JP2014182262A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display element capable of easily specifying the direction of inclined alignment by applying a voltage, of a liquid crystal oriented vertically.SOLUTION: A liquid crystal display element 1 includes: a first substrate on which a first electrode 2 is arranged; a second substrate on which a second electrode 4 is arranged; and a liquid crystal layer that is disposed between substrates, and of which an orientation of a liquid crystal is vertical when no voltage is applied. The first and second electrodes 2 and 4 include a plurality of first openings 8 and a plurality of second openings 9 that are arranged in a regular manner in a first direction, respectively. Each of the first and , and parallel two sides are parallel to the first direction. Opposing sides among adjacent sides in the first direction are parallel to each other. The first and second openings 8 and 9 are out of alignment in a second direction perpendicular to the first direction in planar view and arranged so as to partially overlap each other.

Description

  The present invention relates to a liquid crystal display element.

  The liquid crystal display element includes a transmission type and a reflection type. For example, in the case of a transmission type, a transparent first substrate disposed on the viewer side (also referred to as a viewing side) and the first substrate A transparent second substrate disposed opposite to the viewer (also referred to as the anti-viewing side) and sandwiching a liquid crystal layer between the first substrate and the second substrate Configured.

  The liquid crystal layer can be formed using, for example, nematic liquid crystal (hereinafter also referred to as nematic liquid crystal). Then, an electrode made of a transparent conductive material such as ITO (Indium Tin Oxide) with necessary patterning is provided on the inner surface on the liquid crystal layer side of the first substrate and / or the second substrate. be able to. A liquid crystal alignment film that realizes uniform initial alignment of the liquid crystal in the liquid crystal layer can be provided on the surface of the electrode on each substrate in contact with the liquid crystal layer. A pair of polarizing plates can be arranged on the viewer side and the opposite side with both the first substrate and the second substrate sandwiching the liquid crystal layer interposed therebetween. In the liquid crystal display device having such a configuration, the liquid crystal of the liquid crystal layer changes its orientation from the initial alignment state in accordance with the electric field applied to the liquid crystal layer using the electrode, and the light transmitted through the liquid crystal layer is controlled. Made.

  Liquid crystal display elements are classified into several modes (types) based on the initial alignment state of the liquid crystal in the liquid crystal layer and the operation when an electric field is applied. For example, there is a liquid crystal display element in which the liquid crystal in the liquid crystal layer when no voltage is not applied and no electric field is applied has a vertical alignment that is vertical or substantially vertical to the substrate surface. Such a liquid crystal display element is referred to as a VA (Vertical Alignment) type liquid crystal display element.

  In the VA liquid crystal display element, a liquid crystal having negative dielectric anisotropy is used for forming a liquid crystal layer. On the first and second substrates, polarizing plates are respectively disposed on the viewing side and the non-viewing side so as to sandwich the first and second substrates. That is, a pair of polarizing plates is usually arranged so as to form a crossed Nicol with the liquid crystal layer sandwiched between the first and second substrates interposed therebetween.

  Electrodes are provided on the inner surfaces of the first and second substrates on the liquid crystal layer side. The electrodes of the first and second substrates constitute each pixel with a liquid crystal layer interposed therebetween. When a voltage is applied to the liquid crystal layer of the pixel using the electrode, the liquid crystal in the liquid crystal layer tilts and changes its orientation, and the liquid crystal layer tends to be perpendicular to the formed electric field, that is, parallel to the substrate. (For example, refer to Patent Document 1). Thus, in the pixel to which an electric field is applied, the light intensity determined by the product (Δn · d) of the refractive index anisotropy (Δn) of the liquid crystal and the thickness (d) of the liquid crystal layer is compared with the initial alignment state of the liquid crystal. Transmission characteristics change. In the VA liquid crystal display element, a desired display is performed by utilizing a property that light transmission characteristics change in a pixel to which an electric field is applied.

  The VA liquid crystal display element has excellent response characteristics, wide viewing angle characteristics, and high viewing angle characteristics compared to a TN (Twisted Nematic) type liquid crystal display element and a STN (Super Twisted Nematic) type liquid crystal display element. Contrast display can be realized (see, for example, Patent Document 2). VA type liquid crystal display elements are actively used for, for example, display devices for liquid crystal televisions and portable information devices, and so-called in-vehicle devices such as instrument panels for vehicles such as automobiles.

  In such a VA liquid crystal display element, as described above, the liquid crystal in the liquid crystal layer when no voltage is applied is vertically or substantially perpendicular to the substrate surface. However, it may not be desirable for the liquid crystal to be perfectly vertically aligned. When the orientation of the liquid crystal when no voltage is applied is completely perpendicular to the substrate, the direction in which the liquid crystal tilts cannot be defined when a voltage in a direction completely perpendicular to the substrate surface is applied. As a result, the orientation of the liquid crystal during voltage application is not uniform and the display quality is degraded. Therefore, in the VA liquid crystal display element, the direction in which the vertically aligned liquid crystal is tilted by applying a voltage by giving a pretilt angle to the liquid crystal in the liquid crystal layer or devising the electrode shape by some method is used. It is necessary to specify.

As a method for forming the pretilt angle of the liquid crystal in the liquid crystal layer, there is an oblique deposition method in which silicon oxide (SiO ₂ ) is obliquely deposited with respect to the substrate. Also known is a rib method in which a rib structure (protrusion structure) is provided on the electrode surface. Further, as a method for defining the direction in which the vertically aligned liquid crystal is tilted by voltage application, a method of providing a slit in an electrode (for example, see Patent Document 3) has been studied.

  Further, as a method for forming the pretilt angle of the liquid crystal, there is a method in which a liquid crystal alignment film is provided on the surface of each substrate sandwiching the liquid crystal layer and a liquid crystal alignment film is subjected to alignment treatment. For example, a pre-tilt angle can be given to the vertically aligned liquid crystal by using a vertical alignment liquid crystal alignment film and performing a rubbing treatment. In the liquid crystal of the liquid crystal layer, it is possible to realize a substantially vertical alignment in which a uniform pretilt angle is formed in a predetermined direction.

JP 2003-207782 A JP 2006-11362 A JP 2010-256738 A

  However, as a method for forming uniform substantially vertical alignment in a VA liquid crystal display element, the above-described oblique deposition method requires a large-scale apparatus and is difficult to apply to a large substrate, thereby improving productivity. There was no problem.

  Further, the rib method (installation of the protrusion structure) requires a rib structure forming step, which increases the number of steps in manufacturing a liquid crystal display element, and increases production costs.

  Therefore, in the VA liquid crystal display element, rubbing treatment has been frequently used as a simpler method for forming uniform, substantially vertical alignment.

  However, the rubbing treatment is a method of rubbing the surface of the alignment film made of a resin such as polyimide with a cloth, and it is difficult to perform the alignment treatment with high uniformity. Easy to get scratched. As a result, streaky display unevenness may appear in the display of the liquid crystal display element, and there is a tendency that display quality and yield are likely to decrease.

  In addition, the VA type liquid crystal display element generally has a high insulation property of the alignment film, and is easily charged by the influence of an external electrostatic field to cause an abnormal display. Further, the abnormal display state can be maintained for a long time. Have. For example, when such a VA-type liquid crystal display element is mounted and assembled in an image display system such as a TV, it is abnormally lit due to static electricity during assembly, and a long period of time until the abnormally lit state is resolved. Problems such as inability to move to the process occurred. As a method of solving such a problem of electrostatic charging, a method of providing a ground electrode as a transparent electrode for eliminating an electrostatic field is known outside a liquid crystal panel constituting a liquid crystal display element. However, there is a problem of increasing the cost of manufacturing the product.

  Therefore, in a liquid crystal display element such as a TN type or STN type, a method is known in which ionic impurities are added to the liquid crystal, the conductivity of the liquid crystal layer is increased, the panel specific resistance is decreased, and charging is eliminated. Yes. This method of reducing the panel specific resistance is simple, does not increase the manufacturing cost of the product, and is an effective method for eliminating the charge of the liquid crystal display element.

  However, as a result of studies by the inventors, it has been found that in VA liquid crystal display elements subjected to rubbing treatment, the addition of ionic impurities to the liquid crystal layer promotes the above-described unique display unevenness. Yes. Therefore, in the VA liquid crystal display element, it is difficult to adopt the above-described simple charge elimination method that is effective in the STN liquid crystal display element.

  For this reason, there is a need for a technology that can easily define the direction in which the vertically aligned liquid crystal tilts when a voltage is not applied in a VA liquid crystal display element. In addition, it is preferable that the technique can be used in combination with a method for eliminating the charge of the liquid crystal display element.

  The present invention has been made in view of these points. That is, an object of the present invention is to provide a liquid crystal display element that can easily define the direction in which the vertically aligned liquid crystal is tilted and aligned by applying a voltage.

  Other objects and advantages of the present invention will become apparent from the following description.

One embodiment of the present invention includes a first substrate over which a first electrode is disposed, a second substrate over which a second electrode facing the first electrode is disposed, a first substrate, and a second substrate A liquid crystal display element having a liquid crystal layer disposed between the substrate and a liquid crystal layer in which the orientation of liquid crystal when no voltage is applied is vertical,
The first electrode has a plurality of first openings regularly arranged in the first direction,
The second electrode has a plurality of second openings regularly arranged in the first direction,
The first opening of the first electrode has a trapezoidal shape, and two parallel sides are parallel to the first direction, and the sides facing each other in the first direction are mutually opposite. Parallel,
The second opening of the second electrode has a trapezoidal shape, and the two parallel sides are parallel to the first direction, and the sides facing each other in the first direction are mutually opposite. Parallel,
The first opening and the second opening are arranged so that the first opening and the second opening are shifted in a second direction perpendicular to the first direction in a plan view and are partially overlapped with each other. The present invention relates to a liquid crystal display element.

  In one embodiment of the present invention, a first polarizing plate disposed on a surface opposite to a first electrode disposition surface of the first substrate and a second electrode disposing surface opposite to the second electrode disposition surface The first polarizing plate and the second polarizing plate are arranged so that their absorption axes are orthogonal to each other, and the first direction and 45 degrees are respectively It is preferable that they are arranged at an angle.

  In one embodiment of the present invention, the first opening and the second opening preferably have a width in the first direction of 8 μm to 30 μm.

  In one embodiment of the present invention, the distance between adjacent ones of the plurality of first openings and the distance between adjacent ones of the plurality of second electrodes are preferably 20 μm to 120 μm.

  In one embodiment of the present invention, each of the first opening and the second opening preferably has an internal angle in the range of 40 degrees to 140 degrees.

In one embodiment of the present invention, the specific resistance of the liquid crystal is preferably in the range of 1 × 10 ¹⁰ Ωm to 2 × 10 ¹¹ Ωcm.

  In one embodiment of the present invention, it is preferable that at least one of the first substrate and the second substrate be subjected to an alignment treatment so that the liquid crystal is vertically aligned with a predetermined pretilt angle.

  According to one embodiment of the present invention, there is provided a liquid crystal display element capable of easily specifying a direction in which a vertically aligned liquid crystal is tilted and aligned by applying a voltage.

It is a top view which shows typically a part of electrode structure of the liquid crystal display element of embodiment of this invention. It is a figure which shows typically the cross-sectional structure along the A-A 'line | wire of FIG. It is a top view which shows another example of the opening part structure of the electrode of a VA type liquid crystal display element. It is a top view which shows another example of the opening part structure of the liquid crystal display element of embodiment of this invention.

  In the VA liquid crystal display element, there is a demand for a technology that can easily define the direction in which the vertically aligned liquid crystal is tilted when no voltage is applied. For this reason, the oblique vapor deposition method and the rib method have been studied, but there is a concern that the productivity will decrease. Therefore, a simpler rubbing method is used. However, this method has a problem of deterioration in display quality and yield.

  Therefore, in order to solve the problems of deterioration in display quality and yield due to rubbing, as described above, a method of providing a slit in the electrode sandwiching the liquid crystal layer has been studied.

  For example, as described in Patent Document 3, a first electrode and a second electrode are provided so as to sandwich a liquid crystal layer in which liquid crystals are vertically aligned, and each of the first electrodes has a plurality of rectangular shapes. A first opening is provided, and the second electrode is also provided with a plurality of second openings each provided in a rectangular shape. The plurality of first openings have at least a part of each first side overlapped with one or more of the plurality of second openings in a plan view and a second side facing the first side. It arrange | positions so that it may oppose with a 2nd electrode, without overlapping any of several 2nd opening part in planar view. By providing the rectangular first openings and second openings as described above as the slits of the electrodes, the vertically aligned liquid crystal can be applied in a desired direction by applying a voltage without performing an alignment treatment such as rubbing. It is possible to realize monodomain alignment that is inclined in the direction.

  However, with these conventional technologies, mono-domain alignment is achieved, but liquid crystal alignment controlled to a high level is achieved, such as uniform tilt alignment of the liquid crystal within the display surface when a voltage is applied. Therefore, it is impossible to realize a high-quality VA liquid crystal display element.

  That is, the slit is an opening provided in the electrodes, and the entire structure (shape) functions to form an oblique electric field between the electrodes. On the other hand, monodomain alignment is intended to realize tilt alignment in one direction of liquid crystal using an oblique electric field by the opening. Therefore, for example, in the case of the technique described in Patent Document 3 described above, an oblique electric field is not generated only on the first side of the first opening of the first electrode, but the first side is continuous with the first side. Also in the third side and the fourth side formed perpendicular to each other, an oblique electric field having a property different from the oblique electric field formed by the first side is generated.

  In the technique described in Patent Document 3, the first opening is shaped as a rectangle having the first side as the long side, the third side and the fourth side that are continuous with the first side are set as the short side, The influence of the oblique electric field generated by the side is made more dominant. As a result, the above-described monodomain orientation is realized. However, the influence of the third side and the fourth side that are continuous with the first side is not eliminated, and the display quality of the liquid crystal display element is affected as a disorder of the liquid crystal alignment.

  For example, in the technique described in Patent Document 3 described above, between the first openings adjacent to each other in the longitudinal direction of the rectangular first opening and between the second openings adjacent to each other in the longitudinal direction of the rectangular second opening. In this region, when a voltage is applied, a liquid crystal alignment state different from other normal regions is formed. In the case of the technique described in Patent Document 3, the structure of the first opening and the second opening is different from the other regions in the alignment state of the liquid crystal generated in the region between the first opening and the second opening. It has not been taken into account.

  For this reason, in the technique described in Patent Document 3, the alignment state of the liquid crystal different from other regions generated between the first and second openings is a so-called liquid crystal alignment disorder. The technique described in Patent Document 3 cannot control the alignment disorder and is easily detected as light leakage. As a result, in the liquid crystal display element described in Patent Document 3, such alignment disorder tends to be conspicuous as a decrease in contrast or display unevenness, and tends to reduce display quality.

  From the above, in a VA liquid crystal display element, when a slit is provided in an electrode and the direction in which the vertically aligned liquid crystal tilts when no voltage is applied is determined, the shape of the slit and its arrangement structure are important. . In particular, the shape of the slit needs to be fully considered. In order to realize a better display quality in the liquid crystal display element, it is essential to sufficiently study the shape of the slit and the arrangement structure thereof.

That is, in the VA liquid crystal display element, there is a demand for a slit technology that defines the direction in which the vertically aligned liquid crystal tilts when no voltage is applied, and realizes excellent display quality.
The present inventor has intensively studied in order to meet such demands and has arrived at the present invention. Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a plan view schematically showing a part of an electrode structure of a liquid crystal display element according to an embodiment of the present invention.

The liquid crystal display element 1 according to the embodiment of the present invention shown in FIG. 1 includes a first substrate (not shown in FIG. 1) on which a first electrode 2 is disposed, and a second electrode facing the first electrode 2. A second substrate on which the electrode 4 is arranged (not shown in FIG. 1), and a liquid crystal that is arranged between the first substrate and the second substrate when no voltage is applied (not shown in FIG. 1) This is a VA liquid crystal display element having a liquid crystal layer (not shown in FIG. 1) whose vertical orientation is vertical. A first polarizing plate (not shown) is disposed on the surface of the first substrate opposite to the surface on which the first electrode 2 is disposed, and the surface opposite to the surface on which the second electrode 4 is disposed on the second substrate. A second polarizing plate (not shown) is disposed on the surface.
In FIG. 1, the first electrode 2 and the second electrode 4 that overlap with a liquid crystal layer (not shown) interposed therebetween are shown in plan view.

  The 1st board | substrate with which the 1st electrode 2 is arrange | positioned is arrange | positioned at the front side which becomes a viewer side, for example, and the 2nd board | substrate with which the 2nd electrode 4 is arrange | positioned is a back surface which becomes an anti-viewer side. Placed on the side.

  The first electrode 2 is, for example, a plurality of first openings that are regularly arranged at a predetermined distance in a desired first direction (horizontal direction in FIG. 1) that is a horizontal direction. 8 has. The second electrode 4 also has a plurality of second openings 9 regularly arranged at a predetermined distance in the first direction.

Then, with the first direction as a reference, the first polarizing plate and the second polarizing plate described above have an absorption axis orthogonal to each other and the respective absorption axes are 45 degrees with respect to the first direction. Arranged at an angle.
In the case of providing a polarizing plate in the liquid crystal display element, for example, a method of setting the absorption axis or the polarizing axis of the polarizing plate is performed with reference to the long side direction of the rectangular liquid crystal display element. In the liquid crystal display element 1 of the present embodiment, the first direction in which the first opening 8 and the second opening 9 are arranged can be set with the long side direction of the liquid crystal display element 1 as a reference. Therefore, the setting of the polarizing plate can be based on the long side direction of the liquid crystal display element 1 as a result by using the first direction as a reference.

  The first opening 8 of the first electrode 2 and the second opening 9 of the second electrode 4 have the same shape in which at least one pair of opposite sides (opposite sides) are parallel to each other. It is preferable. And as for the 1st opening part 8 and the 2nd opening part 9, it is preferable that the two parallel sides are respectively parallel to the 1st direction which is a horizontal direction, for example. Since the first opening 8 of the first electrode 2 and the second opening 9 of the second electrode 4 have the same shape as described above, in the liquid crystal display element 1, as described later, The same alignment state of the monodomain liquid crystal as when the rubbing process is performed in the direction perpendicular to the first direction is realized.

The first opening 8 and the second opening 9 preferably have a trapezoidal shape in which at least one pair of opposite sides is parallel to each other, and each of the two parallel sides is, for example, a horizontal direction. It is preferable to be parallel to the direction of 1.
In the present invention, a trapezoidal shape is given as a preferred example of a shape in which at least one pair of opposite sides are parallel to each other. However, the trapezoidal shape of the present invention includes the first opening 8 shown in FIG. The shape illustrated in the second opening 9, that is, a parallelogram shape having an upper base and a lower base having equal lengths is also included.

  Furthermore, in the plurality of first openings 8 of the first electrode 2, it is preferable that the sides facing each other adjacent to each other in the first direction are parallel to each other. Similarly, also in the second electrode 4, it is preferable that the sides facing each other between the second openings 9 adjacent in the first direction are parallel to each other.

  As shown in FIG. 1, the first opening 8 and the second opening 9 are shifted in a second direction perpendicular to the first direction in a plan view, and a part of each other is formed. It is preferable to arrange so that it may overlap.

  In the liquid crystal display element 1 shown in FIG. 1, the second opening 9 is arranged to be shifted downward with respect to the first opening 8 in a plan view in parallel with the second direction. In the liquid crystal display element 1 shown in FIG. 1, the first opening 8 of the first electrode 2 and the second opening 9 of the second electrode 4 have the same shape, and the second opening described above. If there is no deviation in the direction parallel to the direction, the superposition is made to coincide with each other in plan view.

  FIG. 2 is a diagram schematically showing a cross-sectional structure along the line A-A ′ of FIG. 1.

  As described above, the liquid crystal display element 1 includes the first substrate 3 on which the first electrode 2 is disposed, and the second substrate 5 on which the second electrode 4 facing the first electrode 2 is disposed. The liquid crystal layer 7 is arranged between the first substrate 3 and the second substrate 5 so that the alignment of the liquid crystal 6 when no voltage is applied is a vertical alignment.

  As shown in FIG. 2, the first opening 8 and the second opening 9 of the liquid crystal display element 1 are shifted in a second direction (left-right direction in FIG. 2) perpendicular to the first direction, It arrange | positions so that a part of each other may overlap.

As a result, application of a voltage between the first electrode 2 and the second electrode 4 forms an oblique electric field 11 between the electrode edges. In the liquid crystal display element 1, the orientation of the liquid crystal 6 in the liquid crystal layer 7 sandwiched between the first electrode 2 and the second electrode 4 changes so as to correspond to the formation of the oblique electric field 11. That is, the liquid crystal 6 is tilted and aligned in a uniform direction. In the liquid crystal display element 1, the alignment state of the monodomain liquid crystal 6 is the same as when the rubbing process is performed in a direction parallel to the second direction. Is realized.
Note that an arrow 12 in FIG. 2 is an arrow schematically showing the viewing angle direction of the liquid crystal display element 1.

  At this time, the first opening 8 of the first electrode 2 and the second opening 9 of the second electrode 4 have a trapezoidal shape in which at least one pair of opposite sides are parallel to each other, as described above. Preferably there is. Furthermore, it is preferable that the first opening 8 and the second opening 9 are parallel to each other in the sides facing each other adjacent to each other in the first direction.

  More specifically, a plurality of first openings 8 are arranged at a predetermined distance in the first direction. The plurality of first openings 8 are regions between two opposing sides of adjacent ones, that is, regions surrounded by four ends of the two opposing sides (hereinafter referred to as openings for convenience). It is preferable that the intermediate region has a parallelogram shape. Similarly, a plurality of second openings 9 are arranged at a predetermined distance in the first direction. The plurality of second openings 9 are parallel to each other between the adjacent two sides of the adjacent ones, that is, the region surrounded by the four ends of the two opposite sides (inter-opening region). It preferably has a quadrilateral shape.

  In that case, for example, as shown in FIG. 1, it is preferable that the first opening 8 and the region between the openings have a parallelogram shape, for example. Similarly, in the second opening 9, it is preferable that the second opening 9 and the region between the openings have a parallelogram shape, for example.

  In the following, in a plan view, a region sandwiched between the two first openings 8 and the two second openings 9, that is, a region between the openings in the first opening 8 and the second opening. A region between the two first openings 8 and the two second openings 9 formed by overlapping a part of the region between the openings in 9 is referred to as a connection region.

  By making the first opening 8 and the second opening 9 in the shape and arrangement structure as described above, the alignment state of the liquid crystal in the connection region can be controlled to be preferable, and light leakage is reduced. The contrast can be improved, display unevenness can be made inconspicuous, and the display quality can be improved.

  FIG. 3 is a plan view showing another example of the electrode opening structure of the VA liquid crystal display element.

  FIG. 3 shows an example in which the first opening 108 and the second opening 109 are provided in a rectangular shape (rectangular shape), and the arrangement structure and the like are the same as those in the example of FIG. Therefore, the same components as those in the example of FIG. The example illustrated in FIG. 3 corresponds to, for example, the conventional technique described in Patent Document 3 described above.

  In the example illustrated in FIG. 3, the first direction in which the first opening 108 and the second opening 109 are arranged is parallel to the longitudinal direction thereof. In that case, in the connection region sandwiched between the first opening 108 and the second opening 109 adjacent to each other in the first direction, the liquid crystal operation during voltage application is performed in other regions (hereinafter referred to as the other regions). A region different from the normal region for convenience (hereinafter referred to as an abnormal region for convenience) appears.

  That is, in the normal region, the second opening is shifted in the second direction with respect to the first opening, thereby realizing a change in the alignment of the liquid crystal parallel to the second direction when a voltage is applied. On the other hand, in the abnormal region appearing in the connection region sandwiched between the first opening 108 and the second opening 109, the direction of the change in the alignment of the liquid crystal is the change in the alignment of the liquid crystal when a voltage is applied in the normal region. And the angle of 180 degrees are different. That is, in the abnormal region, when compared with the normal region, an alignment change occurs in which the liquid crystal is inclined in the opposite direction when a voltage is applied.

  As a result, the orientation change direction of the liquid crystal in the normal region and the orientation change direction of the liquid crystal in the abnormal region are close to 45 degrees with respect to the absorption axis direction of the polarizing plate, respectively. Therefore, in the connection region sandwiched between the first opening and the second opening, light leakage is likely to occur due to the occurrence of an abnormal region, which tends to be conspicuous as a decrease in contrast or display unevenness, and tends to reduce display quality. It was.

  On the other hand, in the liquid crystal display element 1 of this embodiment shown in FIG. 1, the 1st opening part 8 and the 2nd opening part 9 are made into trapezoid shape, and between each adjacent in a 1st direction in each. Opposing sides can be parallel to each other. As a result, the inter-opening region in the first opening 8 and the inter-opening region in the second opening 9 can each be a parallelogram. In that case, in the connection region sandwiched between the first opening 8 and the second opening 9, the direction of the change in the orientation of the liquid crystal can be shifted from the direction of 45 degrees with respect to the absorption axis direction of the polarizing plate. Therefore, in the liquid crystal display element 1 of the present embodiment shown in FIG. 1, light leakage in the connection region can be reduced, contrast can be improved, and display unevenness can be made inconspicuous. Therefore, the liquid crystal display element 1 of this embodiment can improve display quality.

  Here, in the liquid crystal display element 1 shown in FIG. 1, the second opening 9 is shifted from the first opening 8 in a downward direction parallel to the second direction in plan view. Has been. However, the liquid crystal display element of this embodiment is not limited to the arrangement structure of the first opening 8 and the second opening 9 as shown in FIG. The liquid crystal display element of the present embodiment may have a structure in which the second opening is arranged to be shifted upward in parallel with the second direction in plan view with respect to the first opening. Is possible. Even with such a structure, the liquid crystal display element of the present embodiment realizes the alignment state of the monodomain liquid crystal. Further, light leakage in the connection region sandwiched between the first opening and the second opening is reduced, contrast is improved, display unevenness is less noticeable, and display quality is improved as described above. Can be realized.

  In the liquid crystal display element of the present embodiment, as described above, the first opening of the first electrode and the second opening of the second electrode each have at least one pair of opposing sides ( The opposite sides are preferably parallel to each other, and the inter-opening region in the first electrode and the inter-opening region in the second electrode are preferably parallelograms. And if the liquid crystal display element of this embodiment is such a structure, the 1st opening part of a 1st electrode and the 2nd opening part of a 2nd electrode will respectively have shapes other than what was mentioned above. It can be.

  FIG. 4 is a plan view showing another example of the opening structure of the liquid crystal display element according to the embodiment of the present invention.

  FIG. 4 shows the structure of the first opening 8a of the first electrode 2a of the liquid crystal display element (not shown) of the present embodiment. At this time, the structure of the second opening (not shown) of the second electrode (not shown) can be the same.

  In the first opening 8a of the first electrode 2a shown in FIG. 4, each has the same isosceles trapezoid shape. Then, for example, in the first direction which is the horizontal direction, the one whose upper base is longer than the lower base and one whose lower base is longer than the upper base are arranged alternately. By having such a shape and arrangement structure, in the first opening 8a of the first electrode 2a, opposing sides (opposite sides) are parallel to each other, and the regions between the openings are each in a parallelogram shape. A structure can be realized.

  Note that the first opening of the first electrode of the liquid crystal display element of the present embodiment is not limited to the isosceles trapezoidal shape as shown in FIG. 3, and the region between the openings may be a parallelogram shape. For example, it may be a trapezoid that is not an equal leg.

  Furthermore, in the liquid crystal display element of the present embodiment, in the first electrode, if the region between the openings is a parallelogram shape, the openings having different shapes are arranged in combination along the first direction. Is also possible. In that case, also in the second electrode, similarly to the first electrode, it is also possible to arrange openings having different shapes in combination along the first direction.

  Next, the structure of the first opening and the second opening in the present embodiment will be described in more detail with reference to FIG.

  The width in the direction perpendicular to the longitudinal direction of the first opening 8 and the second opening 9 (the width in the first direction) is preferably set in the range of 8 μm to 30 μm. When the thickness is less than 8 μm, the influence of the oblique electric field generated by the first opening 8 and the second opening 9 is reduced, and the alignment regulating force of the liquid crystal is lowered, so that a uniform alignment change cannot be obtained. Further, the manufacturing margin at the time of manufacturing the liquid crystal display element 1 becomes strict. On the other hand, when the thickness is larger than 30 μm, the non-lighted area increases due to the first opening 8 and the second opening 9, and the transmittance of the liquid crystal display element 1 is lowered.

  When the lengths of the first opening 8 and the second opening 9 are defined as [(length) = (upper base + lower base) / 2], the length is in the range of 40 μm to 300 μm. It is preferable that it is set. When the thickness is less than 40 μm, the alignment regulating force of the liquid crystal is lowered and a uniform alignment change cannot be obtained. On the other hand, if it is larger than 300 μm, there is no connection area depending on the display pattern (lighting pattern), and a portion that does not light is likely to be generated.

  The distance between the openings adjacent to each other in the longitudinal direction (first direction) of the first opening 8 and the second opening 9 is preferably arranged in the range of 5 μm to 30 μm. This is because if the thickness is less than 5 μm, disconnection is likely to occur. On the other hand, if it is larger than 30 μm, the liquid crystal alignment state in the connection region is deteriorated and light leakage is likely to occur.

  As shown in FIG. 1, the liquid crystal display element 1 of the present embodiment has a plurality of first openings 8 regularly arranged in the first direction. A plurality of rows can be regularly arranged in a second direction orthogonal to the first direction. Similarly, the second openings 9 can also have a plurality of rows of the second openings 9 in the first direction regularly arranged in the second direction.

  In that case, in the 1st opening part 8 and the 2nd opening part 9, it is preferable that the distance between the opening parts adjacent to a 2nd direction is arrange | positioned in the range of 20 micrometers-120 micrometers. This is because, when the thickness is less than 20 μm, the portion that is not lit up due to the opening increases, and the transmittance decreases. On the other hand, if it is larger than 120 μm, the influence of the oblique electric field generated by the first opening 8 and the second opening 9 does not reach the vicinity of the center between the openings in the second direction. This is because the transmittance in the vicinity is lowered. Also, the response speed tends to be slow. However, at least one of the first substrate 3 and the second substrate 5 sandwiching the liquid crystal layer 7 shown in FIG. 2 is subjected to alignment treatment, and the liquid crystal 6 is configured to have a predetermined pretilt angle and to be vertically aligned. If it is, it may be larger than 120 μm.

  The shapes of the first opening 8 and the second opening 9 are preferably trapezoidal, but the angles of the four inner angles of the trapezoid are preferably in the range of 40 degrees to 140 degrees. The first opening 8 and the second opening 9 are preferably trapezoidal, and are excluded when all four interior angles are 90 degrees. The shape of the first opening 8 and the second opening 9 is a trapezoidal shape, and each parallel two sides are parallel to the first direction, and the openings adjacent to each other in the first direction are opposed to each other. By making the sides to be parallel to each other, the regions between the openings of the first opening 8 and the second opening 9 have a parallelogram shape. By doing in this way, the liquid crystal orientation state in the connection area | region of the 1st opening part 8 and the 2nd opening part 9 can be shifted from the 45 degree direction with respect to the absorption-axis direction of a polarizing plate. As a result, the liquid crystal display element 1 reduces light leakage in the connection region, improves the contrast, makes display unevenness less noticeable, and improves the display quality.

  The liquid crystal display element 1 of the present embodiment has the above-described electrode structure and excellent display quality, but further has a specific resistance (also referred to as a panel specific resistance) so that electrostatic charge can be easily eliminated. It is preferable to set the desired range.

The panel specific resistance of the liquid crystal display element 1 is preferably in the range of 1 × 10 ¹⁰ Ωcm to 2 × 10 ¹¹ Ωcm. By setting the panel specific resistance within such a range, it becomes easy to eliminate the electrostatic charge. Even if the panel specific resistance is controlled by a method of adding an additive to the liquid crystal 6 as will be described later, this does not have an undesirable effect on the liquid crystal characteristics. The panel specific resistance is more preferably in the range of 1 × 10 ¹⁰ Ωcm to 1 × 10 ¹¹ Ωcm. By setting the panel specific resistance within such a range, it becomes easier to eliminate the electrostatic charge.

  The panel specific resistance defined here is a liquid crystal layer evaluated using the liquid crystal display element after being manufactured and sandwiched between electrodes disposed on each of a pair of opposing substrates. Specific resistance. For example, in contrast to the so-called bulk specific resistance of the liquid crystal before being applied to the liquid crystal display element, the panel specific resistance referred to here is a characteristic after being applied to the liquid crystal display element. It is called “Panel resistivity”.

  The method for adjusting the panel specific resistance can be realized by introducing ionic impurities into the liquid crystal 6 of the liquid crystal layer 7 constituting the liquid crystal display element 1. For effective introduction of ionic impurities into the liquid crystal 6 and adjustment of specific resistance, in addition to the method of directly introducing ionic impurities, phenothiazine and Tris (2- ( It can also be realized by adding, as an additive, a compound that effectively introduces ionic impurities into the liquid crystal such as 2-methoxyethyl) ethyl) amine (hereinafter abbreviated as TDA).

  In the liquid crystal display element 1 of the present embodiment, liquid crystal whose conductivity is improved by adding ionic impurities to reduce charge is used, and the panel specific resistance is lowered. In addition, in the liquid crystal display element of the present embodiment, the first opening 8 and the second opening 9 having the above-described structure are arranged in the first electrode 2 and the second electrode 4, respectively, and the liquid crystal display element 1 is configured to suppress the flow of the liquid crystal 6 generated in the inside. By providing such a structure, the liquid crystal display element 1 of the present embodiment can realize reduction of charging and display unevenness.

  Moreover, the liquid crystal display element of embodiment of this invention can have a liquid crystal aligning film for controlling the alignment of a liquid crystal uniformly. The liquid crystal alignment film is formed between the first electrode of the first substrate that sandwiches the liquid crystal layer and the liquid crystal layer, and the second electrode of the second substrate that faces the first substrate across the liquid crystal layer. It is preferable to arrange at least one between the liquid crystal layer and the liquid crystal layer.

  Furthermore, the liquid crystal display element according to the embodiment of the present invention includes the first substrate and the second substrate sandwiching the liquid crystal layer so that the liquid crystal has a predetermined pretilt angle and is vertically aligned when no voltage is applied. It is preferable to perform orientation treatment on at least one of them.

  By using the alignment treatment in combination, the alignment regulating force of the liquid crystal is strengthened. For example, in the electrode structure of the liquid crystal display element 1 shown in FIG. 1, the second direction of the first opening 8 and the second opening 9. It is because the arrangement | positioning space | interval can be expanded and the fall of the transmittance | permeability can be suppressed.

  In that case, the pretilt angle of the liquid crystal is preferably set in the range of 89.6 degrees to 90.0 degrees. In particular, the pretilt angle is preferably set in the range of 89.8 degrees to 90.0 degrees. This is to suppress an increase in transmittance during black display due to the formation of the pretilt angle.

The alignment process can be performed by performing a rubbing process on the liquid crystal alignment film disposed on the first substrate and / or the second substrate.
The method of performing the rubbing process tends to cause a decrease in display quality or a decrease in yield due to rubbing such as streak display unevenness. However, by setting the pretilt angle high, or by performing an alignment process on one of the first substrate and the second substrate, the display quality is lowered or the yield is lowered due to rubbing of display unevenness such as streaks. Can be made difficult to happen.

  Hereinafter, embodiments of the present invention will be described more specifically based on examples. However, the present invention is not limited to these examples.

Example 1.
A liquid crystal display device according to the first embodiment of the present invention was manufactured. The liquid crystal display element of the first embodiment is a VA type liquid crystal display element, and has the same electrode structure as that shown in FIGS.

  First, in order to manufacture the liquid crystal display element of the first embodiment of the present invention, a pair of glass substrates with an ITO film was prepared. One substrate was a first substrate having a segment electrode as a first electrode, and the other was a second substrate having a common electrode as a second electrode.

  In the liquid crystal display device of the first embodiment of the present invention, the segment electrode and the common electrode are patterned, and a plurality of substantially the same opening pattern is formed in the same manner as shown in FIG. 1 and FIG. Arranged.

Specifically, the opening of the segment electrode and the common electrode has a width of 16 μm in the direction orthogonal to the longitudinal direction (corresponding to the first direction in FIG. 1) (corresponding to the second direction in FIG. 1), and the opening , That is, the length according to the above definition ((upper base + lower base) / 2) is 100 μm, and the angles of the four inner angles are 60 degrees, 120 degrees, 60 degrees and 120 degrees, respectively. It was formed to have. The distance between the openings adjacent in the longitudinal direction of the openings was 10 μm, and the distance between the openings adjacent in the width direction of the openings was 80 μm.
Then, in plan view, the opening of the common electrode on the anti-viewer side is shifted by 8 μm upward (12 o'clock direction) in parallel with the second direction with respect to the opening of the segment electrode on the viewer side. It was made to become the arrangement.

  In the liquid crystal display element according to the first embodiment of the present invention, the long side direction of the liquid crystal panel, which will be described later, and the longitudinal direction of the openings of the segment electrode and the common electrode are made parallel. Yes.

  Next, a vertical alignment liquid crystal alignment film was formed on the segment electrode formation surface of the first substrate and the common electrode formation surface of the second substrate, and a liquid crystal was sandwiched to manufacture a VA liquid crystal panel. A liquid crystal having a dielectric anisotropy (Δε) of −4.4 was used. The retardation (Δn · d) of the liquid crystal panel was set to 400 nm.

  Next, using the manufactured liquid crystal panel, a VA liquid crystal display element was manufactured by being sandwiched between a pair of polarizing plates including a first polarizing plate on the viewer side and a second polarizing plate on the non-viewer side. VHC-128UL2SZ-K1 made by Polatechno Co., Ltd. is used as the first polarizing plate, and 000R220N-VH39L2S (Re ≦ 7 nm, Rth = 220 nm, made by Polatechno Co., Ltd. is attached as the second polarizing plate. Polarizing plate) was used.

  At this time, assuming that the counterclockwise angle from the reference axis when viewed from the viewing side to the absorption axis of the F polarizing plate is θ1 with the long side direction of the liquid crystal panel as the reference axis, θ1 = 45 degrees. When the counterclockwise angle to the absorption axis of the R polarizing plate is θ2, θ2 = 135 degrees. Although the absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate are orthogonal to each other, the respective polarization axes may be orthogonal to each other.

  When the liquid crystal display element manufactured as described above was used and driven at a duty ratio of 1/4, good visibility was obtained. That is, a good black display was obtained when no voltage was applied or when the display was turned off (OFF), and a bright white display was obtained when the voltage was turned on (ON). In particular, bright and good visibility was obtained on the lower side (6 o'clock direction) in a direction orthogonal to the long side direction of the liquid crystal panel, and display unevenness such as streaks was not observed.

Example 2
A liquid crystal display device according to the second embodiment of the present invention was manufactured. The liquid crystal display element of the second embodiment is a VA type liquid crystal display element, and a similar trapezoidal opening is formed in each of the segment electrode and the common electrode that sandwich the liquid crystal layer, as shown in FIG. Several are arranged.

  First, in order to manufacture the liquid crystal display element of the second embodiment of the present invention, a pair of glass substrates with an ITO film was prepared. One substrate was a first substrate having a segment electrode as a first electrode, and the other was a second substrate having a common electrode as a second electrode.

  In the liquid crystal display device according to the second embodiment of the present invention, the segment electrodes and the common electrodes are patterned, and a plurality of substantially the same opening patterns are formed on each of them, and are arranged in the same manner as shown in FIG. .

Specifically, the opening of the segment electrode and the common electrode has a width of 16 μm in the direction orthogonal to the longitudinal direction (corresponding to the first direction in FIG. 1) (corresponding to the second direction in FIG. 1), and the opening A trapezoid whose length ((upper base + lower base) / 2) is 100 μm and the angles of the four interior angles are 45 degrees, 135 degrees, 60 degrees and 120 degrees, respectively. Formed to have. The distance between the openings adjacent in the longitudinal direction of the openings was 10 μm, and the distance between the openings adjacent in the width direction of the openings was 80 μm.
Then, in plan view, the opening of the common electrode on the anti-viewer side is shifted by 8 μm upward (12 o'clock direction) in parallel with the second direction with respect to the opening of the segment electrode on the viewer side. It was made to become the arrangement.

  In the liquid crystal display element according to the first embodiment of the present invention, the long side direction of the liquid crystal panel, which will be described later, and the longitudinal direction of the openings of the segment electrode and the common electrode are made parallel. Yes.

  Next, a vertical alignment liquid crystal alignment film was formed on the segment electrode formation surface of the first substrate and the common electrode formation surface of the second substrate, and a liquid crystal was sandwiched to manufacture a VA liquid crystal panel. A liquid crystal having a dielectric anisotropy (Δε) of −4.4 was used. The retardation (Δn · d) of the liquid crystal panel was set to 400 nm.

  Next, using the manufactured liquid crystal panel, a VA liquid crystal display element was manufactured by being sandwiched between a pair of polarizing plates including a first polarizing plate on the viewer side and a second polarizing plate on the non-viewer side. VHC-128UL2SZ-K1 made by Polatechno Co., Ltd. is used as the first polarizing plate, and 000R220N-VH39L2S (Re ≦ 7 nm, Rth = 220 nm, made by Polatechno Co., Ltd. is attached as the second polarizing plate. Polarizing plate) was used.

  At this time, assuming that the counterclockwise angle from the reference axis when viewed from the viewing side to the absorption axis of the F polarizing plate is θ1 with the long side direction of the liquid crystal panel as the reference axis, θ1 = 45 degrees. When the counterclockwise angle to the absorption axis of the R polarizing plate is θ2, θ2 = 135 degrees. Although the absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate are orthogonal to each other, the respective polarization axes may be orthogonal to each other.

  When the liquid crystal display element manufactured as described above was used and driven at a duty ratio of 1/4, good visibility was obtained. That is, a good black display was obtained when no voltage was applied or when the display was turned off (OFF), and a bright white display was obtained when the voltage was turned on (ON). In particular, bright and good visibility was obtained on the lower side (6 o'clock direction) in a direction orthogonal to the long side direction of the liquid crystal panel, and display unevenness such as streaks was not observed.

Example 3
A liquid crystal display device according to the third embodiment of the present invention was manufactured. The liquid crystal display element of the third embodiment is a VA type liquid crystal display element, has an opening similar to that of the first embodiment described above, and has an electrode structure similar to that of the first embodiment. The electrode structure is the same as that shown in FIG.

  Then, using the first substrate and the second substrate similar to those in the first embodiment, the VA type liquid crystal panel having the same structure as that in the first embodiment was manufactured by sandwiching the liquid crystal and excluding the liquid crystal described later. .

  As the liquid crystal, a liquid crystal having a dielectric anisotropy (Δε) of −4.4 and 200 ppm added as an additive of TDA capable of reducing the specific resistance was used. The retardation (Δn · d) of the liquid crystal panel was set to 400 nm.

  Next, using the manufactured liquid crystal panel, a VA liquid crystal display element was manufactured by being sandwiched between a pair of polarizing plates including a first polarizing plate on the viewer side and a second polarizing plate on the non-viewer side. VHC-128UL2SZ-K1 made by Polatechno Co., Ltd. is used as the first polarizing plate, and 000R220N-VH39L2S (Re ≦ 7 nm, Rth = 220 nm, made by Polatechno Co., Ltd. is attached as the second polarizing plate. Polarizing plate) was used.

  At this time, assuming that the counterclockwise angle from the reference axis when viewed from the viewing side to the absorption axis of the F polarizing plate is θ1 with the long side direction of the liquid crystal panel as the reference axis, θ1 = 45 degrees. When the counterclockwise angle to the absorption axis of the R polarizing plate is θ2, θ2 = 135 degrees. Although the absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate are orthogonal to each other, the respective polarization axes may be orthogonal to each other.

  When the liquid crystal display element manufactured as described above was used and driven at a duty ratio of 1/4, good visibility was obtained. That is, a good black display was obtained when no voltage was applied or when the display was turned off (OFF), and a bright white display was obtained when the voltage was turned on (ON). In particular, bright and good visibility was obtained on the lower side (6 o'clock direction) in a direction orthogonal to the long side direction of the liquid crystal panel, and display unevenness such as streaks was not observed.

In the liquid crystal display element of this example, the panel specific resistance was 4.4 × 10 ¹⁰ Ωcm. Then, when 10 kV static electricity was applied, it was found that the time until charging was canceled was within 30 seconds, which was a short time.

When the same evaluation was performed using the liquid crystal display element of the first example, the panel specific resistance was 4.3 × 10 ¹¹ Ωm, and when 10 kV of static electricity was applied, until charging was eliminated. The time was 300 seconds or more.

  Furthermore, when the lighting evaluation was performed by changing the frame frequency from 70 Hz to 300 Hz using the liquid crystal display element of this example, a display without display unevenness was obtained at all frame frequencies.

  From the above evaluation results, the liquid crystal display element of the third example achieves both charging and display unevenness by using a liquid crystal that is improved in conductivity by addition of ionic impurities and can reduce charging. It was found that it can be reduced.

Example 4
A liquid crystal display device according to the fourth embodiment of the present invention was manufactured. The liquid crystal display element of the fourth embodiment is a VA type liquid crystal display element, and has the same electrode structure as that shown in FIGS.

  First, in order to manufacture the liquid crystal display element of the fourth embodiment of the present invention, a pair of glass substrates with an ITO film was prepared. One substrate was a first substrate having a segment electrode as a first electrode, and the other was a second substrate having a common electrode as a second electrode.

  In the liquid crystal display device of the first embodiment of the present invention, the segment electrode and the common electrode are patterned, and a plurality of substantially the same opening pattern is formed in the same manner as shown in FIG. 1 and FIG. Arranged.

Specifically, the opening of the segment electrode and the common electrode has a width of 16 μm in the direction orthogonal to the longitudinal direction (corresponding to the first direction in FIG. 1) (corresponding to the second direction in FIG. 1), and the opening , That is, the length according to the above definition ((upper base + lower base) / 2) is 100 μm, and the angles of the four inner angles are 60 degrees, 120 degrees, 60 degrees and 120 degrees, respectively. It was formed to have. The distance between the openings adjacent in the longitudinal direction of the openings was 10 μm, and the distance between the openings adjacent in the width direction of the openings was 100 μm.
Then, in plan view, the opening of the common electrode on the anti-viewer side is shifted by 8 μm upward (12 o'clock direction) in parallel with the second direction with respect to the opening of the segment electrode on the viewer side. It was made to become the arrangement.

  In the liquid crystal display element according to the first embodiment of the present invention, the long side direction of the liquid crystal panel, which will be described later, and the longitudinal direction of the openings of the segment electrode and the common electrode are made parallel. Yes.

  Next, a vertical alignment liquid crystal alignment film was formed on the segment electrode formation surface of the first substrate and the common electrode formation surface of the second substrate. Then, only the liquid crystal alignment film on the second substrate was rubbed as an alignment process. Next, a VA liquid crystal panel was manufactured by sandwiching the liquid crystal using the obtained first substrate and the aligned second substrate. A liquid crystal having a dielectric anisotropy (Δε) of −4.4 was used. The retardation (Δn · d) of the liquid crystal panel was set to 400 nm. The pretilt angle of the liquid crystal in the obtained liquid crystal panel was 89.9 degrees.

  Next, using the manufactured liquid crystal panel, a VA liquid crystal display element was manufactured by being sandwiched between a pair of polarizing plates including a first polarizing plate on the viewer side and a second polarizing plate on the non-viewer side. VHC-128UL2SZ-K1 made by Polatechno Co., Ltd. is used as the first polarizing plate, and 000R220N-VH39L2S (Re ≦ 7 nm, Rth = 220 nm, made by Polatechno Co., Ltd. is attached as the second polarizing plate. Polarizing plate) was used.

  At this time, assuming that the counterclockwise angle from the reference axis when viewed from the viewing side to the absorption axis of the F polarizing plate is θ1 with the long side direction of the liquid crystal panel as the reference axis, θ1 = 45 degrees. When the counterclockwise angle to the absorption axis of the R polarizing plate is θ2, θ2 = 135 degrees. Although the absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate are orthogonal to each other, the respective polarization axes may be orthogonal to each other.

  When the liquid crystal display element manufactured as described above was used and driven at a duty ratio of 1/4, good visibility was obtained. That is, a good black display was obtained when no voltage was applied or when the display was turned off (OFF), and a bright white display was obtained when the voltage was turned on (ON). In particular, bright and good visibility was obtained on the lower side (6 o'clock direction) in a direction orthogonal to the long side direction of the liquid crystal panel, and display unevenness such as streaks was not observed.

Comparative Example 1
A liquid crystal display device as a first comparative example of the present invention was manufactured. The liquid crystal display element of the first comparative example is a VA liquid crystal display element. The segment electrode and the common electrode that sandwich the liquid crystal layer are not provided with openings.

  First, in order to manufacture the liquid crystal display element of the 1st comparative example of this invention, a pair of glass substrate with an ITO film | membrane was prepared. One of the substrates was a first substrate having a segment electrode, and the other was a second substrate having a common electrode.

  In the liquid crystal display element of the first comparative example of the present invention, the segment electrode and the common electrode were patterned so as to correspond to an arbitrary display pattern.

  Next, a vertical alignment liquid crystal alignment film was formed on the segment electrode formation surface of the first substrate and the common electrode formation surface of the second substrate. Then, anti-parallel (antiparallel) rubbing treatment was performed on the liquid crystal alignment films on both the first substrate and the second substrate so as to be in a predetermined rubbing direction. Next, using the obtained alignment-treated first and second substrates, a VA liquid crystal panel was manufactured by sandwiching liquid crystal. A liquid crystal having a dielectric anisotropy (Δε) of −4.4 was used. The retardation (Δn · d) of the liquid crystal panel was set to 400 nm. The pretilt angle of the liquid crystal in the obtained liquid crystal panel was 89.6 degrees. Further, the rubbing direction of the liquid crystal panel is a direction orthogonal to the long side direction.

  Next, using the manufactured liquid crystal panel, a VA liquid crystal display element was manufactured by being sandwiched between a pair of polarizing plates including a first polarizing plate on the viewer side and a second polarizing plate on the non-viewer side. VHC-128UL2SZ-K1 made by Polatechno Co., Ltd. is used as the first polarizing plate, and 000R220N-VH39L2S (Re ≦ 7 nm, Rth = 220 nm, made by Polatechno Co., Ltd. is attached as the second polarizing plate. Polarizing plate) was used.

  At this time, assuming that the counterclockwise angle from the reference axis when viewed from the viewing side to the absorption axis of the F polarizing plate is θ1 with the long side direction of the liquid crystal panel as the reference axis, θ1 = 45 degrees. When the counterclockwise angle to the absorption axis of the R polarizing plate is θ2, θ2 = 135 degrees.

  When the liquid crystal display element manufactured as described above was used and driven at a duty ratio of 1/4, almost good visibility was obtained. That is, black display was obtained when no voltage was applied or when the display was turned off (OFF), and white display was obtained when the display was turned on by voltage application. In particular, good visibility was obtained on the lower side (6 o'clock direction) in the direction orthogonal to the long side direction of the liquid crystal panel. However, in the liquid crystal display element of this comparative example, display unevenness such as streaks was observed, and the display quality was significantly lowered.

Comparative Example 2
A liquid crystal display device as a second comparative example of the present invention was manufactured. The liquid crystal display element of the second comparative example is a VA type liquid crystal display element, and the opening of the electrode is formed in a rectangular shape compared to the liquid crystal display element of the first embodiment, and as a result, the electrode structure is different. ing.

  First, in order to manufacture the liquid crystal display element of the 2nd comparative example of this invention, a pair of glass substrate with an ITO film | membrane was prepared. One substrate was a first substrate having a segment electrode as a first electrode, and the other was a second substrate having a common electrode as a second electrode.

  In the liquid crystal display element of the second comparative example of the present invention, the segment electrode and the common electrode were patterned to form a plurality of substantially the same opening pattern, which were regularly arranged on each.

  Specifically, the opening of the segment electrode and the common electrode has a width of 16 μm in the direction orthogonal to the longitudinal direction (corresponding to the first direction in FIG. 1) (corresponding to the second direction in FIG. 1), and the opening Was formed to have a rectangular shape having a length of 100 μm and four inner angles of 90 degrees which are equal to each other. The opening structure of the electrode of the liquid crystal display element of the second comparative example of the present invention is the same as the opening structure of the electrode of the liquid crystal display element shown in FIG.

The distance between the openings adjacent in the longitudinal direction of the openings was 10 μm, and the distance between the openings adjacent in the width direction of the openings was 80 μm.
Also, in plan view, the opening of the common electrode on the anti-viewer side is shifted by 8 μm upward (12 o'clock direction) in parallel with the second direction with respect to the opening of the segment electrode on the viewer side. It was made to become the arrangement.

  In the liquid crystal display element of this comparative example, the long side direction of a liquid crystal panel, which will be described later, and the longitudinal direction of the openings of the segment electrodes and the common electrode are made parallel.

  Next, a vertical alignment liquid crystal alignment film was formed on the segment electrode formation surface of the first substrate and the common electrode formation surface of the second substrate, and a liquid crystal was sandwiched to manufacture a VA liquid crystal panel. A liquid crystal having a dielectric anisotropy (Δε) of −4.4 was used. The retardation (Δn · d) of the liquid crystal panel was set to 400 nm.

  Next, using the manufactured liquid crystal panel, a VA liquid crystal display element was manufactured by being sandwiched between a pair of polarizing plates including a first polarizing plate on the viewer side and a second polarizing plate on the non-viewer side. VHC-128UL2SZ-K1 made by Polatechno Co., Ltd. is used as the first polarizing plate, and 000R220N-VH39L2S (Re ≦ 7 nm, Rth = 220 nm, made by Polatechno Co., Ltd. is attached as the second polarizing plate. Polarizing plate) was used.

  At this time, assuming that the counterclockwise angle from the reference axis when viewed from the viewing side to the absorption axis of the F polarizing plate is θ1 with the long side direction of the liquid crystal panel as the reference axis, θ1 = 45 degrees. When the counterclockwise angle to the absorption axis of the R polarizing plate is θ2, θ2 = 135 degrees.

  When the liquid crystal display element manufactured as described above was used and driven at a duty ratio of 1/4, almost good visibility was obtained. That is, black display was obtained when no voltage was applied or when the display was turned off (OFF), and white display was obtained when the display was turned on by voltage application. In particular, good visibility was obtained on the lower side (6 o'clock direction) in the direction orthogonal to the long side direction of the liquid crystal panel. Further, display unevenness such as streaks was not visually recognized. However, in the liquid crystal display element of this comparative example, in the connection region between the openings adjacent to each other in the longitudinal direction of the opening in a plan view, liquid crystal orientation disorder is observed, light leakage is observed, and the contrast is reduced. The display quality has deteriorated.

  From the evaluation results of the second comparative example described above, in the first embodiment described above, the alignment state of the liquid crystal in the connection region between the openings adjacent in the longitudinal direction of the openings in plan view is preferable, and light leakage occurs. As a result, the contrast was improved, the display unevenness was not noticeable, and the display quality was improved.

Comparative Example 3
A liquid crystal display device as a third comparative example of the present invention was manufactured. The liquid crystal display element of the third comparative example is a VA liquid crystal display element. The segment electrode and the common electrode that sandwich the liquid crystal layer are not provided with openings. The liquid crystal display element of this comparative example has the same electrode structure as the liquid crystal display element of the first comparative example described above.

  A VA liquid crystal panel similar to that of the first comparative example was manufactured using the first substrate and the second substrate similar to those of the first comparative example, sandwiching the liquid crystal and excluding the liquid crystal described later.

  As the liquid crystal, a liquid crystal having a dielectric anisotropy (Δε) of −4.4 and 200 ppm added as an additive of TDA capable of reducing the specific resistance was used. The retardation (Δn · d) of the liquid crystal panel was set to 400 nm.

  Next, using the manufactured liquid crystal panel, a VA liquid crystal display element was manufactured by being sandwiched between a pair of polarizing plates including a first polarizing plate on the viewer side and a second polarizing plate on the non-viewer side. VHC-128UL2SZ-K1 made by Polatechno Co., Ltd. is used as the first polarizing plate, and 000R220N-VH39L2S (Re ≦ 7 nm, Rth = 220 nm, made by Polatechno Co., Ltd. is attached as the second polarizing plate. Polarizing plate) was used.

  At this time, assuming that the counterclockwise angle from the reference axis when viewed from the viewing side to the absorption axis of the F polarizing plate is θ1 with the long side direction of the liquid crystal panel as the reference axis, θ1 = 45 degrees. When the counterclockwise angle to the absorption axis of the R polarizing plate is θ2, θ2 = 135 degrees.

When the liquid crystal display element manufactured as described above was used and driven at a duty ratio of 1/4, almost good visibility was obtained. That is, black display was obtained when no voltage was applied or when the display was turned off (OFF), and white display was obtained when the display was turned on by voltage application. In particular, the visibility which becomes bright on the lower side (6 o'clock direction) in the direction orthogonal to the long side direction of the liquid crystal panel was obtained.
However, display irregularities such as streaks due to the rubbing treatment were observed, and the display quality was significantly reduced.

In the liquid crystal display element of this comparative example, the panel specific resistance was 4.3 × 10 ¹⁰ Ωcm. Then, when 10 kV static electricity was applied, it was found that the time until charging was canceled was within 30 seconds, which was a short time.

In addition, when the same evaluation was performed using the liquid crystal display element of the first comparative example, the panel specific resistance was 4.1 × 10 ¹¹ Ωm. When 10 kV of static electricity was applied, the charging was canceled. The time was 300 seconds or more.

  Furthermore, when the lighting evaluation was performed by changing the frame frequency from 70 Hz to 300 Hz using the liquid crystal display element of this comparative example, display unevenness was confirmed at all frame frequencies, and the display quality was lowered.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 2, 2a 1st electrode 3 1st board | substrate 4 2nd electrode 5 2nd board | substrate 6 Liquid crystal 7 Liquid crystal layer 8, 8a, 108 1st opening part 9, 109 2nd opening part 11 Diagonal electric field 12 Arrow indicating viewing angle direction

Claims (7)

Between the first substrate on which the first electrode is disposed, the second substrate on which the second electrode facing the first electrode is disposed, and between the first substrate and the second substrate And a liquid crystal display element having a liquid crystal layer in which the alignment of liquid crystal when no voltage is applied is a vertical alignment,
The first electrode has a plurality of first openings regularly arranged in a first direction;
The second electrode has a plurality of second openings regularly arranged in the first direction,
The first opening of the first electrode has a trapezoidal shape, and two parallel sides are parallel to the first direction, and are opposed to each other adjacent to the first direction. The sides are parallel to each other,
The second opening of the second electrode has a trapezoidal shape, and two parallel sides are parallel to the first direction, and are opposed to each other adjacent to the first direction. The sides are parallel to each other,
The first opening and the second opening are arranged in a plan view so that the first opening and the second opening are shifted in a second direction perpendicular to the first direction and are partially overlapped with each other. A characteristic liquid crystal display element.   A first polarizing plate disposed on a surface of the first substrate opposite to the surface of the first electrode; and a surface of the second substrate opposite to the surface of the second electrode disposed. A first polarizing plate and the second polarizing plate, the absorption axes of the first polarizing plate and the second polarizing plate are orthogonal to each other, and each has an angle of 45 degrees with the first direction. The liquid crystal display element according to claim 1, wherein the liquid crystal display element is arranged as described above.   The liquid crystal display element according to claim 1, wherein the first opening and the second opening have a width in the first direction of 8 μm to 30 μm.   4. The distance between adjacent ones of the plurality of first openings and the distance between adjacent ones of the plurality of second electrodes are 20 μm to 120 μm. 2. A liquid crystal display element according to item 1.   5. The liquid crystal display element according to claim 1, wherein each of the first opening and the second opening has an internal angle in a range of 40 degrees to 140 degrees. 6. The liquid crystal display element according to claim 1, wherein a specific resistance of the liquid crystal is in a range of 1 × 10 ¹⁰ Ωm to 2 × 10 ¹¹ Ωcm.   7. The alignment method according to claim 1, wherein at least one of the first substrate and the second substrate is subjected to an alignment treatment so that the liquid crystal is vertically aligned with a predetermined pretilt angle. The liquid crystal display element according to any one of the above.

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