KR20080077468A - Liquid crystal composition and liquid crystal display comprising the same - Google Patents

Abstract

A liquid crystal composition is provided to enhance an opening rate of a liquid crystal display device while reinforcing voltage holding performance by increasing liquid crystal electricity storage capacity and reducing auxiliary electricity storage capacity. A vertical alignment type liquid crystal composition includes 10-25wt% of a first liquid crystal group comprising a neutral liquid crystal compound, 3-15wt% of a second liquid crystal group comprising a liquid crystal compound having positive dielectric anisotropy, and 60-80wt% of a third liquid crystal group comprising a liquid crystal compound having negative dielectric anisotropy. A liquid crystal display device comprises: a first substrate; a second substrate which faces the first substrate; a pair of electric field generation electrodes which are formed on at least one substrate of the first and second substrates; a liquid crystal layer intervened between the first and second substrates; and a slope direction decision member which decides a sloping direction of a liquid crystal compound in the liquid crystal layer. The liquid crystal layer contains the liquid crystal composition.

Description

Liquid crystal composition and a liquid crystal display including the same {LIQUID CRYSTAL COMPOSITION AND LIQUID CRYSTAL DISPLAY COMPRISING THE SAME}

1 is a layout view of a thin film transistor array panel for a liquid crystal display according to an exemplary embodiment of the present invention.

2 is a layout view of a common electrode panel for a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 3 is a layout view of a liquid crystal display including the thin film transistor array panel of FIG. 1 and the common electrode panel of FIG. 2.

4 and 5 are cross-sectional views of the liquid crystal display of FIG. 3 taken along lines IV-IV and V-V, respectively.

<Description of Drawing>

3: liquid crystal layer 310: liquid crystal molecules

11, 21: alignment film 12, 22: polarizer

81, 82: contact auxiliary member 83: holding electrode wire connecting leg

91, 92a, 92b, 71, 72a, 72b: incision

100, 200: display panel 110, 210: insulating substrate

121: gate line 124: gate electrode

129: end portion of gate line 131: sustain electrode line

133a-133d: sustain electrode 140: gate insulating film

151 and 154: semiconductors 161, 163 and 165: ohmic contact members

171: data line 173: source electrode

175: drain electrode 179: end of data line

180: protective film 183a, 183b, 185: contact hole

191: pixel electrode

220: light blocking member 230: color filter

250: overcoat 270: common electrode

The present invention relates to a liquid crystal composition and a liquid crystal display including the same.

Liquid crystal displays (LCDs) are one of the most widely used flat panel displays. The liquid crystal display includes two display panels on which an electric field generating electrode is formed and a liquid crystal layer interposed therebetween, and determines a direction of liquid crystal molecules of the liquid crystal layer by generating an electric field in the liquid crystal layer by applying a voltage to the electric field generating electrode. And transmittance of light passing through the liquid crystal layer.

In liquid crystal displays, liquid crystals are very important for controlling a light transmittance to obtain a desired image. The liquid crystal may be divided into a horizontally aligned liquid crystal in which the long axis of the liquid crystal is arranged parallel to the electric field generating direction and the vertically aligned liquid crystal in which the long axis of the liquid crystal is arranged perpendicular to the electric field generating direction.

Horizontally oriented liquid crystals have positive dielectric anisotropy and can be applied to horizontally oriented liquid crystal displays such as torsion nematic (TN) liquid crystal displays, and vertically oriented liquid crystals have negative dielectric anisotropy and have vertical alignment ( vertical aligned (VA) may be applied to a liquid crystal display.

On the other hand, the liquid crystal display device has a capacitor (hereinafter referred to as a 'liquid crystal capacitor') formed between the liquid crystal layer and the field generating electrode, and a separate capacitor (hereinafter referred to as 'maintenance') to secure a voltage holding capability. Storage capacitor).

However, in order to form the storage capacitor, an additional wiring overlapping with the pixel electrode is required, so that the aperture ratio may be lowered.

Therefore, the technical problem to be achieved by the present invention is to solve this problem and to increase the aperture ratio while enhancing the voltage holding capability.

Liquid crystal composition according to an embodiment of the present invention is 10 to 25% by weight of the first liquid crystal group containing a neutral liquid crystal compound, 3 to 15% by weight of the second liquid crystal group containing a liquid crystal compound having positive dielectric anisotropy, and negative 60 to 80 weight% of the 3rd liquid crystal group containing the liquid crystal compound which has dielectric constant anisotropy of is included.

The first liquid crystal group is represented by Formulas (I) to (III):

At least one of the liquid crystal compounds represented by, wherein R _{One To} R _{6 It} may be selected from the same or different from each other alkyl or alkoxy group having 1 to 10 carbon atoms.

The second liquid crystal group is represented by Formulas (IV) to (VIII):

At least one of the liquid crystal compound represented by, wherein R _{7 To} R _{11 It} may be selected from the same or different from each other alkyl or alkoxy group having 1 to 10 carbon atoms.

The third liquid crystal group is represented by Formulas (IX) to (XII):

At least one of the liquid crystal compound represented by, wherein R ₁₂ to R ₁₉ may be selected from the same or different from each other alkyl or alkoxy group having 1 to 10 carbon atoms.

The average dielectric anisotropy (Δε) of the liquid crystal composition may be -2.6 to -3.4.

Ratio (Δε / ε _⊥) of the average dielectric anisotropy (Δε) and the mean dielectric constant (ε _⊥) in the minor axis direction of the liquid crystal compound of the liquid crystal composition can be 0.31 to 0.46 days.

The liquid crystal composition may have a phase transition temperature of 70 to 95 ° C. and a refractive index anisotropy of 0.103 or less.

A liquid crystal display according to an exemplary embodiment of the present invention includes a pair of electric field generating electrodes formed on at least one of a first substrate, a second substrate facing the first substrate, the first substrate, and the second substrate; A first liquid crystal layer interposed between the first substrate and the second substrate, and an inclined direction determining member configured to determine a direction in which the liquid crystal compound of the liquid crystal layer is inclined, wherein the liquid crystal layer includes a neutral liquid crystal compound Liquid crystal group 10 to 25% by weight, the second liquid crystal group 3 to 15% by weight containing a liquid crystal compound having positive dielectric anisotropy, and the third liquid crystal group 60 to 80% by weight comprising a liquid crystal compound having negative dielectric anisotropy It includes a liquid crystal composition comprising%.

The first liquid crystal group may include at least one of the liquid crystal compounds represented by Formulas (I) to (III), and the second liquid crystal group is selected from the liquid crystal compounds represented by Formulas (IV) to (VIII). It may include at least one, and the third liquid crystal group may include at least one of the liquid crystal compounds represented by the formula (IX) to (XII).

The inclination direction determining member may be a cutout formed in the electric field generating electrode or a protrusion formed on the electric field generating electrode.

Hereinafter, a liquid crystal composition according to an embodiment of the present invention will be described.

The liquid crystal composition includes various kinds of liquid crystal compounds having different physical properties.

The liquid crystal compound includes a core group constituting the central axis and a terminal group and / or a lateral group connected thereto.

The central portion may include one or more cyclic compounds selected from phenyl groups, cyclohexyl groups, and heterocycles.

Terminal groups and side chain groups may include an alkyl group, an alkoxy group, a non-polar group such as an alkenyl group or a polar group such as a fluorine atom. The physical properties vary depending on the terminal groups and the side chain groups.

The liquid crystal composition according to the exemplary embodiment of the present invention is a liquid crystal compound having no dielectric anisotropy (hereinafter, referred to as a 'neutral liquid crystal compound') and a liquid crystal compound having a dielectric anisotropy (hereinafter, referred to as a 'polar liquid crystal compound'). crystal compound).

The neutral liquid crystal compound does not exhibit dielectric anisotropy but exhibits refractive index anisotropy and is a component for appropriately maintaining the viscosity of the liquid crystal. The neutral liquid crystal compound may be at least one selected from liquid crystal compounds represented by the following formulas (I), (II) and (III), respectively:

R ₁ to R ₆ may be selected from alkyl groups or alkoxy groups, which may be the same as or different from each other, and each having 1 to 10 carbon atoms.

The neutral liquid crystal compound may be contained in about 10 to 25% by weight based on the total content of the liquid crystal composition. The content range corresponds to the remaining amount range excluding the content of the polar liquid crystal compound described below, and by being contained in the above range, it is possible to appropriately maintain the viscosity of the liquid crystal composition.

The polar liquid crystal compound exhibits dielectric anisotropy (Δε ₁ ) and refractive index anisotropy (Δn ₁ ) and has at least one fluorine atom (F) in the side chain group.

Dielectric anisotropy (Δε ₁₎ is the difference of the vertical dielectric constant (ε _⊥1) of the vertical and horizontal dielectric constant of the parallel to the major axis direction of the liquid crystal compound (ε _∥1) and the major axis direction, the horizontal dielectric constant (ε _{When ∥1} is larger, positive permittivity anisotropy is shown, and when the vertical permittivity _ε1 is larger, negative permittivity anisotropy is shown.

The liquid crystal compounds having positive dielectric anisotropy are arranged almost parallel to the direction of electric field generation when the electric field is applied, and the liquid crystal compounds having negative dielectric anisotropy are arranged almost perpendicular to the direction of electric field generation when the electric field is applied. Therefore, in general, a liquid crystal compound having a positive dielectric anisotropy is applied to a horizontally aligned liquid crystal display device, and a liquid crystal compound having a negative dielectric anisotropy is applied to a vertically aligned liquid crystal display device.

The liquid crystal composition according to the exemplary embodiment of the present invention is applied to a vertically aligned liquid crystal display and includes both a liquid crystal compound having positive dielectric anisotropy and a liquid crystal compound having negative dielectric anisotropy.

The liquid crystal compound having positive dielectric anisotropy may be at least one selected from liquid crystal compounds represented by the following general formulas (IV) to (VIII):

Wherein R ₇ to R ₁₁ are the same or different from each other and are selected from alkyl or alkoxy groups each having 1 to 10 carbon atoms.

The liquid crystal compound having positive dielectric anisotropy may be contained in an amount of about 3 to 15 wt% based on the total content of the liquid crystal composition.

The liquid crystal compound having negative dielectric anisotropy may be at least one selected from liquid crystal compounds represented by formulas (IX) to (XII), respectively:

Wherein R ₁₂ to R ₁₉ may be selected from an alkyl group or an alkoxy group, the same as or different from each other, each having 1 to 10 carbon atoms.

The liquid crystal compound having negative dielectric anisotropy may be contained in an amount of about 60 to 80 wt% based on the total content of the liquid crystal composition.

Since the above-described liquid crystal composition is applied to a vertically aligned liquid crystal display device, the average dielectric anisotropy Δε has a negative value.

As described above, the liquid crystal composition according to one embodiment of the present invention increases the content of the liquid crystal compound having negative dielectric anisotropy to about 60 to 80% by weight. As such, by increasing the content of the liquid crystal compound having negative dielectric anisotropy to about 60% by weight or more, the value of the vertical dielectric constant (ε _⊥ ) of the liquid crystal composition is increased, and preferably has a vertical dielectric constant value of about 6.7 or more. However, when contained in more than 80% by weight, not only the reliability of the liquid crystal composition is lowered, but also the content of the neutral liquid crystal compound can be relatively reduced, thereby increasing the viscosity.

In addition, the liquid crystal composition according to the exemplary embodiment of the present invention contains about 3 to 15 wt% of the liquid crystal compound having positive dielectric anisotropy despite being applied to a vertically aligned liquid crystal display device. With such a liquid crystal compound having a positive dielectric anisotropy at least about 3% by weight also increases in the horizontal dielectric constant (ε _∥) of the liquid crystal composition. However, when the liquid crystal compound having positive dielectric anisotropy is contained in an amount greater than about 15% by weight, the movement of the liquid crystal compound may be slowed and the driving voltage may be increased.

 Accordingly, the total dielectric constant of the liquid crystal composition in consideration of the vertical dielectric constant and the horizontal dielectric constant increases, and when applied to the liquid crystal display device, the liquid crystal storage capacitance formed between the field generating electrode and the liquid crystal layer may be increased, thereby enhancing the voltage holding capability. Therefore, it is not necessary to separately form an auxiliary holding capacitor that assists the liquid crystal capacitance, or the area thereof can be reduced, thereby increasing the aperture ratio of the liquid crystal display device. In addition, when the liquid crystal capacitance is increased, the kickback voltage decreases to reduce flicker and The same display defect can be reduced.

On the other hand, since the liquid crystal composition contains a liquid crystal compound having positive dielectric anisotropy, the average dielectric anisotropy (Δε) of the liquid crystal composition is lowered to about -2.6 to -3.4.

As such, the average dielectric anisotropy (Δε) of the liquid crystal composition is lowered and the value of the vertical dielectric constant (ε _증가 ) is increased, so that the ratio (Δε / ε _⊥ ) of the average dielectric constant anisotropy (Δε) and the vertical dielectric constant (ε _⊥ ) of the liquid crystal composition is It is significantly lowered and is preferably in the range of about 0.31 to 0.46.

The liquid crystal composition described above also has a phase transition temperature (T _ni ) of about 70 to 95 ° C. and a refractive index anisotropy (Δn) of about 0.103 or less.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle. Next, a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5.

1 is a layout view of a thin film transistor array panel for a liquid crystal display according to an exemplary embodiment of the present invention, FIG. 2 is a layout view of a common electrode display panel for a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. FIG. 4 is a layout view of a liquid crystal display including the thin film transistor array panel and the common electrode display panel of FIG. 2, and FIGS. 4 and 5 are cross-sectional views of the liquid crystal display of FIG. 3 taken along lines IV-IV and VV, respectively.

1 to 5, a liquid crystal display according to an exemplary embodiment of the present invention includes a thin film transistor array panel 100 and a common electrode panel 200 facing each other and between the two display panels 100 and 200. The liquid crystal layer 3 is included.

First, the thin film transistor array panel 100 will be described with reference to FIGS. 1, 3, 4, and 5.

A plurality of gate lines 121 and a plurality of storage electrode lines 131 are formed on an insulating substrate 110 made of transparent glass or plastic.

The gate line 121 transmits a gate signal and mainly extends in a horizontal direction. Each gate line 121 includes a plurality of gate electrodes 124 protruding upwards and a wide end portion 129 for connection with another layer or an external driving circuit.

The storage electrode line 131 receives a predetermined voltage and has a stem line extending substantially in parallel with the gate line 121 and a plurality of first, second, third and fourth storage electrodes 133a, 133b, 133c, 133d) a set and a plurality of connections 133e.

The first and second storage electrodes 133a and 133b extend in the vertical direction and face each other. The first storage electrode 133a has a fixed end connected to the stem line and a free end opposite thereto, and the free end includes a protrusion. The third and fourth storage electrodes 133c and 133d extend obliquely from the center of the first storage electrode 133a to the lower end and the upper end of the second storage electrode 133b. The connecting portion 133e is connected between adjacent sets of sustain electrodes 133a to 133d. However, the shape and arrangement of the storage electrode line 131 may be modified in various ways, and the storage electrode line 131 may be omitted when only the liquid crystal storage capacity is sufficient.

The gate line 121 and the storage electrode line 131 include an aluminum (Al) metal, a silver (Ag) metal, a copper (Cu) metal, a molybdenum metal, chromium (Cr), tantalum (Ta), and titanium (Ti). It can be made of low resistance conductors. However, they may have a multilayer structure including two conductive films (not shown) having different physical properties.

Side surfaces of the gate line 121 and the storage electrode line 131 are inclined with respect to the surface of the substrate 110, and the inclination angle is preferably about 30 ° to about 80 °.

A gate insulating layer 140 made of silicon nitride (SiNx) or silicon oxide (SiOx) is formed on the gate line 121 and the storage electrode line 131.

A plurality of linear semiconductors 151 made of hydrogenated amorphous silicon (hereinafter referred to as a-Si) or polysilicon are formed on the gate insulating layer 140. The linear semiconductor 151 mainly extends in the longitudinal direction and includes a plurality of projections 154 extending toward the gate electrode 124.

A plurality of linear and island ohmic contacts 161 and 165 are formed on the semiconductor 151. The ohmic contacts 161 and 165 may be made of a material such as n + hydrogenated amorphous silicon in which n-type impurities such as phosphorus are heavily doped, or may be made of silicide. The linear ohmic contact 161 has a plurality of protrusions 163, and the protrusion 163 and the island-type ohmic contact 165 are paired and disposed on the protrusion 154 of the semiconductor 151.

Side surfaces of the semiconductor 151 and the ohmic contacts 161 and 165 are also inclined with respect to the surface of the substrate 110, and the inclination angle is about 30 ° to 80 °.

On the ohmic contacts 161 and 165 and the gate insulating layer 140, a plurality of data lines 171, a plurality of drain electrodes 175, and a plurality of isolated metal pieces ( 178 is formed.

The data line 171 transmits a data signal and mainly extends in a vertical direction to intersect the gate line 121, the stem line of the storage electrode line 131, and the connecting portion 133e. Each data line 171 includes a wide end portion 179 for connecting a plurality of source electrodes 173 extending toward the gate electrode 124 with another layer or an external driving circuit.

The drain electrode 175 is separated from the data line 171 and faces the source electrode 173 around the gate electrode 124. Each drain electrode 175 has one wide end and the other end having a rod shape, and the rod end portion is partially surrounded by the source electrode 173.

One gate electrode 124, one source electrode 173, and one drain electrode 175 together with the protrusion 154 of the semiconductor 151 form one thin film transistor (TFT). A channel of the transistor is formed in the protrusion 154 between the source electrode 173 and the drain electrode 175.

The isolated metal piece 178 is positioned on the gate line 121 near the first storage electrode 133a.

The data line 171, the drain electrode 175, and the isolated metal piece 178 may be made of a low resistance conductor like the gate line 121.

The data line 171, the drain electrode 175, and the isolated metal piece 178 may also be inclined at an inclination angle of about 30 ° to about 80 ° with respect to the surface of the substrate 110.

The ohmic contacts 161 and 165 exist only between the semiconductor 151 below and the data line 171 and the drain electrode 175 thereon, and lower the contact resistance therebetween.

A passivation layer 180 is formed on the data line 171, the drain electrode 175, the isolated metal piece 178, and the exposed semiconductor 151.

A plurality of pixel electrodes 191, a plurality of overpasses 83, and a plurality of contact assistants 81 and 82 are formed on the passivation layer 180. They may be made of a transparent conductive material such as ITO or IZO or a reflective metal such as aluminum, silver, chromium or an alloy thereof.

The pixel electrode 191 is physically and electrically connected to the drain electrode 175 through the contact hole 185 and receives a data voltage from the drain electrode 175. The pixel electrode 191 to which the data voltage is applied is generated between the two electrodes 191 and 270 by generating an electric field together with the common electrode 270 of the other display panel 200 to which the common voltage is applied. The direction of the liquid crystal molecules of the liquid crystal layer 3 is determined. The polarization of light passing through the liquid crystal layer 3 varies according to the direction of the liquid crystal molecules determined as described above.

The pixel electrode 191 and the common electrode 270 form a liquid crystal capacitor to maintain an applied voltage even after the thin film transistor is turned off.

The pixel electrode 191 overlaps the storage electrode lines 131 including the storage electrodes 133a-133d to form a storage capacitor and enhances the voltage holding capability of the liquid crystal capacitor.

Each pixel electrode 191 has four peripheral sides substantially parallel to the gate line 121 or the data line 171 and has a substantially rectangular shape in which four corners are chamfered. The hypotenuse of the pixel electrode 191 forms an angle of about 45 degrees with respect to the gate line 121. A central cutout 91, a lower cutout 92a, and an upper cutout 92b are formed in the pixel electrode 191, and the pixel electrode 191 includes a plurality of regions by the cutouts 91-92b. It is divided into partitions. The cutouts 91-92b are almost inverted symmetric with respect to an imaginary transverse centerline that bisects the pixel electrode 191.

The lower and upper cutouts 92a and 92b extend obliquely from the right side to the left side of the pixel electrode 191 and overlap the third and fourth sustain electrodes 133c and 133d, respectively. The lower and upper cutouts 92a and 92b are positioned at the lower half and the upper half with respect to the horizontal center line of the pixel electrode 191, respectively. The lower and upper cutouts 92a and 92b extend perpendicular to each other at an angle of about 45 degrees with respect to the gate line 121.

The central cutout 91 extends along the horizontal centerline of the pixel electrode 191 and has an inlet at the right side thereof. The inlet of the central incision 91 has a pair of hypotenuses substantially parallel to the lower incision 92a and the upper incision 92b, respectively. The central cutout 91 includes a horizontal portion and a pair of diagonal lines connected thereto. The horizontal portion extends shortly along the horizontal center line of the pixel electrode 191, and the pair of diagonal portions substantially extends toward the right side of the pixel electrode 191 from the horizontal portion with the lower cutout 92a and the upper cutout 92b, respectively. Stretched side by side.

Accordingly, the lower half of the pixel electrode 191 is divided into two regions by the lower cutout 92a, and the upper half is also divided into two regions by the upper cutout 92b. In this case, the number of regions or the number of cutouts may vary depending on design factors such as the size of the pixel electrode 191, the ratio of the lengths of the horizontal and vertical sides of the pixel electrode 191, the type and characteristics of the liquid crystal layer 3, and the like. .

The connecting leg 83 crosses the gate line 121 and exposes the first portion of the storage electrode line 131 and the first holding portion through the contact holes 183a and 183b positioned opposite to each other with the gate line 121 interposed therebetween. The electrode 133a is connected to the exposed end of the free end. The storage electrode lines 131 including the storage electrodes 133a and 133b may be used together with the connection legs 83 to repair defects in the gate line 121, the data line 171, or the thin film transistor.

The contact auxiliary members 81 and 82 are connected to the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 through the contact holes 181 and 182, respectively. The contact auxiliary members 81 and 82 compensate for and protect the adhesion between the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 and the external device.

Next, the common electrode display panel 200 will be described with reference to FIGS. 2 to 4.

A light blocking member 220 is formed on an insulating substrate 210 made of transparent glass, plastic, or the like. The light blocking member 220 is called a black matrix and blocks light leakage between the pixel electrodes 191. The light blocking member 220 has a plurality of openings 225 facing the pixel electrode 191 and having substantially the same shape as the pixel electrode 191. However, the light blocking member 220 may include a portion corresponding to the gate line 121 and the data line 171 and a portion corresponding to the thin film transistor.

A plurality of color filters 230 is also formed on the substrate 210. The color filter 230 is mostly present in an area surrounded by the light blocking member 230, and may extend in the vertical direction along the column of the pixel electrodes 191. Each color filter 230 may display one of three primary colors such as red, green, and blue.

An overcoat 250 is formed on the color filter 230 and the light blocking member 220. The overcoat 250 may be made of an (organic) insulator, which prevents the color filter 230 from being exposed and provides a flat surface. The overcoat 250 may be omitted.

The common electrode 270 is formed on the overcoat 250. The common electrode 270 is made of a transparent conductor such as ITO or IZO, and the plurality of cutouts 71, 72a, and 72b are formed on the common electrode 270.

One set of cutouts 71-72b faces one pixel electrode 191 and includes a central cutout 71, a lower cutout 72a, and an upper cutout 72b. Each of the cutouts 71-72b is disposed between adjacent cutouts 91-92b of the pixel electrode 191 or between cutouts 92a and 92b and the hypotenuse of the pixel electrode 191. In addition, each cutout 71-72b includes at least one diagonal line extending substantially in parallel with the lower cutout 92a or the upper cutout 92b of the pixel electrode 191. The cutouts 71-72b are almost inverted symmetric with respect to the horizontal center line of the pixel electrode 191.

The lower and upper cutouts 72a and 72b respectively include an oblique section, a horizontal section and a vertical section. The diagonal portion extends from the upper side or the lower side of the pixel electrode 191 to the left side. The horizontal part and the vertical part extend from each end of the oblique part along the sides of the pixel electrode 191 while overlapping the sides and form an obtuse angle with the oblique part.

The central cutout 71 includes a central transverse portion, a pair of oblique portions and a pair of longitudinal longitudinal portions. The central horizontal portion extends from the left side of the pixel electrode 191 to the right along the horizontal center line of the pixel electrode 191. The pair of oblique portions extends in parallel with the lower and upper cutouts 72a and 72b while forming an obtuse angle with the central horizontal portion from the end of the central horizontal portion toward the right side of the pixel electrode 191. The vertical longitudinal portion extends along the right side of the pixel electrode 191 from the end of the diagonal line and overlaps the right side, and forms an obtuse angle with the diagonal line.

The number of the cutouts 71-72b may also vary according to design factors, and the light blocking member 220 may overlap the cutouts 71-72b to block light leakage near the cutouts 71-72b.

When a common voltage is applied to the common electrode 270 and a data voltage is applied to the pixel electrode 191, an electric field almost perpendicular to the surfaces of the display panels 100 and 200 is generated. In response to the electric field, the liquid crystal molecules attempt to change their long axis to be perpendicular to the direction of the electric field.

The cutouts 71-72b and 91-92b of the field generating electrodes 191 and 270 and the sides of the pixel electrode 191 distort the electric field to create horizontal components that determine the inclination direction of the liquid crystal molecules. The horizontal component of the electric field is substantially perpendicular to the sides of the cutouts 71-72b and 91-92b and the sides of the pixel electrode 191.

Referring to FIG. 3, one set of cutouts 71-72b and 91-92b divides the pixel electrode 191 into a plurality of sub-areas, and each sub-region is a main portion of the pixel electrode 191. It has two primary edges that form a side and an oblique angle. The periphery of each subregion forms about 45 degrees with the polarization axis of the polarizers 12 and 22, in order to maximize the light efficiency.

Most of the liquid crystal molecules on each subregion are inclined in a direction perpendicular to the periphery thereof, and thus, the inclination directions are approximately four directions. As described above, when the liquid crystal molecules are inclined in various directions, the reference viewing angle of the liquid crystal display is increased.

The shape and arrangement of the cutouts 71-72b and 91-92b can be variously modified.

At least one cutout 71-72b, 91-92b may be replaced by a protrusion (not shown) or depression (not shown). The protrusions may be made of organic or inorganic materials and may be disposed above or below the field generating electrodes 191 and 270.

Alignment layers 11 and 21 are coated on inner surfaces of the display panels 100 and 200, and they may be vertical alignment layers.

The liquid crystal display according to the exemplary embodiment of the present invention may further include a phase retardation film (not shown) for compensating for the delay of the liquid crystal layer 3.

In the liquid crystal layer 3, the average dielectric anisotropy has negative dielectric anisotropy, and the liquid crystal molecules 310 of the liquid crystal layer 3 have their long axes substantially perpendicular to the surfaces of the two display panels 100 and 200 in the absence of an electric field. Is oriented to achieve. Therefore, incident light does not pass through the quadrature polarizers 12 and 22 and is blocked.

The liquid crystal layer 3 is composed of a liquid crystal composition comprising all of a neutral liquid crystal compound, a liquid crystal compound having positive dielectric anisotropy and a liquid crystal compound having negative dielectric anisotropy, and the neutral liquid crystal compound is about 10 to the total content of the liquid crystal composition. 25 wt% to 25 wt%, the liquid crystal compound having positive dielectric anisotropy may be contained in an amount of about 3 to 15 wt% and a liquid crystal compound having negative dielectric anisotropy in an amount of about 60 to 80 wt%.

, The average dielectric anisotropy (Δε) of the liquid crystal composition as described above is about -2.6 to -3.4, the ratio (Δε / ε _⊥) of about 0.31 of the average dielectric anisotropy (Δε) and the vertical dielectric constant (ε _⊥) of the liquid crystal composition It is preferably in the range from 0.46.

The liquid crystal composition also has a phase transition temperature (T _ni ) of about 70 to 95 ° C. and a refractive index anisotropy (Δn) of about 0.103 or less.

As described above, the liquid crystal composition includes both a liquid crystal compound having a positive dielectric anisotropy and a liquid crystal compound having a negative dielectric anisotropy, thereby increasing the total dielectric constant in consideration of the vertical and horizontal dielectric constants of the liquid crystal composition, thereby increasing the liquid crystal storage capacity. The voltage holding capability can be enhanced.

Therefore, the area of the storage capacitor formed to assist the liquid crystal storage capacity can be reduced, and accordingly, the opening ratio can be increased by reducing or eliminating the area occupied by the storage electrode line 131.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of the invention.

By increasing the liquid crystal storage capacity and reducing the auxiliary storage capacity, the aperture ratio of the liquid crystal display device can be increased while enhancing the voltage holding capability, and the display failure can be reduced by reducing the kickback voltage.

Claims (15)

10 to 25% by weight of the first liquid crystal group including the neutral liquid crystal compound, 3 to 15% by weight of a second liquid crystal group comprising a liquid crystal compound having positive dielectric anisotropy, and 60 to 80 wt% of a third liquid crystal group including a liquid crystal compound having negative dielectric anisotropy Vertically oriented liquid crystal composition comprising a. In claim 1, The first liquid crystal group is represented by Formulas (I) to (III):

At least one of the liquid crystal compound represented by, Wherein R ₁ to R ₆ are the same as or different from each other and are each selected from an alkyl group or an alkoxy group having 1 to 10 carbon atoms Vertically oriented liquid crystal composition. In claim 2, The second liquid crystal group is represented by Formulas (IV) to (VIII):

At least one of the liquid crystal compound represented by, Wherein R ₇ to R ₁₁ are the same as or different from each other and are each selected from an alkyl group or an alkoxy group having 1 to 10 carbon atoms Vertically oriented liquid crystal composition. In claim 3, The third liquid crystal group is represented by Formulas (IX) to (XII):

At least one of the liquid crystal compound represented by, Wherein R ₁₂ to R ₁₉ are the same as or different from each other and are each selected from an alkyl group or an alkoxy group having 1 to 10 carbon atoms Vertically oriented liquid crystal composition. In claim 4, The average dielectric anisotropy (Δε) of the liquid crystal composition is -2.6 to -3.4 vertically aligned liquid crystal composition. In claim 5, The ratio of the average dielectric constant anisotropy (Δε) and the vertical dielectric constant (ε _⊥ ) of the liquid crystal composition (Δε / ε _⊥ ) is 0.31 to 0.46 vertically aligned liquid crystal composition. In claim 6, The liquid crystal composition is a vertically aligned liquid crystal composition having a phase transition temperature of 70 to 95 ℃ and refractive index anisotropy 0.103 or less. First substrate, A second substrate facing the first substrate, A pair of field generating electrodes formed on at least one of the first substrate and the second substrate, A liquid crystal layer interposed between the first substrate and the second substrate, and Inclination direction determination member which determines the inclination direction of the liquid crystal compound of the said liquid crystal layer Including, The liquid crystal layer is 10 to 25% by weight of the first liquid crystal group including the neutral liquid crystal compound, 3 to 15% by weight of a second liquid crystal group comprising a liquid crystal compound having positive dielectric anisotropy, and Liquid crystal composition containing 60 to 80 weight% of the 3rd liquid crystal group containing the liquid crystal compound which has negative dielectric anisotropy Liquid crystal display comprising a. In claim 8, The first liquid crystal group is represented by Formulas (I) to (III):

At least one of the liquid crystal compound represented by, Wherein R ₁ to R ₆ are the same as or different from each other and are each selected from an alkyl group or an alkoxy group having 1 to 10 carbon atoms Liquid crystal display. In claim 9, The second liquid crystal group is represented by Formulas (IV) to (VIII):

At least one of the liquid crystal compound represented by, Wherein R ₇ to R ₁₁ are the same as or different from each other and are each selected from an alkyl group or an alkoxy group having 1 to 10 carbon atoms Liquid crystal display. In claim 10, The third liquid crystal group is represented by Formulas (IX) to (XII):

At least one of the liquid crystal compound represented by, Wherein R ₁₂ to R ₁₉ are the same as or different from each other and are each selected from an alkyl group or an alkoxy group having 1 to 10 carbon atoms Liquid crystal display. In claim 11, Average dielectric anisotropy (Δε) of the liquid crystal composition is a liquid crystal display device of -2.6 to -3.4. In claim 12, Ratio (Δε / ε _⊥) is a liquid crystal display device of 0.31 to 0.46 of the average dielectric anisotropy (Δε) and the vertical dielectric constant (ε _⊥) of the liquid crystal composition. In claim 13, The liquid crystal composition has a phase transition temperature of 70 to 95 ℃ and refractive index anisotropy 0.103 or less. In claim 8, The inclination direction determining member includes a cutout formed in the field generating electrode or a protrusion formed on the field generating electrode.

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