JP2009151204A - Liquid crystal display device - Google Patents

Liquid crystal display device Download PDF

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JP2009151204A
JP2009151204A JP2007330676A JP2007330676A JP2009151204A JP 2009151204 A JP2009151204 A JP 2009151204A JP 2007330676 A JP2007330676 A JP 2007330676A JP 2007330676 A JP2007330676 A JP 2007330676A JP 2009151204 A JP2009151204 A JP 2009151204A
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liquid crystal
direction
crystal display
display device
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Japanese (ja)
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Yuki Kawashima
Yasutoshi Tasaka
Hiroshi Yoshida
裕志 吉田
由紀 川島
泰俊 田坂
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Sharp Corp
シャープ株式会社
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Abstract

A high-quality liquid crystal display device having high transmittance is provided.
[Solution]
The liquid crystal display device according to the present invention is a vertical alignment type liquid crystal display device including a plurality of pixels 10, and supplies a pixel electrode 30 disposed in each of the plurality of pixels 10 and a display signal. A first substrate having a signal line 23a extending in a first direction, a second substrate having a common electrode facing the pixel electrode 30, and a first substrate and a second substrate. The pixel electrode 10 includes a trunk portion 30b, a first fringe portion 30ea, a second fringe portion 30ec, and a trunk portion 30b, each extending in the first direction. A plurality of first branch portions 30ca extending in a second direction different from the first direction between the first fringe portion 30ea and the first direction and the second direction between the trunk portion 30b and the second fringe portion 30ec. A plurality of extending in different third directions And a second branch part 30da.
[Selection] Figure 1

Description

  The present invention relates to a liquid crystal display device, and more particularly to a vertical alignment type liquid crystal display device having a plurality of alignment division regions in a pixel.

  Currently, as a liquid crystal display device having a wide viewing angle characteristic, a liquid crystal display device using a lateral electric field mode IPS (In-Plane-Switching) mode or FFS (Fringe Field Switching) mode, and a vertical alignment mode VA ( A liquid crystal display device using a vertical alignment mode has been developed. Since the VA mode is more mass-productive than the horizontal electric field mode, it is widely used for TV applications and mobile applications (see Patent Document 1).

  The VA mode liquid crystal display device includes an MVA (Multidomain Vertical Alignment) mode liquid crystal display device (see Patent Document 2) in which a plurality of domains having different liquid crystal alignment directions are formed in one pixel, and the center of the pixel. The liquid crystal display device is roughly classified into a CPA (Continuous Pinwheel Alignment) mode liquid crystal display device in which the alignment direction of the liquid crystal is continuously changed around a rivet or the like formed on the electrode of the portion.

  In the MVA mode liquid crystal display device, by arranging the alignment regulating means extending in two directions orthogonal to each other, the polarization axis (transmission axis) of the pair of polarizing plates arranged in crossed Nicols in one pixel. Thus, four liquid crystal domains having an azimuth angle of 45 degrees representing the liquid crystal domain are formed. Assuming that the azimuth angle of 0 degree is the direction of the polarization axis of one polarizing plate and the counterclockwise direction is a positive azimuth direction, the director angles of these four liquid crystal domains are 45 degrees, 135 degrees, 225 degrees, and 315 degrees. It becomes. Since linearly polarized light in the direction of 45 degrees with respect to the polarization axis is not absorbed by the polarizing plate, it is most preferable from the viewpoint of transmittance to select such an azimuth angle of the director. In this manner, a configuration in which four domains are formed in one pixel is referred to as a four-divided alignment structure or simply a 4D structure.

  The MVA mode liquid crystal display device is not suitable for a small pixel (for example, a short side of less than 100 μm, particularly less than 60 μm). For example, when a slit (or rib) is used as the orientation regulating means, the slit width needs to be about 10 μm or more in order to obtain a sufficient orientation regulating force, and if the slit width is narrower than this, A sufficient alignment regulating force cannot be obtained. In order to form four domains, slits (shaped slits) extending in directions different from each other by 90 degrees when viewed from the normal direction of the substrate are formed in one counter pixel, and these slits are formed. It is necessary to form slits in the pixel electrode that are arranged with a certain distance from each other and extend in parallel with these slits. That is, it is necessary to arrange a plurality of slits each having a width of about 10 μm extending in the 45 ° -225 ° direction and the 135 ° -315 ° direction on both the counter electrode and the pixel electrode in one pixel.

  However, when the slit as described above is applied to a pixel having a short side of less than 100 μm, the area occupied by the slit increases with respect to the pixel area, and the area that cannot be contributed to the display also increases. To drop. Further, in a high-definition small-sized liquid crystal display device such as a 2.4-inch VGA for a mobile phone, the pixel pitch (row direction × vertical direction) is, for example, 25.5 μm × 76.5 μm. Even the slits described above can no longer be formed.

  On the other hand, in the CPA mode liquid crystal display device, a rivet made of resin or the like is formed at the pixel central portion of the counter electrode, and the alignment of the liquid crystal is regulated by this rivet and an oblique electric field generated at the edge portion of the pixel electrode. A quarter-wave plate (quarter-wave plate) is disposed between each of the two polarizing plates and the liquid crystal layer, and is high by using omnidirectional radial tilt alignment domains and circularly polarized light. Transmittance (luminance) is obtained.

  Although the CPA mode using a quarter wave plate has high transmittance, it has a problem that the contrast ratio is low and the viewing angle is narrow compared to the MVA mode. In other words, when a quarter-wave plate is used, the display (particularly, low gradation (low luminance) display) appears brighter at an oblique viewing angle than when observed from the front (display surface normal direction (viewing angle 0 degree)). The so-called “white float” becomes prominent.

  In order to solve the problems of the MVA mode and CPA mode liquid crystal display devices, a liquid crystal display device as disclosed in Patent Document 3 has been proposed. In the liquid crystal display device of Patent Document 3, many fine slits extending in the 45 ° -225 ° direction and 135 ° -315 ° direction are put in the pixel electrode (referred to as fishbone pixel electrodes). By aligning the liquid crystals in parallel, a quadrant alignment structure is realized. In the liquid crystal display device using the fishbone pixel electrode, wide slits and rivets are not formed in the pixel, and linearly polarized light is used without using a quarter-wave plate, so that the transmittance and contrast ratio are high. In addition, display with a wide viewing angle can be realized.

In these liquid crystal display devices, an alignment maintaining layer for providing an appropriate pretilt angle to the liquid crystal in a state where no voltage is applied to the liquid crystal is disposed on the surface of the upper and lower substrates on the liquid crystal layer side. The alignment maintaining layer is formed by polymerizing the monomer contained in the liquid crystal layer while applying a voltage to the liquid crystal.
JP 2000-305100 A JP 2002-229038 A JP 2003-149647 A

  FIG. 5 is a plan view schematically showing a part of the pixel electrode of the liquid crystal display device described in Patent Document 3. As shown in FIG.

  As shown in FIG. 5, the pixel electrode 90 of Patent Document 3 includes a trunk portion 90a extending in the 0-180 degree direction (left-right direction in FIG. 5) and a trunk portion 90b extending in the 90-180 degree direction in the pixel 10 ′. The plurality of branch portions 90c extending from the trunk portion 90a or 90b in the direction of 45 to 225 degrees and the plurality of branch portions 90d extending in the direction of 135 to 315 degrees are provided. On the right side of the pixel electrode 90, a signal line (source bus line) 95 extends in parallel with the trunk 90b.

  The ends of the plurality of branches 90c and 90d are all disconnected at the periphery of the pixel and are not connected to other electrode members. In other words, slits (portions where no electrode members are arranged) formed between any two of the plurality of branch portions 90c and between any two of the plurality of branch portions 90d are all pixel peripheral portions. It is a slit opened toward Therefore, the liquid crystal molecules located near the open end of the slit (near the electrode edge) are relatively strongly affected by the electric field formed by the signal line 95 (see the broken line arrow in FIG. 5).

  The liquid crystal molecules affected by the unnecessary electric field in this way have their alignment direction shifted from the desired alignment direction (the direction parallel to the slit when white is displayed), or the alignment direction is not constant. There is a problem in that display unevenness or gradation abnormality occurs.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a liquid crystal display device having a desired high transmittance and high display quality.

  A liquid crystal display device according to the present invention is a vertical alignment type liquid crystal display device including a plurality of pixels, for supplying a pixel electrode disposed in each of the plurality of pixels and a display signal. A first substrate having a signal line extending in a first direction; a second substrate having a common electrode facing the pixel electrode; and a negative electrode disposed between the first substrate and the second substrate. A liquid crystal layer including a liquid crystal having a dielectric anisotropy of, and the pixel electrode includes a trunk portion, a first fringe portion, and a second fringe portion, each extending in the first direction, the trunk portion, and the first portion. A plurality of first branch portions extending in a second direction different from the first direction with respect to one fringe portion; and the first direction and the second direction between the trunk portion and the second fringe portion. A plurality of second branch portions extending in different third directions.

  In one embodiment, the pixel electrode includes a plurality of third branch portions extending in the second direction between the trunk portion and the second fringe portion, and the first electrode portion between the trunk portion and the first fringe portion. A plurality of fourth branch portions extending in three directions.

  In one embodiment, the plurality of first branch portions, the plurality of second branch portions, the plurality of third branch portions, and the plurality of fourth branch portions have substantially the same width.

  In one embodiment, widths of the plurality of first branch portions, the plurality of second branch portions, the plurality of third branch portions, and the plurality of fourth branch portions are 1.4 μm or more and 8.0 μm or less. Is in range.

  In one embodiment, any two of the plurality of first branches, any two of the plurality of second branches, and any of the plurality of third branches. Are adjacent to each other, and any two adjacent ones of the plurality of fourth branch portions are disposed at substantially the same interval.

  In one embodiment, any two of the plurality of first branches, any two of the plurality of second branches, and any of the plurality of third branches. Are adjacent to each other, and any two adjacent intervals among the plurality of fourth branch portions are in the range of 1.4 μm or more and 3.2 μm or less.

  In one embodiment, the first fringe portion is disposed between the trunk portion and the signal line, and the second fringe portion is disposed between the trunk portion and another signal line.

  In one embodiment, the signal line and the other signal line are source bus lines for supplying a voltage to the pixel electrode via a switching element.

  An embodiment includes an alignment layer that is disposed on a surface of each of the first substrate and the second substrate on the liquid crystal layer side and defines an alignment direction of liquid crystal when no voltage is applied, and the alignment layer Includes an orientation regulating layer made of a polymer formed by polymerizing a polymerizable monomer.

  An embodiment includes a pair of polarizing plates having transmission axes orthogonal to each other, wherein the second direction and the third direction are orthogonal to each other, and the direction of the transmission axis of the pair of polarizing plates and the first The two directions differ by 45 degrees, 135 degrees, 225 degrees, or 315 degrees.

  Another liquid crystal display device according to the present invention is a vertical alignment type liquid crystal display device including a plurality of pixels, and supplies a pixel electrode disposed in each of the plurality of pixels and a display signal. A first substrate having a signal line extending in a first direction, a second substrate having a common electrode facing the pixel electrode, and the first substrate and the second substrate. A liquid crystal layer including a liquid crystal having negative dielectric anisotropy, and the pixel electrode has a trunk portion, a first fringe portion, and a second fringe portion, each extending in the first direction, A plurality of first slits extending in a second direction different from the first direction are formed between the trunk portion in the pixel electrode and the first fringe portion, and the trunk portion in the pixel electrode Between the second fringe portion, the first direction and the second It is formed with a plurality of second slits extending in a different third direction and direction.

  In one embodiment, a plurality of third slits extending in the second direction are formed between the trunk portion and the second fringe portion in the pixel electrode, and the trunk portion in the pixel electrode A plurality of fourth slits extending in the third direction are formed between the first fringe portion.

  In one embodiment, the plurality of first slits, the plurality of second slits, the plurality of third slits, and the plurality of fourth slits all have substantially the same width.

  In one embodiment, each width of the plurality of first slits, the plurality of second slits, the plurality of third slits, and the plurality of fourth slits is in a range of 1.4 μm or more and 3.2 μm or less. is there.

  In one embodiment, the plurality of first slits are located between the trunk and the signal line, and the second slit is located between the trunk and another signal line.

  An embodiment includes an alignment layer that is disposed on a surface of each of the first substrate and the second substrate on the liquid crystal layer side and defines an alignment direction of liquid crystal when no voltage is applied, and the alignment layer Includes an orientation regulating layer made of a polymer formed by polymerizing a polymerizable monomer.

  An embodiment includes a pair of polarizing plates having transmission axes orthogonal to each other, wherein the second direction and the third direction are orthogonal to each other, and the direction of the transmission axes of the pair of polarizing plates The second direction is different from 45 degrees, 135 degrees, 225 degrees, or 315 degrees.

  Since the liquid crystal display device of the present invention has the pixel electrode having the above-described shape, liquid crystal alignment anomalies and fluctuations in the periphery of the pixel can be suppressed, and the liquid crystal alignment direction can be stabilized accurately in each pixel. . Therefore, according to the present invention, it is possible to obtain a high-quality display with high luminance in which a decrease in transmittance is prevented in each pixel.

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

  FIG. 1 is a plan view schematically showing the structure of one pixel 10 of a liquid crystal display device 1 according to an embodiment of the present invention, and FIG. 2 is along the line AA ′ in FIG. It is a typical sectional view.

  The liquid crystal display device 1 is a vertical alignment type liquid crystal display device having a plurality of pixels 10 having the configuration shown in FIG. 1 and performing display in a normally black mode by the pixels 10 arranged in a matrix. As shown in FIG. 2, the liquid crystal display device 1 includes a TFT substrate 20 that is an active matrix substrate, a counter substrate 40 that is a color filter substrate, and a liquid crystal layer 50 provided between these substrates. ing. The liquid crystal layer 50 includes nematic liquid crystal having negative dielectric anisotropy (Δε <0).

  A polarizing plate 60 a is provided outside the TFT substrate 20 (opposite the liquid crystal layer 50), and a polarizing plate 60 b is provided outside the counter substrate 40. The polarizing plates 60a and 60b are arranged in crossed Nicols, and one light transmission axis (also simply referred to as a transmission axis) extends in the horizontal direction in FIG. 1, and the other light transmission axis extends in the vertical direction. In the following description, the azimuth direction from the left side to the right side in FIG. 1 is defined as the azimuth direction of 0 °, and the azimuth angle is set counterclockwise with reference to this.

  As shown in FIGS. 1 and 2, the TFT substrate 20 includes a glass substrate (transparent substrate) 21, a scanning line (gate bus line) 22 and a signal line (data bus line) 23a formed on the glass substrate 21. And 23b, an auxiliary capacitance line (Cs line) 24, an insulating layer 25 formed on these wirings, and a pixel electrode 30 and an alignment film 32 formed on the insulating layer 25.

  Each pixel 10 is surrounded by two adjacent scanning lines 22 and signal lines 23 a and 23 b, and a TFT 35 for switching a display voltage to the pixel electrode 30 is arranged for each pixel 10. The gate electrode of the TFT 35 is electrically connected to the scanning line 22, the source electrode is electrically connected to the signal line 23 a via the contact hole 26, and the drain electrode is electrically connected to the pixel electrode 30. An auxiliary capacitance electrode 36 electrically connected to the auxiliary capacitance line 24 through the lead-in line 24 ′ of the auxiliary capacitance line 24 and the contact hole 27 is formed below the pixel electrode 30 at the upper center of the pixel 10. .

  The counter substrate 40 includes a transparent substrate 41, a CF (color filter) layer 42 disposed on the transparent substrate 41 (on the liquid crystal layer side surface), a common electrode 43 formed on the CF layer 42, And an alignment film 44 formed on the common electrode 43.

  Both the alignment film 32 of the TFT substrate 20 and the alignment film 44 of the counter substrate 40 are composed of an alignment layer and an alignment maintaining layer. The alignment layer is a vertical alignment film applied on the substrate, and the alignment maintaining layer is a state in which a voltage is applied to the liquid crystal layer 50 after forming a liquid crystal cell with a photopolymerizable monomer previously mixed in a liquid crystal material. It is formed by photopolymerization with. During the polymerization of the monomer, a voltage is applied to the liquid crystal layer 50 by the pixel electrode 30 and the counter electrode 43, the liquid crystal molecules are aligned by an oblique electric field generated according to the shape of the pixel electrode 30, and light is irradiated in that state to irradiate the monomer. Is polymerized.

  The alignment maintaining layer formed in this way can maintain (store) the alignment (pretilt azimuth) in the liquid crystal molecules even after the voltage is removed (a state where no voltage is applied). The technique for forming such an alignment film is called a polymer alignment alignment (PSA) technique, and details thereof are described in Patent Document 3. This specification uses these patent documents, and detailed description of the alignment maintaining layer is omitted here.

  As shown in FIG. 1, the pixel electrode 30 includes a trunk portion 30a extending in the azimuth angle 0 ° -180 ° direction, a trunk portion 30b extending in the azimuth angle 90 ° -270 ° direction, and an azimuth angle 45 ° -225 ° direction (first order). A plurality of branches 30 c (first branch) extending in one direction), a plurality of branches 30 d (second branch) extending in the azimuth 135 ° -315 ° direction (second direction), and the pixel electrode 30. And a fringe portion 30e which is a peripheral portion.

  The trunk portion 30a includes a trunk portion 30aa extending in the direction of azimuth angle 0 ° from the intersection between the trunk portion 30a and the trunk portion 30b located near the center of the pixel 10, and a trunk portion 30ab extending in the direction of azimuth angle 180 °. The trunk portion 30ba extends in the azimuth angle 90 ° direction and the trunk portion 30bb extends in the azimuth angle 270 ° direction.

  The branch part 30c includes a plurality of branch parts 30ca extending from the trunk part 30aa or 30ba in the azimuth angle 45 ° direction and a plurality of branch parts 30cb extending from the trunk part 30ab or 30bb in the azimuth angle 225 ° direction. It consists of a plurality of branch portions 30da extending from 30ab or 30ba in the direction of azimuth angle 135 ° and a plurality of branch portions 30db extending from the trunk portion 30aa or 30bb in the direction of azimuth angle 315 °.

  The fringe portion 30e includes a fringe portion 30ea including a side on the signal line 23a side of the pixel 30 and extending in a 90 ° -270 ° direction, a fringe portion 30eb including a side on the scanning line 22 side and extending in a 0 ° -180 ° direction, It includes a fringe portion 30ec including a side on the signal line 23b side and extending in a 90 ° -270 ° direction, and a fringe portion 30ed including a lower side and extending in a 0 ° -180 ° direction. The fringe portion 30ea is disposed between the trunk portion 30b and the signal line 23a, and the fringe portion 30ec is disposed between the trunk portion 30b and the signal line 23b.

  Since the pixel electrode 30 has such a shape, a plurality of slits (portions where no electrode material is present) 30 s are formed in the pixel electrode 30. The plurality of slits 30s includes a plurality of slits 30sa, a trunk 30ab, a fringe 30eb, a fringe 30ec, and a trunk 30ab surrounded by the trunk 30aa, the fringe 30ea, the fringe 30eb, and the azimuth angle 45 °. A plurality of slits 30 sb surrounded by the azimuth angle 135 ° direction, a trunk portion 30ab, a fringe portion 30ec, a fringe portion 30ed, a plurality of slits 30sc surrounded by the trunk portion 30bb and extending in the azimuth angle 225 ° direction, and the trunk portion 30bb. It consists of a plurality of slits 30sd that are surrounded by the fringe portion 30ed, the fringe portion 30ea, and the trunk portion 30aa and extend in the direction of the azimuth angle 315 °.

  The widths of the branch portions 30c and 30d are substantially the same, and the widths S of the slits s (the interval between any two adjacent branch portions 30c or 30d) S are substantially the same. As shown in FIG. 1, the width L of the branch portions 30c and 30d means the width in the direction perpendicular to the extending direction of the branch portions, and the width S of the slit s is the slit s or two adjacent branch portions. It means the width in the direction perpendicular to the direction in which c or d extends. The width L may be referred to as a line width L, and the width S may be referred to as a slit width S.

  When the width L or the width S is extremely large or extremely small, the alignment regulating force does not work properly and abnormal alignment of liquid crystal molecules occurs, so the width L is in the range of 1.4 μm or more and 8.0 μm or less. The width S is preferably in the range of 1.4 μm to 3.2 μm.

  The pixel electrode 30 having the above-described shape and the alignment films 32 and 44 form a multi-domain having a 4D structure in one pixel 10. When no voltage is applied, the pretilt azimuths of the liquid crystal molecules in the four domains show azimuths parallel to the branch portions 30ca, 30da, 30cb, and 30db, respectively, according to the orientations stored in the alignment films 32 and 44. When a voltage is applied, the liquid crystal molecules of the four domains are oriented in a polar angle direction that is parallel to the branches 30ca, 30da, 30cb, and 30db (director direction of the domain) and is parallel to the substrate surface. At this time, since the orientation azimuth coincides with the pretilt azimuth, orientation in an accurate azimuth with an extremely fast response speed is realized.

  FIG. 3 is a plan view schematically showing a part of the pixel electrode 30 in order to explain the effect obtained by the liquid crystal display device 1.

  As shown in FIG. 3, the ends of the plurality of branch portions 30ca and 30cb of the pixel electrode 30 are all connected to the fringe portion 30e without interruption. In other words, the slits 30s formed between any two of the plurality of branches 30ca or 30cb and between any two of the plurality of branches 30da or 30db are all surrounded by a pixel electrode member. It is an enclosed slit.

  Due to the presence of the fringe portion 30e of the pixel electrode 30, the electric field due to the signal line 23a (and 23b) and the electric field due to the fringe portion 30ea (and 30ec) cancel each other, and the liquid crystal molecules on the slit 30s, particularly the signal line 23a (and The electrical influence from the signal line 23a (and 23b) on the liquid crystal molecules at a position close to 23b) is blocked (see the broken line arrow in FIG. 3).

  Therefore, almost all of the liquid crystal molecules on the slit 30s are ideally aligned in parallel to the azimuth direction in which the slit 30s extends in accordance with the electric field applied by the pixel electrode 30, and the liquid crystal molecules in a state where no voltage is applied. In addition, since it is not affected by the signal line 23a (and 23b), it shows a desired pretilt azimuth parallel to the azimuth direction in which the slit 30s extends. In this way, all the liquid crystal molecules can be accurately aligned in the desired alignment direction, and fluctuations in the liquid crystal alignment direction are less likely to occur, resulting in problems such as a decrease in transmittance, display unevenness, or abnormal gradation. Is prevented.

  FIG. 4 is a diagram for explaining the effect obtained by the pixel electrode 30 of the liquid crystal display device 1. FIG. 4A is a diagram showing a white display state by the pixel electrode 30, and FIG. ) Is a diagram showing a white display state by the conventional pixel electrode shown in FIG.

  As shown in portions B and B ′ in FIG. 4A, according to the pixel electrode 30 of the liquid crystal display device 1, the transmittance is not lowered even in the peripheral portion of the pixel, which is the same as that in the central portion of the pixel. High brightness is obtained. On the other hand, according to a conventional pixel electrode that does not include a fringe portion, as shown by C and C ′ in FIG. 4B, the transmittance is reduced in the peripheral portion of the pixel, and the dark portion occupies in the pixel. The area is relatively wide and high brightness is not obtained.

  As described above, according to the pixel electrode 30 of the present invention, a high transmittance can be obtained even in the peripheral portion of the pixel, so that the area contributing to white display in the pixel can be widened and a high luminance is achieved. Quality display is possible.

  The present invention can be used to improve the display characteristics of a liquid crystal display device, and is particularly suitable for a liquid crystal display device having a relatively small pixel pitch such as a liquid crystal display device for a mobile phone.

It is a top view which shows typically the structure of one pixel in the liquid crystal display device 1 of embodiment by this invention. FIG. 2 is a schematic cross-sectional view of the liquid crystal display device 1 taken along the line A-A ′ in FIG. 1. FIG. 5 is a diagram for explaining an effect obtained by the pixel electrode 30 of the liquid crystal display device 1 and a plan view for explaining an alignment state of liquid crystal in the vicinity of the pixel electrode 30. 4A and 4B are diagrams for explaining an effect obtained by the pixel electrode 30 of the liquid crystal display device 1, FIG. 5A is a diagram showing a display state by the pixel electrode 30, and FIG. 5B is a conventional liquid crystal display shown in FIG. It is a figure showing the display state by an apparatus. It is a figure for demonstrating the influence of the signal line with respect to the liquid crystal near the pixel electrode of the conventional liquid crystal display device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 10, 10 'Pixel 20 TFT substrate 21 Glass substrate 22 Scan line 23a, 23b Signal line 24 Auxiliary capacity line 24' Lead-in line 25 Insulating layer 26, 27 Contact hole 30 Pixel electrode 30a, 30b, 30aa, 30ab, 30ba, 30bb Stem 30c, 30d, 30ca, 30cb, 30da, 30db, Branch 30e, 30ea, 30eb, 30ec, 30ed Fringe 30s, 30sa, 30sb, 30sc, 30sd Slit 32 Alignment film 35 TFT
36 Auxiliary Capacitance Electrode 40 Counter Substrate 41 Transparent Substrate 42 CF Layer 43 Common Electrode 44 Alignment Film 50 Liquid Crystal Layer 60a, 60b Polarizer 90 Pixel Electrode 90a, 90b Trunk 90c, 90d Branch

Claims (17)

  1. A vertical alignment type liquid crystal display device having a plurality of pixels,
    A first substrate including a pixel electrode disposed in each of the plurality of pixels and a signal line extending in a first direction for supplying a display signal;
    A second substrate having a common electrode facing the pixel electrode;
    A liquid crystal layer including a liquid crystal having a negative dielectric anisotropy disposed between the first substrate and the second substrate,
    The pixel electrode has a trunk portion, a first fringe portion, and a second fringe portion, each extending in the first direction, and a second direction different from the first direction between the trunk portion and the first fringe portion. A liquid crystal display comprising: a plurality of first branch portions extending; and a plurality of second branch portions extending in a third direction different from the first direction and the second direction between the trunk portion and the second fringe portion. apparatus.
  2.   A plurality of third branch portions extending in the second direction between the trunk portion and the second fringe portion; and a plurality of pixel electrodes extending in the third direction between the trunk portion and the first fringe portion. The liquid crystal display device according to claim 1, further comprising: a fourth branch portion.
  3.   The liquid crystal display according to claim 2, wherein the plurality of first branch portions, the plurality of second branch portions, the plurality of third branch portions, and the plurality of fourth branch portions have substantially the same width. apparatus.
  4.   The widths of the plurality of first branch portions, the plurality of second branch portions, the plurality of third branch portions, and the plurality of fourth branch portions are in the range of 1.4 μm or more and 8.0 μm or less. Item 4. The liquid crystal display device according to Item 2 or 3.
  5.   Arbitrarily adjacent two of the plurality of first branch portions, Arbitrary adjacent two of the plurality of second branch portions, Arbitrary adjacent two of the plurality of third branch portions 5. The liquid crystal display device according to claim 2, wherein any two adjacent ones of the plurality of fourth branch portions are disposed at substantially the same interval. 5.
  6.   Arbitrarily adjacent two of the plurality of first branch portions, Arbitrary adjacent two of the plurality of second branch portions, Arbitrary adjacent two of the plurality of third branch portions 6. The liquid crystal display device according to claim 2, wherein an interval between any two of the plurality of fourth branch portions is in a range of 1.4 μm or more and 3.2 μm or less. .
  7.   The first fringe portion is disposed between the trunk portion and the signal line, and the second fringe portion is disposed between the trunk portion and another signal line. 2. A liquid crystal display device according to item 1.
  8.   8. The liquid crystal display device according to claim 1, wherein the signal line and the other signal line are source bus lines for supplying a voltage to the pixel electrode through a switching element. 9.
  9. An alignment layer that is disposed on the liquid crystal layer side surface of each of the first substrate and the second substrate and that defines the alignment direction of the liquid crystal when no voltage is applied;
    The liquid crystal display device according to any one of claims 1 to 8, wherein the alignment layer includes an alignment regulating layer made of a polymer formed by polymerizing a polymerizable monomer.
  10. It has a pair of polarizing plates with transmission axes orthogonal to each other,
    The second direction and the third direction are orthogonal to each other;
    10. The liquid crystal display device according to claim 1, wherein a direction of a transmission axis of the pair of polarizing plates is different from the second direction by 45 degrees, 135 degrees, 225 degrees, or 315 degrees. .
  11. A vertical alignment type liquid crystal display device having a plurality of pixels,
    A first substrate including a pixel electrode disposed in each of the plurality of pixels and a signal line extending in a first direction for supplying a display signal;
    A second substrate having a common electrode facing the pixel electrode;
    A liquid crystal layer including a liquid crystal having a negative dielectric anisotropy disposed between the first substrate and the second substrate,
    The pixel electrode has a trunk portion, a first fringe portion, and a second fringe portion, each extending in the first direction.
    A plurality of first slits extending in a second direction different from the first direction are formed between the trunk portion and the first fringe portion in the pixel electrode,
    A plurality of second slits extending in a third direction different from the first direction and the second direction are formed between the trunk portion and the second fringe portion in the pixel electrode. .
  12. A plurality of third slits extending in the second direction are formed between the trunk portion and the second fringe portion in the pixel electrode,
    The liquid crystal display device according to claim 11, wherein a plurality of fourth slits extending in the third direction are formed between the trunk portion and the first fringe portion in the pixel electrode.
  13.   The liquid crystal display device according to claim 12, wherein the plurality of first slits, the plurality of second slits, the plurality of third slits, and the plurality of fourth slits all have substantially the same width.
  14.   The widths of the plurality of first slits, the plurality of second slits, the plurality of third slits, and the plurality of fourth slits are in the range of 1.4 μm or more and 3.2 μm or less. Or the liquid crystal display device of 13.
  15.   The plurality of first slits are located between the trunk and the signal line, and the second slit is located between the trunk and another signal line. The liquid crystal display device described.
  16. An alignment layer that is disposed on the liquid crystal layer side surface of each of the first substrate and the second substrate and that defines the alignment direction of the liquid crystal when no voltage is applied;
    The liquid crystal display device according to claim 11, wherein the alignment layer includes an alignment regulating layer made of a polymer formed by polymerizing a polymerizable monomer.
  17. It has a pair of polarizing plates with transmission axes orthogonal to each other,
    The second direction and the third direction are orthogonal to each other;
    17. The liquid crystal display device according to claim 11, wherein a direction of a transmission axis of the pair of polarizing plates is different from the second direction by 45 degrees, 135 degrees, 225 degrees, or 315 degrees. .
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