simulation analysis. However, if one side is approximately 100 μm or less, a good alignment state can be obtained. In the above description, the rectangular area is analyzed as a substantially regular square, but the lengths of the sides in the vertical direction and the horizontal direction may be different.

  In the second embodiment described above, the longitudinal direction of each opening 18 is set in each of the upper, lower, left and right directions, but this is not restrictive. The longitudinal direction of each opening 18 may be set to approximately 45 ° clockwise and approximately 45 ° counterclockwise with respect to the left-right direction.

(Third embodiment)
In the second embodiment described above, the liquid crystal display device in which the T-shaped openings are arranged in a checkered pattern in the vertical and horizontal directions has been described. However, the T-shaped opening and the inverted T-shaped opening are described. May be alternately arranged in a checkered pattern.

  FIG. 10 is a plan view illustrating an example of each opening in the second electrode of the X portion (see FIG. 5D) of the illustrated display unit. Each opening 18 shown in FIG. 10 has a T-shape and a reverse T-shape. And these opening parts 18 are arrange | positioned periodically and in a checkered pattern with respect to each direction of up and down, left and right. Specifically, each opening 18 is arranged so that the vertical bar of the inverted T-shaped opening 18 is positioned at the approximate center between the horizontal bars of the two T-shaped opening 18. . Further, the T-shaped opening 18 and the inverted T-shaped opening 18 have the same width and length at each part.

  Next, the result of simulation analysis of a liquid crystal display device in which the opening provided in the second electrode has a T shape and an inverted T shape will be described. FIG. 11A shows the structure of the second electrode of the second substrate used for the simulation analysis. The structure of the first electrode of the first substrate is the same as that of the first embodiment (see FIG. 4A). As shown in the figure, the openings of the second electrode are regularly arranged in a checkered pattern in the vertical and horizontal directions. Four rectangular regions having openings on four sides are formed on the left and right sides of a portion extending in the vertical direction of one opening. The width of each part of each opening is approximately 10 μm, the long side length of the part (horizontal bar) extending in the left-right direction is approximately 75 μm, and the long side length of the part (vertical bar) extending in the vertical direction Is approximately 85 μm, the distance between the horizontal bars of the adjacent openings is approximately 30 μm, and the distance between the vertical bars and the horizontal bars of the other openings is approximately 15 μm. Further, the arrangement period in the vertical direction of the opening is about 100 μm, and the arrangement period in the left-right direction is about 95 μm.

  FIG. 11B is a diagram showing the calculation result of the oriented structure. Since cross-shaped dark regions are observed in the four rectangular regions adjacent to the vertical bars of the openings, the four main alignment regions and the boundary in which the alignment direction continuously changes in the rectangular regions. It can be seen that there is a region, and the liquid crystal alignment direction is 360 ° within the rectangular region. Although the orientation patterns in the four rectangular areas are different, the rectangular areas are arranged minutely and periodically, so that it is considered that they are observed uniformly in appearance observation. The size of each rectangular region is approximately 50 μm square in the above-described simulation analysis. However, if one side is approximately 100 μm or less, a good alignment state can be obtained. In the above description, the rectangular area is analyzed as a substantially regular square, but the lengths of the sides in the vertical direction and the horizontal direction may be different.

  In the above-described third embodiment, the longitudinal direction of each opening 18 is set in the vertical and horizontal directions, but this is not restrictive. The longitudinal direction of each opening 18 may be set to approximately 45 ° clockwise and approximately 45 ° counterclockwise with respect to the left-right direction.

(Fourth embodiment)
In the first and second embodiments described above, the case of using openings having the same shape is shown, and in the third embodiment, the case of using openings having shapes that are upside down with respect to each other is shown, but openings having different shapes are used. May be.

  FIG. 12 is a plan view illustrating an example of each opening in the second electrode of the X portion (see FIG. 5D) of the illustrated display unit. Each opening 18 shown in FIG. 12 is formed in a cross shape and in a shape in which upper and lower horizontal bars of the English letter “I” are elongated (hereinafter simply referred to as “I-shape”). There is something. And each opening part 18 is arrange | positioned periodically and checkered with respect to each direction of up and down, left and right. In detail, each opening 18 has a vertical bar of I-shaped opening 18 positioned substantially at the center between the horizontal bars of two cross-shaped openings 18, and two I-shaped openings. The vertical bars of the cross-shaped opening 18 are arranged so as to be positioned approximately at the center between the horizontal bars of the part 18. The cross-shaped opening 18 and the I-shaped opening 18 have the same width and length at each part.

  Next, a result of simulation analysis of a liquid crystal display device in which the opening provided in the second electrode has a cross shape and an I shape will be described. FIG. 13A shows the structure of the second electrode of the second substrate used for the simulation analysis. The structure of the first electrode of the first substrate is the same as that of the first embodiment (see FIG. 4A). As shown in the figure, the openings of the second electrode are regularly arranged in a checkered pattern in the vertical and horizontal directions. Four rectangular regions having openings on four sides are formed on the left and right sides of a portion extending in the vertical direction of one opening. The width of each part of each opening is approximately 10 μm, the part of the cross-shaped opening (horizontal bar) extending in the left-right direction is approximately 75 μm and the part extending vertically (vertical bar) ) Has a long side length of about 170 μm, the distance between the horizontal bars of adjacent cross-shaped openings is about 30 μm, and the long side of the portion (horizontal bar) extending in the left-right direction of the I-shaped opening The length of the part (vertical bar) extending in the vertical direction is approximately 75 μm, the length of the long side is approximately 100 μm, and the distance between the horizontal bars of the adjacent I-shaped openings is approximately 30 μm. The distance between the vertical bar of the opening and the horizontal bar of the I-shaped opening adjacent thereto is approximately 15 μm.

  FIG. 13B is a diagram showing the calculation result of the oriented structure. Since cross-shaped dark areas are observed in the four rectangular areas adjacent to the vertical bars of the I-shaped opening, the four main alignment areas and the alignment directions between them are continuous in the rectangular area. It can be seen that there is a boundary region that changes to, and the liquid crystal alignment direction is oriented to 360 ° within the rectangular region. Although the orientation patterns in the four rectangular areas are different, the rectangular areas are arranged minutely and periodically, so that it is considered that they are observed uniformly in appearance observation. The size of each rectangular region is approximately 50 μm square in the above-described simulation analysis. However, if one side is approximately 100 μm or less, a good alignment state can be obtained. In the above description, the rectangular area is analyzed as a substantially regular square, but the lengths of the sides in the vertical direction and the horizontal direction may be different.

  In the above-described third embodiment, the longitudinal direction of each opening 18 is set in the vertical and horizontal directions, but this is not restrictive. The longitudinal direction of each opening 18 may be set to approximately 45 ° clockwise and approximately 45 ° counterclockwise with respect to the left-right direction.

  In addition, this invention is not limited to the content of embodiment mentioned above, In the range of the summary of this invention, it can change and implement variously. For example, in each of the embodiments described above, the structure in which the rectangular region provided in the second electrode is periodically arranged in the vertical and horizontal directions is shown, but this is not restrictive. For example, it may be a checkered arrangement in which the center of gravity of the rectangular area is shifted by about 1/2 pitch with respect to the adjacent row for each row.

DESCRIPTION OF SYMBOLS 11: 1st board | substrate 12: 2nd board | substrate 13: 1st electrode 14: 2nd electrode 15: 1st orientation film 16: 2nd orientation film 17: Liquid crystal layer 18, 19: Opening part 21: 1st polarizing plate 22: Second polarizing plate 23, 24: Optical compensation plate 31, 33: Lead wire 32: External extraction electrode 34: Rectangular region

Claims (5)

A first substrate and a second substrate disposed opposite to each other;
A first electrode provided on the first substrate;
A plurality of openings, a second electrode provided on the second substrate;
A liquid crystal layer disposed between the first substrate and the second substrate;
Including
A display portion is defined in a region where the first electrode and the second electrode overlap;
Each of the plurality of openings includes a first part extending in a first direction and one or more second parts extending in a second direction substantially orthogonal to the first direction in the plan view. Of the first part of the first part of the first part of the first part of the first part of the first part and the second direction of the first part and the second direction are arranged in a checkered pattern periodically. Being
Liquid crystal display device.   2. The liquid crystal display device according to claim 1, wherein each of the plurality of openings has a T shape, an inverted T shape, a cross shape, or an I shape in plan view.   The liquid crystal display device according to claim 2, wherein the plurality of openings are any one of the T shape, the inverted T shape, the cross shape, or the I shape.   The liquid crystal display device according to claim 2, wherein the plurality of openings are any two or more of the T shape, the inverted T shape, the cross shape, or the I shape. The second electrode has a plurality of rectangular regions that are periodically arranged in the display unit in a plan view, and each of the plurality of rectangular regions has four sides that define the rectangular region. In contact with any part of the
The first electrode has a plurality of circular or substantially rectangular second openings,
Each of the plurality of second openings is disposed so as to overlap with any of the plurality of rectangular regions in plan view.
The liquid crystal display device according to claim 1.