WO2015046156A1 - Liquid crystal display element - Google Patents

Abstract

Provided is a liquid crystal display element having excellent display quality while reducing viewing angle dependency. This vertical-alignment liquid crystal display element includes a liquid crystal layer, an electrode (2F), and an electrode (2R). The electrode (2F) has slits (7) that extend along an axis (S1), and the electrode (2R) has slits (8) that extend along the axis (S1). In a prescribed pixel region formed in a region where the electrode (2F) and the electrode (2R) overlap, the slits (7) and the slits (8) are positioned in an alternating manner and arranged in a row along the axis (S1). In said pixel region, among the slits (7) and the slits (8) arranged in a row along the axis (S1), the slit located farthest toward one end and the slit located farthest toward the other end in the direction of the axis (S1) extend to the end parts of the electrodes upon which the respective slits are formed.

Description

Liquid crystal display element

The present invention relates to a liquid crystal display element, and more particularly, to a vertical alignment (VA (Vertical Alignment) type) liquid crystal display element.

As a VA-type liquid crystal display element, for example, Patent Document 1 discloses a liquid crystal display element in which a viewing angle dependency is reduced by providing a slit in a transparent electrode to control a direction in which liquid crystal molecules collapse.

The liquid crystal display element according to Patent Document 1 has a slit that is partially removed in a substantially rectangular shape in both transparent electrodes on a pair of substrates in a display region formed by the transparent electrodes on the pair of substrates. The slits provided in one transparent electrode and the slits provided in the other transparent electrode are alternately arranged in the direction perpendicular to the longitudinal direction of the slit in the display area. .

JP 2004-252298 A

As in the liquid crystal display element according to Patent Document 1, when a slit is provided in the transparent electrode in order to reduce the viewing angle dependency, if the slit is provided across the both ends of the transparent electrode, the electrode is divided, so the slit It is necessary to provide a slight clearance between the electrode ends. In such a place where the clearance is provided, the alignment control of the liquid crystal molecules is not successful, and the alignment unevenness L occurs as shown in FIG. Then, the edge of the pixel 5A displayed in the area where the transparent electrode overlaps is visually recognized, and the display is not good.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal display element having a good display appearance while reducing the viewing angle dependency.

In order to achieve the above object, the liquid crystal display element according to the present invention is
A liquid crystal layer, a pair of substrates facing each other with the liquid crystal layer interposed therebetween, a first electrode provided on one of the pair of substrates, and a second electrode provided on the other of the pair of substrates. A vertical alignment type liquid crystal display element,
The first electrode has a first slit extending along a predetermined axis when viewed from the normal direction of the pair of substrates.
The second electrode has a second slit extending along the axis when viewed from the normal direction,
Each of the first slit and the second slit is one or more,
In a predetermined pixel region formed in a region where the first electrode and the second electrode overlap when viewed from the normal direction, the first slit and the second slit along the axis Are arranged in a row with alternating positions,
Among the first slit and the second slit arranged in a line along the axis in the pixel region, the slit located on the most end side and the slit located on the other end side in the direction along the axis. To the end of the electrode where each slit is formed,
It is characterized by that.

According to the present invention, it is possible to provide a liquid crystal display element having a good display appearance while reducing the viewing angle dependency.

It is a schematic sectional drawing of the liquid crystal display element which concerns on one Embodiment of this invention. It is the figure which showed an example of the image which the liquid crystal display element which concerns on one Embodiment of this invention displays. It is a figure showing the shape of the electrode corresponding to the A section of the pixel shown in FIG. 2, and is a figure for demonstrating the slit formed in an electrode. FIG. 4 is a diagram corresponding to FIG. 3, where (a) is a plan view of a front side electrode and (b) is a plan view of a back side electrode. FIG. 4 is a schematic cross-sectional view taken along the line BB shown in FIG. (A) is the schematic sectional drawing which cut the liquid crystal display element which concerns on one Embodiment of this invention along the axis line shown in FIG. (B) is the schematic sectional drawing which cut the liquid crystal display element which concerns on a prior art example along the axis line shown in FIG. (A) And (b) is a top view of the electrode which concerns on a modification. It is a figure showing the shape of the electrode which concerns on a prior art example. It is a figure which shows the microscope picture of the pixel edge part of the conventional liquid crystal display element, and is a figure for demonstrating the alignment nonuniformity which had generate | occur | produced notably conventionally. It is a figure corresponding to FIG. 3, and is a figure for demonstrating the suitable width | variety of an edge part slit. (A)-(c) is a figure which shows the microscope picture of the pixel of a liquid crystal display element, (a) is a figure of the prior art example without an edge part slit, (b) is the width | variety of an edge part slit of 50 micrometers. (C) is a figure in case the width | variety of an edge part slit is 20 micrometers.

An embodiment of the present invention will be described with reference to the drawings.

(Configuration of the liquid crystal display element 100)
As shown in FIG. 1, the liquid crystal display element 100 according to an embodiment of the present invention includes a liquid crystal cell 10 and polarizing plates 20 and 30. The liquid crystal display element 100 displays a predetermined image by appropriately switching a pixel to be described later to a transmissive / non-transmissive state. Hereinafter, as illustrated in FIG. 1, a user (viewer of a displayed image) side from a predetermined member will be described as a front side, and the opposite side will be appropriately described as a back side.

The liquid crystal cell 10 is a vertical alignment type (VA type) liquid crystal cell. As shown in FIG. 1, a pair of front substrate 1F and back substrate 1R, electrodes 2F, 2R, alignment films 3F, 3R, and liquid crystal And a layer 4.

The front side substrate 1F and the back side substrate 1R are each formed of, for example, glass, plastic or the like transparently. The front substrate 1F and the back substrate 1R are arranged to face each other with the liquid crystal layer 4 interposed therebetween. The front substrate 1 </ b> F is located on the front side of the liquid crystal cell 10, and the back substrate 1 </ b> R is located on the back side of the liquid crystal cell 10.

The electrodes 2F and 2R are each composed of an ITO (Indium Tin Oxide) film or the like mainly composed of indium oxide, and are transparent electrodes that transmit light. The electrode 2F is formed on the surface of the front substrate 1F on the liquid crystal layer 4 side, and the electrode 2R is formed on the surface of the back substrate 1R on the liquid crystal layer 4 side by a known method (sputtering, vapor deposition, etching, etc.). The electrode 2F is configured as a common electrode, and the electrode 2R is configured as a segment electrode. A voltage is applied to both electrodes by a passive drive system. That is, the liquid crystal display element 100 is a segment display type and configured as a passive drive type liquid crystal display element. The electrode 2R may be configured as a segment electrode, and the electrode 2F may be configured as a common electrode.
Further, the electrodes 2F and 2R are formed to have slits unique to the present embodiment. This will be described in detail later.

The electrodes 2F and 2R are each patterned in a predetermined shape. The liquid crystal display element 100 has the predetermined shape in a region where the electrode 2F and the electrode 2R overlap as viewed from the normal direction of the opposing surfaces of the front substrate 1F and the back substrate 1R (hereinafter simply referred to as the substrate normal direction). Pixels corresponding to are displayed. Here, the pixel is an element of an image displayed by the liquid crystal display element 100, and includes not only a figure but also a single element representing a symbol such as a character, a number, or an icon. The liquid crystal display element 100 transmits light in the region where the on-voltage is applied to the liquid crystal layer 4 through the electrodes 2F and 2R, thereby bringing the pixels corresponding to the region into a display state (displaying substantially white). . The liquid crystal display element 100 is configured as a so-called negative display type (normally black mode) in which pixels are displayed substantially white on a substantially black background region.

An example of an image displayed on the liquid crystal display element 100 is shown in FIG. In the figure, the liquid crystal display element 100 is configured as a 7-segment display and displays an image indicating a numerical value (in the figure, “8” is displayed). In this example, there are seven pixels 5 (segments) representing a figure, and a numerical value is displayed by a combination thereof. In the liquid crystal display element 100, when viewed from the substrate normal direction, a region where the electrode 2F and the electrode 2R do not overlap and a region where no on-voltage is applied are substantially black background regions 6. In FIG. 2, the routing electrode formed in the background region 6 is omitted.

The alignment films 3F and 3R are each a vertical alignment film in contact with the liquid crystal layer 4, and are formed from, for example, polyimide by a known method (for example, flexographic printing). The alignment film 3F covers the electrode 2F from the liquid crystal layer 4 side, and the alignment film 3R covers the electrode 2R from the liquid crystal layer 4 side. The alignment films 3F and 3R are arranged such that liquid crystal molecules when no voltage is applied to the liquid crystal layer 4 from the electrodes 2F and 2R (when no voltage is applied) are used as main surfaces (on the liquid crystal layer 4 side) of the front substrate 1F and the back substrate 1R. Oriented substantially perpendicular to the surface facing the surface.

The liquid crystal layer 4 is sealed in a space formed by the front substrate 1F, the back substrate 1R, and a sealing material (not shown) that joins both substrates. The liquid crystal layer 4 is made of a liquid crystal material having a negative dielectric anisotropy Δε (Δε <0). Further, the layer thickness (cell gap) of the liquid crystal layer 4 is kept constant by a spacer (not shown). When a voltage equal to or higher than the threshold voltage is applied to the liquid crystal layer 4, the liquid crystal molecules that are aligned substantially vertically behave like falling down. When an on-voltage is applied, the liquid crystal molecules are substantially parallel to the main surfaces of both substrates (the front side substrate 1F and the back side substrate 1R).

The polarizing plates 20 and 30 emit light incident from one surface side as linearly polarized light along a transmission axis perpendicular to the absorption axis from the other surface side. As shown in FIG. 1, the polarizing plate 20 is located on the front side of the liquid crystal cell 10, and the polarizing plate 30 is located on the back side of the liquid crystal cell 10. The polarizing plate 20 and the polarizing plate 30 are arranged so that their absorption axes are orthogonal to each other when viewed from the normal direction of the substrate (orthogonal Nicol arrangement). As the polarizing plates 20 and 30, for example, SHC-13U (manufactured by Polatechno Co., Ltd.), which is a dye-based polarizing film, can be used.
A back light (not shown) is provided on the back side of the polarizing plate 30. The liquid crystal display element 100 performs transmissive display with light from a backlight. A control device (not shown) is connected to the electrode 2F and the electrode 2R. This control device applies an on-voltage / off-voltage to the electrodes 2F, 2R as appropriate by a passive drive method, and switches the pixel to a transmission / non-transmission state, thereby allowing the liquid crystal display element 100 to be a single pixel or a group of pixels. A predetermined image represented by is displayed.

In the liquid crystal display element 100, the off voltage is set to a value lower than the threshold voltage at which the liquid crystal molecules start to fall. Therefore, even when an off voltage is applied to the liquid crystal layer 4, the liquid crystal molecules remain substantially vertically aligned. In this case, the polarization direction of the light emitted from the backlight and passing through the polarizing plate 30 is hardly changed by the liquid crystal layer 4. Therefore, most of the light transmitted through the liquid crystal cell 10 from the back side cannot pass through the polarizing plate 20 arranged in a relationship of crossed Nicols with the polarizing plate 30. Therefore, the display of the region to which the off voltage is applied is visually recognized as black (normally black mode). On the other hand, when an on-voltage is applied to the liquid crystal layer 4, the liquid crystal molecules in the region to which the on-voltage is applied behaves so as to be substantially parallel to the substrate main surface of the liquid crystal cell 10. Thereby, birefringence occurs in the light transmitted through the liquid crystal layer 4, the polarization direction of the light changes, and the light transmitted through the liquid crystal cell 10 from the back side is transmitted through the polarizing plate 20. Therefore, the region where the on-voltage is applied is in the transmissive display state.

(About slits)
From here, the slit formed in electrode 2F, 2R is demonstrated in detail.
FIG. 3 is a front view of the electrodes 2F and 2R in a region corresponding to the A portion of the pixel shown in FIG. 4A shows the electrode 2F located on the front side of the electrodes shown in FIG. 3, and FIG. 4B shows the electrode 2R located on the back side among the electrodes shown in FIG. FIG. In these drawings, the electrode 2F is represented by a solid line, and the electrode 2R is represented by a dotted line.

As shown in FIGS. 3 and 4A, the electrode 2F provided on the front substrate 1F has a slit 7 extending along a predetermined axis when viewed from the normal direction of the substrate. As shown in FIGS. 3 and 4B, the electrode 2R provided on the back substrate 1R has a slit 8 extending along a predetermined axis when viewed from the normal direction of the substrate. The slit 7 is a hole that penetrates the electrode 2F in the substrate normal direction, and the slit 8 is a hole that penetrates the electrode 2R in the substrate normal direction, and each is formed in a substantially rectangular shape when viewed from the substrate normal direction. Has been.

In this embodiment, as shown in FIG. 3, one of the slit 7 and the slit 8 is one on the predetermined one axis, and the other is two. Then, when viewed from the normal direction of the substrate, in the region of the predetermined pixel 5 formed in the region where the electrodes 2F and 2R overlap, the slits 7 and the slits 8 are alternately positioned along the predetermined one axis. And lined up in a row. Further, in the region of the predetermined pixel 5, among the slit 7 and the slit 8 arranged in a line along a predetermined one axis, the slit located on the most end side in the direction along the axis and the position on the most other side The slit to be reached reaches the end of the electrode in which each slit is formed. More specific description will be given below.

Referring to FIG. 3, when attention is paid to the axis S1, there are two slits 7 and one slit 8 on the axis S1. The slits 7 and 8 are alternately arranged along the axis S1 and arranged in a line, and the slit 7 located on the most end side (for example, the upper end side in the figure) along the axis S1 is shown in FIG. As shown in (a), the slit 7 that reaches the end (upper end in the figure) of the front electrode 2F and is located on the other end side in the direction along the axis S1 (for example, lower end in the figure) As shown to Fig.4 (a), it has reached to the edge part (lower end part in a figure) of the electrode 2F of the front side. Thereby, as shown in FIG. 4A, a notch-shaped slit 7 is formed at one end and the other end along the axis S1 of the front electrode 2F. Further, as shown in FIG. 4B, an open slit 8 is formed at the center of the width in the direction of the axis S1 of the electrode 2R on the back side.

Referring to FIG. 3, when attention is paid to the axis S2, there are two slits 8 and one slit 7 on the axis S2. The slits 7 and 8 are alternately arranged along the axis S2 and arranged in a line, and the slit 8 located on the most end side (for example, the upper end side in the figure) along the axis S2 is shown in FIG. As shown in (b), the slit 8 that reaches the end (upper end in the figure) of the electrode 2R on the back side and is located on the other end side in the direction along the axis S2 (for example, the lower end side in the figure) As shown in FIG.4 (b), it has reached to the edge part (lower end part in a figure) of the electrode 2R on the back side. Thus, as shown in FIG. 4B, a notch-shaped slit 8 is formed at one end and the other end along the axis S2 of the back electrode 2R. Moreover, as shown to Fig.4 (a), the slit 7 which opened was formed in the center part of the width | variety of the axis line S2 direction of the electrode 2F of the front side.
Similarly, as shown in FIG. 3, the slit 7, slit 8, and slit 7 are formed on the axis S3 in order from the upper side in the figure, and the slit 8, slit 7, and slit 8 are formed on the axis S4. The slit 7, slit 8, and slit 7 are formed on the axis S5.

Further, when viewed from the normal direction of the substrate, the slits 7 and the slits 8 which are adjacent to each other along a predetermined one axis are arranged without being spaced from each other. For example, referring to FIG. 3, focusing on the axis S <b> 1, the lower end of the slit 7 located on the upper side in the drawing on the axis S <b> 1 comes into contact with the upper end of the slit 8 when viewed from the substrate normal direction. ing. Further, the upper end of the slit 7 positioned on the lower side in the drawing on the axis S1 is in contact with the lower end of the slit 8 when viewed from the normal direction of the substrate.

In addition, the slits 7 and the slits 8 arranged alternately in a line along a predetermined one axis are as if they were one slit when viewed from the normal direction of the substrate. If this is the slit group 9, as shown in FIG. 3, the adjacent slit groups 9 are arranged at a predetermined interval in a direction perpendicular to the direction of the axis along which they are adjacent. For example, the slit group 9 along the axis S1 is disposed at a predetermined interval in the direction perpendicular to the axis S1 and the axis S2 from the slit group 9 along the axis S2. In this embodiment, the slits located on the most end side and the other end side in the direction along the predetermined one axis are formed to have the same length. For example, the two slits 7 along the axis S1 have the same length in the direction of the axis S1, and the two slits 8 along the axis S2 are also formed to have the same length as the slit 7 along the axis S1.

Hereafter, the effect of the liquid crystal display element 100 having the electrode in which the slit is formed as described above will be described in comparison with the conventional example. The shape of the electrode of the liquid crystal display element which concerns on a prior art example is shown in FIG. For ease of understanding, the same reference numerals as those of the liquid crystal display element 100 are assigned to the portions of the liquid crystal display element according to the conventional example shown in FIG. did.

FIG. 5 is a schematic cross-sectional view taken along the line BB of FIG. 3 of the liquid crystal display element 100, and schematically shows the electric field E generated between the electrode 2F and the electrode 2R and the liquid crystal molecules 4A of the liquid crystal layer 4. is there. Here, for easy understanding, appropriate members are omitted (the same applies to FIGS. 6A and 6B described later).
By forming the slits 7 and 8, an oblique electric field E as shown in FIG. 5 is generated. Thus, in the region D1, when a voltage is applied, the liquid crystal molecules 4A that are aligned substantially vertically are tilted counterclockwise in the drawing (so that the long axis of the liquid crystal molecules 4A is orthogonal to the oblique electric field E). Behave). Then, in the region D1, the best viewing direction is from the upper right direction in the figure, and the direction with poor visibility is from the upper left direction in the opposite figure. In the region D2, when a voltage is applied, the liquid crystal molecules 4A that are aligned substantially vertically are tilted clockwise in the drawing. Then, in the region D2, the best viewing direction is from the upper left direction in the figure, and the direction with poor visibility is from the upper right direction in the opposite figure. As described above, the direction in which the visibility of the region D1 is poor matches the best viewing direction of the region D2, and the direction in which the visibility of the region D2 is poor matches the best viewing direction of the region D1, so the regions D1 and D2 And complement the viewing angle dependency. As described above with reference to FIG. 3, the slit group 9 is continuously arranged at a predetermined interval in a direction orthogonal to the direction in which the slit group 9 extends, and thus is similar to the relationship between the region D1 and the region D2. Adjacent areas that have the same relationship appear continuously. With this configuration, a so-called multi-domain structure is obtained, and as a result, the viewing angle dependency of the entire pixel region is reduced. This also applies to the conventional example shown in FIG.

Next, a description will be given with reference to FIG. 6A and FIG. FIG. 6A is a schematic cross-sectional view of the liquid crystal display element 100 according to the present embodiment taken along the axis S1 shown in FIG. FIG. 6B is a schematic cross-sectional view of the liquid crystal display element according to the conventional example cut along the axis S1 shown in FIG.
First, referring to FIG. 6B, the electric field E is oblique at the left and right ends (corresponding to the upper end and the lower end along the axis S1 in FIG. 8) of the electrodes 2F and 2R in the conventional example. do not become. That is, in the configuration of the conventional example, the tilt direction of the liquid crystal molecules 4A at the pixel end cannot be controlled by the oblique electric field. For this reason, the liquid crystal molecules 4A at the pixel end part collapse in an orderly manner in both the clockwise direction and the counterclockwise direction in FIG. 6B when a voltage is applied. When the liquid crystal molecules 4A behave in this manner, the alignment unevenness L as shown in FIG. 9 occurs, and the end of the pixel 5A is visually recognized.
On the other hand, in the liquid crystal display element 100 according to the present embodiment, as shown in FIG. 6A, in the drawing, at the left and right ends (corresponding to the upper end and the lower end along the axis S1 in FIG. 3), An oblique electric field E is generated. As a result, the liquid crystal molecules 4A at the end of the pixel behave so that the oblique electric field E and the major axis thereof are orthogonal to each other when a voltage is applied, and the direction in which the liquid crystal molecule 4A falls is controlled. For example, when attention is paid to the liquid crystal molecules 4A at the left end in FIG. 6A, the liquid crystal molecules 4A, which are aligned substantially vertically, are inclined almost uniformly counterclockwise in the figure when a voltage is applied. Become. Here, the behavior of the liquid crystal molecules 4A at the electrode ends along the axis S1 has been described, but the same applies to the electrode ends along the other axes S2, S3, and the like. For this reason, according to the structure of the electrodes 2F and 2R having the slits 7 and 8 according to the present embodiment, it is possible to satisfactorily reduce the alignment unevenness generated at the end of the pixel.
That is, according to the liquid crystal display element 100 according to the present embodiment, it is possible to reduce the alignment unevenness at the end of the pixel while reducing the viewing angle dependency, and the display quality is good.

From here, a preferred embodiment of forming the slits 7 and 8 will be described with reference to FIGS. 10 and 11A to 11C. Hereinafter, among the slits 7 and 8 arranged in a line along a predetermined axis, slits positioned at both ends in the direction along the axis are referred to as “end slits”.

Referring to FIG. 10, in the rightmost slit group 9 in the figure (corresponding to the slit group 9 on the axis S5 in FIG. 3), the end slit 7A, the slit 8, and the end slit 7B are positioned in order from the upper side in the figure. To do. The end slit 7A is located on the most end side in the direction along the axis, and the end slit 7B is located on the other end side in the direction along the axis. The end slits 7A and 7B are formed in the front electrode 2F.
Further, in the adjacent slit group 9 (corresponding to the slit group 9 on the axis S4 in FIG. 3), an end slit 8A, a slit 7, and an end slit 8B are located in order from the upper side in the drawing. The end slit 8A is located on the most end side in the direction along the axis, and the end slit 8B is located on the other end side in the direction along the axis. The end slits 8A and 8B are formed in the back electrode 2R. The same applies to the other slit groups 9.

When the end slit is defined as described above, the width W of the end slit in the direction orthogonal to the electrode end from the electrode end where the end slit is formed (hereinafter simply referred to as “the width W of the end slit”). Is preferably 10 μm or more and 50 μm or less (10 μm ≦ W ≦ 50 μm).
That is, the end slit 7A preferably satisfies the condition that the width W from the end of the electrode 2F in the direction orthogonal to the end of the electrode 2F is 10 μm or more and 50 μm or less.
Similarly, the end slit 7B preferably satisfies the condition that the width W from the end of the electrode 2R in the direction orthogonal to the end of the electrode 2R is 10 μm or more and 50 μm or less.
Hereinafter, how the present inventor found this condition will be described.

FIGS. 11 (a) to 11 (c) show photographs at the time of applying an on-voltage of three types of liquid crystal display elements in which the conditions of slits formed in the electrodes are changed. These are enlarged photographs of predetermined pixels (segments). FIG. 11A shows a liquid crystal display element having electrodes (electrodes without end slits) according to the conventional example shown in FIG. FIG. 11B shows the liquid crystal display element 100 in which the width W of the end slit is set to 50 μm. FIG. 11C shows the liquid crystal display element 100 in which the width W of the end slit is set to 20 μm.

In the liquid crystal display elements shown in FIGS. 11A to 11C, the interval between adjacent slits in the horizontal direction of FIGS. 8 and 10 is set to 40 μm, and the width of each slit (the above-mentioned “end slit width W”). ”, The width of each slit in the horizontal direction of FIG. 8 and FIG. 10 is 15 μm, the retardation (Δnd) of the liquid crystal layer 4 is 350 nm, and the viewing angle compensation plate is between the liquid crystal cell 10 and the polarizing plates 20 and 30. Inserted.
Further, in the example shown in FIGS. 11B and 11C, the end slits 7A and 7B formed in the electrode 2F and the end slits 8A and 8B formed in the electrode 2R are all fixed width W. It is formed with.

In FIGS. 11 (a) to 11 (c), a vertically extending streak visually recognized inside the pixel is a slit formed in the electrode. A substantially rectangular shape (substantially elliptical shape) that is visually recognized at the pixel end (electrode end) and extends vertically is the alignment unevenness (alignment defect) L.
First, referring to FIG. 11A, it can be seen that in the conventional example, the alignment unevenness L generated at the pixel end is remarkably generated. When the alignment unevenness L occurs in this way, the pixel end is visually recognized as a jagged edge, which causes a deterioration in display appearance.
Next, referring to FIG. 11B, when the end slit is formed in the electrode and the width W is set to 50 μm, each of the alignment unevenness L generated at the pixel end is smaller than in the conventional example. You can see that Thereby, it can suppress that the pixel end is visually recognized.
Furthermore, referring to FIG. 11C, when an end slit is formed in the electrode and the width W is set to 20 μm, each of the alignment unevenness L generated at the pixel end is further reduced, and the pixel It can be seen that they are distributed evenly along the edges. Thereby, it can suppress more favorably that the pixel end is visually recognized.

From the above consideration, it can be understood that the smaller the width W of the end slit, the better from the viewpoint of the appearance of display. However, if the width W of the end slit is too small, it is difficult to pattern ITO, and the possibility that the electrode is divided increases.
For example, focusing on the slit group 9 located on the rightmost side in FIG. 10, the smaller the width W of the end slits 7A and 7B of the electrode 2F is, the smaller the slit 8 of the electrode 2R formed between them. It will be understood that the electrode 2R becomes closer to the end of the electrode 2R, and the possibility that the electrode 2R is divided by the slit 8 is increased.
Therefore, the inventor of the present application sets the lower limit of the width W of the end slit to 10 μm in consideration of the range in which the electrode patterning can be realized and the range in which the electrode is not easily divided.

On the other hand, as the width W of the end slit is increased, it is assumed from the observation results of FIGS. 11B and 11C that the effect of reducing the alignment unevenness L is reduced.
This is because, depending on the shape of the pixel, when the angle formed between the edge of the pixel and the direction in which the slit extends becomes more acute, the distance between the ends of the adjacent slits increases. This is considered to be because the effect of controlling the alignment of the liquid crystal by the slits is diminished because the interval between the matching slits is widened. For example, referring to FIG. 11B, although the alignment unevenness L does not occur so much on the upper and lower sides of the pixel, the upper and lower sides of the pixel are on the left and right sides of the pixel where the angle formed with the direction in which the slit extends is more acute. It can also be inferred from the fact that the alignment unevenness L is likely to occur as compared with FIG.
Therefore, the inventors set the upper limit of the width W of the end slit to 50 μm in consideration of the range in which the effect of reducing the alignment unevenness L can be confirmed by visual recognition.

In the above description, the end slits 7A and 7B formed on the front electrode 2F and the end slits 8A and 8B formed on the back electrode 2R are all the same width. It is also possible to vary the width. However, as shown in FIG. 10, when the widths of the end slits are all the same, the end slits for reducing the alignment unevenness L can be formed uniformly along the pixel ends. It is considered that it is possible to more effectively suppress the pixel end from being visually recognized.

In addition, this invention is not limited by said embodiment and drawing. It goes without saying that changes (including deletion of components) can be added to the above embodiments and drawings.

In the above embodiment, as shown in FIG. 3, an example in which one of the slit 7 and the slit 8 is one and the other is two on a predetermined axis is shown. There may be a plurality of slits 7 and slits 8 on the line.
Further, as shown in FIG. 7A, there may be one slit 7 and one slit 8 on a predetermined one axis. Even in such a case, it can be said that the slits 7 and the slits 8 are alternately arranged along a predetermined one axis line. In addition, the slit 7 located on the axis S1 in FIG. 7A and the slit 8 located on the axis S2 can also be considered as end slits as described above. In this case as well, the end slits are formed. It is preferable that the width of the end slit in the direction orthogonal to the electrode end from the electrode end being 10 to 50 μm.

Further, in the above embodiment, as shown in FIG. 3, the slits 7 and 8 adjacent to each other are aligned so as to be in contact with each other along a predetermined axis when viewed from the normal direction of the substrate. However, the present invention is not limited to this. As shown in FIG. 7B, the slits 7 and the slits 8 adjacent to each other along a predetermined one axis may be partially overlapped when viewed from the normal direction of the substrate. In such a mode as well, it can be said that the slits 7 and the slits 8 adjacent to each other along the predetermined one axis line are arranged without a space when viewed from the normal direction of the substrate.
Further, as long as the effect of reducing the alignment unevenness at the end of the pixel is reduced while reducing the viewing angle dependency, the slits adjacent to each other along the predetermined one axis as viewed from the substrate normal direction. 7 and the slit 8 may be spaced apart slightly. However, if the interval is too large, the tilting electric field cannot satisfactorily control the direction in which the liquid crystal molecules 4A are tilted, resulting in a location. Therefore, the slits 7 and 8 adjacent to each other along the predetermined one axis line. The smaller the interval, the better.

In the above description, in order to facilitate the understanding of the present invention, explanations of known unimportant technical matters are appropriately omitted.

The present invention is suitable for a liquid crystal display element, and more specifically, for a vertical alignment type (VA (Vertical Alignment) type) liquid crystal display element.

DESCRIPTION OF SYMBOLS 100 ... Liquid crystal display element 10 ... Liquid crystal cell 1F ... Front side board | substrate 1R ... Back side board | substrate 2F, 2R ... Electrode 3F, 3R ... Orientation film 4 ... Liquid crystal layer 4A ... Liquid crystal molecule 5, 5A ... Pixel 6 ... Background area 7, 8 ... Slit 7A, 7B, 8A, 8B ... end slit 9 ... slit group 20, 30 ... polarizing plate E ... electric field L ... orientation unevenness

Claims (4)

1. A liquid crystal layer, a pair of substrates facing each other with the liquid crystal layer interposed therebetween, a first electrode provided on one of the pair of substrates, and a second electrode provided on the other of the pair of substrates. A vertical alignment type liquid crystal display element,
   The first electrode has a first slit extending along a predetermined axis when viewed from the normal direction of the pair of substrates.
   The second electrode has a second slit extending along the axis when viewed from the normal direction,
   Each of the first slit and the second slit is one or more,
   In a predetermined pixel region formed in a region where the first electrode and the second electrode overlap when viewed from the normal direction, the first slit and the second slit along the axis Are arranged in a row with alternating positions,
   Among the first slit and the second slit arranged in a line along the axis in the pixel region, the slit located on the most end side and the slit located on the other end side in the direction along the axis. To the end of the electrode where each slit is formed,
   A liquid crystal display element.
2. The first slit and the second slit adjacent to each other along the axis as viewed from the normal direction are arranged without a gap between them.
   The liquid crystal display element according to claim 1.
3. In the pixel region, when the slit located on the most end side in the direction along the axis among the first slit and the second slit arranged in a line along the axis is an end slit,
   When viewed from the normal direction, the width of the end slit in the direction orthogonal to the electrode end from the electrode end where the end slit is formed is 10 μm or more and 50 μm or less.
   The liquid crystal display element according to claim 2.
4. When viewed from the normal direction, each of the first slit and the second slit has a substantially rectangular shape extending in a direction along the axis.
   The liquid crystal display element according to claim 1, wherein the liquid crystal display element is a liquid crystal display element.

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