TWI426121B - Liquid crystal composition for high-speed response time - Google Patents

Description

High-speed response time liquid crystal composition

The present invention relates to a nematic liquid crystal composition for realizing high-speed response time. More particularly, the present invention relates to a high-speed response time nematic liquid crystal composition having a high phase transition temperature (nematic phase-isotropic temperature) and high birefringence, and a liquid crystal display device using the liquid crystal composition. Rate and low rotational viscosity for high response time, no amorphous stains and low temperature stability.

As one type of flat display device, a liquid crystal display device uses an electrical property and a light characteristic of a liquid crystal injected into a panel to perform a work display function. Since the liquid crystal display device has various advantages such as small size, light weight, and low power consumption, it is widely used. Computer monitors and mobile phone terminals in many fields.

For example, the electro-optical modes used are twisted nematic (TN) mode, super-twisted nematic (STN) mode, optically compensated birefringence (OCB) mode, and electronically controlled birefringence ( Electrically controlled birefringence; ECB) mode and its variants. These modes utilize an electric field that is completely perpendicular to the substrate for each liquid crystal layer. In addition to these modes, for example, there is also a horizontal switching mode, that is, the electro-optical mode utilizes an electric field that is completely horizontal with each liquid crystal layer. In particular, electro-optic mode is used for desktop monitors of the latest liquid crystal displays and for application to multimedia displays.

For these displays, there is a need for new liquid crystal media with improved properties. In particular, there is a need to increase the response speed to achieve various applications. Therefore, there is a need for a liquid crystal medium having a low viscosity (η), and in particular, a liquid crystal medium having a low rotational viscosity (γ1). The rotational viscosity should be 75 milliPascal seconds (mPa s) or less, preferably 60 milliPascal seconds or less, and particularly preferably 55 milliPascal seconds or less. In addition to these parameters, the medium should exhibit a suitably wide range of nematic phases, sufficiently high birefringence ([Delta]n), and sufficiently high dielectric anisotropy ([Delta][epsilon]) to allow for low drive voltages.

The display of the present invention is preferably directed to an active matrix liquid crystal display (simply referred to as AMD) or a thin film transistor. However, the advantages of the liquid crystals of the present invention are in combination with other solutions known in the display.

Liquid crystal compositions suitable for liquid crystal displays, especially twisted nematic mode thin film transistor liquid crystal displays, are known in the art. However, these compositions have serious drawbacks, especially low response speed, low resistance, and high driving voltage.

In addition, thin film transistor liquid crystal display panels are widely used throughout the world, from cold regions such as polar regions to hot regions such as the equator. For this reason, the stability of the liquid crystal composition at low temperatures and high temperatures is very important. In particular, the panel cannot be used where the panel is exposed to extremely low temperatures below zero and thus causes precipitation of the crystal. This crystal precipitation phenomenon occurs when the mutual solubility of a single liquid crystal in the liquid crystal composition deteriorates at a low temperature.

However, liquid crystal compositions capable of satisfying all desired physical properties have not been developed at present. In particular, even if the physical properties such as response speed and dielectric anisotropy are satisfied, the liquid crystal composition cannot solve the problem of amorphous staining and low temperature stability.

Accordingly, the present invention provides a high speed response time liquid crystal composition that substantially obviates one or more of the problems caused by the limitations and disadvantages of the prior art.

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-speed response time nematic liquid crystal composition which can prevent amorphous stains and liquid crystal precipitation when applied to a panel at a low temperature, thereby exhibiting excellent low-temperature stability.

Another object of the present invention is to provide a high-speed response time nematic liquid crystal composition having a high response speed, a nematic phase-isotropic temperature of 80 ± 1 ° C or higher, a high refractive index anisotropy, and a low rotation. Viscosity and ensure a predetermined range of static viscosity and threshold voltage.

Another object of the present invention is to provide a high-speed response time nematic liquid crystal composition to solve the problem of deterioration during product operation, thereby ensuring high-temperature reliability.

Another object of the present invention is to provide a liquid crystal display device, and more particularly to a liquid crystal display device for a thin film transistor liquid crystal display monitor, comprising a nematic liquid crystal composition having a high response time.

In order to obtain these and other advantages of the present invention, specifically and broadly described herein, the present invention provides a nematic liquid crystal composition comprising: (a) selecting from the compounds of the following Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3 Two or more non-polar compounds; and (b) three or more polar compounds selected from the compounds of the following Chemical Formula 4, Chemical Formula 5, Chemical Formula 6, and Chemical Formula 7:

Wherein R is C2-C9 n-alkenyl, R1 to R8 are each independently a C1-C7 alkyl group, and X is hydrogen (H) or fluorine (F).

The liquid crystal composition is composed of (a) two or more non-polar compounds in a weight ratio of 50% to 58% and (b) three or more polar compounds in a weight ratio of 42% to 50%.

According to another aspect, the present invention provides a liquid crystal display device comprising the nematic liquid crystal composition of the present invention. The liquid crystal display device is preferably an active twisted nematic mode liquid crystal display device, and is preferably a liquid crystal display device of a thin film transistor-liquid crystal display.

It is to be understood that the foregoing general description of the invention and the claims

The invention will be described below in conjunction with the drawings.

The twisted nematic mode is a nematic liquid crystal mode of operation. The physical properties of the liquid crystal compositions applied to the twisted nematic mode liquid crystal display panel are generally related to each other. That is, considering the correlation equation of the correlation parameter of the response time of the liquid crystal composition, the response speed of the liquid crystal display is divided into an opening time and a closing time, in which an electric field is applied at the opening time and an electric field is stopped at the closing time, which is expressed by the following equation.

In Equations 1 and 2, γ1 is the rotational viscosity, d is the crystal gap, εo is the dielectric constant, Δε is the dielectric anisotropy (Δε=ε∥-ε┴), V is the operating voltage, and Vth is (Fredric's conversion) The threshold voltage, and Keff is the effective spring constant.

Among the physical properties of the liquid crystal composition, when the composition has a low rotational viscosity, a high elastic constant, and a high dielectric anisotropy, a high-speed response time can be ensured. At this time, it is necessary to choose between the rotational viscosity, the elastic constant, and the nematic phase-isotropic phase transition temperature (TNI).

Further, as shown in Equation 3 below, the crystal gap of the liquid crystal display panel, the refractive index anisotropy of the liquid crystal composition, and the wavelength of the incident light represent the first minimum of the Gooch-Tarry of the twisted nematic liquid crystal cell. Based on the determined crystal gap, the refractive index anisotropy of the liquid crystal composition applied to the twisted nematic liquid crystal cell was determined.

A liquid crystal display panel for a monitor generally uses a liquid crystal composition of a thin film transistor liquid crystal display for twisting a nematic mode, and has an operating temperature of -10 to 75 ° C and a low response speed (10 msec).

In addition, when the monitor is operated for a long period of time at a lower working temperature, the generated heat causes deterioration and ghosting during display of the moving image. In addition, when the liquid crystal composition is applied to the panel, the pretilt angle and characteristics such as the working temperature or the response speed are high, and thus there is a disadvantage in that an amorphous stain is caused.

According to the applied voltage, the liquid crystal display device uses a nematic liquid crystal phase to adjust the arrangement of liquid crystal molecules of the liquid crystal composition, and controls the light transmittance to realize an image. For this reason, for liquid crystal display devices, the temperature range maintained by the liquid crystal phase is necessary due to the risk of deterioration due to heat generated during long-term operation, and the nematic phase-isotropic phase transition temperature (TNI) is very high. important. Further, in consideration of the fact that the liquid crystal display device is propagated to the polar region, it is necessary to ensure a crystal-nematic phase transition temperature (TCN) from which the nematic liquid crystal phase is initially initiated. In addition, high-speed response time liquid crystal compositions are required to provide high-quality, high-capacity display information processing, superior information processing, and superior motion picture display for mobile phones, monitors, and televisions.

In particular, in order to perfectly achieve an afterimage-free moving image, the operating temperature, especially the upper limit temperature, should be at least 80 ± 1 ° C, and the response speed should be 5 milliseconds or less. Further, as shown in Equation 1, Equation 2, and Equation 3, in the case where the crystal gap is 3.4 μm, the dielectric composition should have a dielectric anisotropy of 4.5 ± 0.5 in order to obtain a response speed of 5 msec, and the rotational viscosity should be 55 mPas or less, and the refractive index anisotropy should be 0.1210 ± 0.005. Further, the upper limit temperature of the liquid crystal phase should be 80 ± 1 °C. In addition, when the liquid crystal composition is applied to the panel to avoid occurrence of amorphous stains, while considering the working temperature and the response speed, the pretilt should be 5.5 or less. Due to the increase in the pretilt angle, amorphous stains are considered in view of sensitivity to changes in transmittance.

Accordingly, the present invention provides a nematic liquid crystal composition of a thin film transistor liquid crystal display having a nematic phase-isotropic phase transition temperature (TN-I) of 80±1° C., having a dielectric orientation of 4.5±0.5. Anisotropic, rotational viscosity of 55 mPas or less and refractive index anisotropy of 0.1210 ± 0.005. When the panel of the liquid crystal display device has a crystal gap of 3.4 μm, the display device has an upper limit of 80 ± 1 ° C or higher. Temperature and response speed of 5 milliseconds or less. Further, the liquid crystal composition has a crystallization temperature (TC-N) of -30 ° C or lower. The term "crystallization temperature" as used herein denotes the temperature at which a substance changes from a solid phase to a nematic liquid crystal phase. The liquid crystal composition was crystallized at a temperature of -20 °C. However, this crystallization temperature is not suitable due to a change in the use environment of the liquid crystal display device and a liquid crystal medium having a lower crystallization temperature. The liquid crystal composition of the present invention ensures a crystallization temperature of -30 ° C or lower, and thus the characteristics of the liquid crystal display device are considerably improved.

In particular, the liquid crystal composition of the present invention has a pretilt angle of 5.5°, and when the liquid crystal display panel has a crystal gap of 3.4 μm, amorphous stains can be avoided.

The fast-responsive nematic liquid crystal composition ensures all physical properties by the optimal combination of individual liquid crystal compounds.

In particular, the liquid crystal composition is composed of a predetermined composition having no polar or polar component. The liquid crystal composition comprises: (a) two or more non-polar compounds selected from the compounds represented by Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3; and (b) represented by Chemical Formula 4, Chemical Formula 5, Chemical Formula 6, and Chemical Formula 7. Three or more polar compounds selected from the compounds.

In the above formula, R is C2-C9 n-alkenyl, R1 to R8 are each independently a C1-C7 alkyl group, and X is hydrogen (H) or fluorine (F).

With respect to the liquid crystal composition, in a preferred embodiment of the non-polar composition, (i) one or more compounds are selected from each of Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3, and (ii) one of each of Chemical Formula 1 and Chemical Formula 2 is selected. Or a plurality of compounds, (iii) one or more compounds selected from each of Chemical Formula 1 and Chemical Formula 3, or (iv) one or more compounds selected from Chemical Formula 2 and Chemical Formula 3, respectively.

With respect to the liquid crystal composition, in a preferred embodiment of the polar composition, (i) one or more compounds are selected from each of Chemical Formula 4, Chemical Formula 5, Chemical Formula 6, and Chemical Formula 7, and (ii) is from Chemical Formula 4, Chemical Formula 5, and Chemical Formula. Each of 6 selects one or more compounds, (iii) selects one or more compounds from each of Chemical Formula 4, Chemical Formula 5, and Chemical Formula 7, and (iv) selects one or more compounds from Chemical Formula 4, Chemical Formula 6 and Chemical Formula 7, respectively, or (v) One or more compounds are each selected from Chemical Formula 5, Chemical Formula 6, and Chemical Formula 7.

Therefore, the liquid crystal composition of the present invention is composed of a composition selected from non-polar compounds and a composition selected from polar compounds.

The present inventors have found that when the liquid crystal composition has a high pretilt angle, i.e., 5.5 or more, an amorphous speckle is formed in the thin film transistor-liquid crystal display panel, wherein the pretilt angle is related to the ratio of the nonpolar component in the liquid crystal composition. Therefore, in consideration of this fact, the present invention uses (a) the amount of the non-polar compound is 50% or more by weight, and (b) the amount of the polar compound is 50% or less by weight. In particular, the present invention is characterized in that the liquid crystal composition uses (a) a nonpolar compound in a weight ratio of 50 to 58%, a weight ratio of 52 to 56%, and (b) a polar compound in a weight ratio of 42 to 50%. A weight ratio of 44 to 48% is preferred.

By controlling the non-polar and polar components in accordance with the above ratio, the present invention can reduce the pretilt angle to 5.5 or less, whereby amorphous stains can be avoided.

Depending on the total weight of the liquid crystal composition, when the non-polar compound exhibits a weight ratio exceeding 58%, the pretilt angle is more than 5.5° and an amorphous stain appears. Further, when the content ratio of the nonpolar compound is less than 50%, the viscosity is increased, whereby a rotational viscosity of 55 mPas or less and a response speed of 5 msec cannot be obtained.

The non-polar compound of the liquid crystal composition is divided into 100 equal parts by weight, and the non-polar compound contains 60 to 85 parts by weight of the compound of Chemical Formula 1, 0 to 10 parts by weight of the compound of Chemical Formula 2, and 15 to 30 parts by weight of the compound of Chemical Formula 3.

The entire polar compound of the liquid crystal composition is divided into 100 equal parts by weight, and the polar compound contains 20 to 40 parts by weight of the compound of Chemical Formula 4, 14 to 30 parts by weight of the compound of Chemical Formula 5, and 15 to 35 equal parts. A compound of the formula 6 having a weight, and a compound of the formula 7 of 10 to 20 parts by weight.

The polar compound contains one or more compounds having the structure of Chemical Formula 4, one or more compounds having the structure of Chemical Formula 5, and one or more compounds having the structure of Chemical Formula 6. More specifically, the polar compound contains two or more compounds of Chemical Formula 4 having different carbon numbers, two or more compounds of Chemical Formula 5 having different numbers of carbon atoms, and Chemical Formula 6 having a different number of carbon atoms. Two or more compounds.

Further, the compound having the structure of Chemical Formula 7 is a group consisting of a compound selected from Chemical Formulas 7a and 7b, and a combination thereof.

In the above chemical formula, each R8 is a C1-C7 hydrocarbon group.

In Chemical Formulas 1, 2, and 3, each individual liquid crystal compound is used in excess according to the range defined herein, and the nematic phase-isotropic phase transition temperature (TNI) is excessively reduced to 79 ° C or less, and Ensure high temperature reliability of the panel. Further, when the content is too low, the viscosity and the rotational viscosity are increased, whereby the disadvantage is that a response time of 6 msec or less cannot be obtained.

Further, when each of the liquid crystal compounds of Chemical Formulas 4, 5, and 6 is used in excess beyond the above-defined range, the refractive index anisotropy or viscosity is greatly increased, so that a fast response time of 6 msec or less and an expectation cannot be achieved. The refractive index anisotropy of the range. Further, when the content is too low, there is a disadvantage in that the refractive index anisotropy is lower than the desired level.

When the liquid crystal compound of Chemical Formula 7 exceeds the above-defined range, the nematic phase-isotropic phase transition temperature (TNI) increases, but the crystal nematic phase transition temperature (TCN) rapidly increases, and the low temperature liquid crystal phase cannot be ensured, and A low response time of 5 milliseconds or less cannot be achieved. In addition, when the content is extremely low, the nematic phase-isotropic phase transition temperature (TNI) is rapidly lowered to 78 ° C or lower, which is disadvantageous in that the high-temperature reliability of the panel cannot be ensured.

Meanwhile, the non-polar compound of Chemical Formulas 1, 2, and 3 having a 2-ring structure used in the present invention can secure a low viscosity and a desired level of refractive index anisotropy and dielectric anisotropy. In addition, the individual liquid crystal compounds of Chemical Formulas 1 and 7 ensure low viscosity and a lower lower limit crystalline nematic phase transition temperature (TCN).

That is, as for the liquid crystal compound, the single liquid crystal compound of Chemical Formula 1 has a low viscosity and a low rotational viscosity, contributes to a short response time, and therefore is preferably contained as an indispensable component.

Further, the compound of Chemical Formula 1 contains at least one selected from the group consisting of the compounds shown. The compound of Chemical Formula 1 contains a compound of Chemical Formula 1a in a weight ratio of 20 to 75%, and a compound of Chemical Formula 1b in a weight ratio of 10 to 40%, particularly preferably a compound having a weight ratio of 40 to 60% of the chemical formula 1a and a weight ratio of 15 to 30% of the compound of the chemical formula 1b is more preferred.

Each R1 is a C1-C7 hydrocarbon group.

In particular, the present invention utilizes the compound of Chemical Formula 2 to ensure an equal temperature range among the liquid crystal compositions. The use of the compound of Chemical Formula 2 ensures a desired range of viscosity and nematic phase-isotropic phase transition temperature, as well as achieving a high speed response time of 5 milliseconds or less.

The alkoxy compound of Chemical Formula 3 can be arbitrarily present, and as described above, helps to ensure a low viscosity and a moderate temperature range of the liquid crystal composition.

The individual liquid crystal compounds of Chemical Formulas 4, 5, and 6 perform elevation actions to ensure refractive index anisotropy and dielectric anisotropy of the liquid crystal composition in the temperature range of the nematic liquid crystal phase and the high-speed response time. .

The single liquid crystal compound of Chemical Formula 7 exhibits a high temperature range, thereby ensuring a nematic phase-isotropic phase transition temperature (TNI) of 79 ° C or higher, thereby ensuring high temperature reliability due to heat generation during operation of the liquid crystal display device, which Points are considered to be especially important.

The liquid crystal medium further contains a generally used amount of an additive and a chiral dopant. The additional component exhibits a concentration of from 0.1 to 10%, preferably from 0.1 to 6%, based on the total weight of the compound. Each compound is preferably used at a concentration of from 0.1 to 3%.

Further, the liquid crystal composition of the present invention uses a combination of nematic liquid crystal, smectic liquid crystal, and cholesteric liquid crystal, and these liquid crystals are generally known to improve the characteristics of the liquid crystal composition. However, when a large amount of the liquid crystal compound is excessively increased, the desired properties of the liquid crystal composition are deteriorated. The amount of increase is determined according to the demand of the nematic liquid crystal composition.

The aforementioned nematic liquid crystal composition applied to a liquid crystal display device can exhibit excellent physical properties.

Accordingly, the present invention provides a liquid crystal display device comprising a nematic liquid crystal composition having a high response time.

Preferably, the liquid crystal display panel using the liquid crystal composition of high-speed response time has a brightness of 285 to 315 candelas per square centimeter (cd/cm ² ), a contrast ratio of 760 to 840, and a response speed of 4.75 to 5.75 msec (when the operation For liquid crystal displays of 60 Hz, 6 volts, -30 ° C to 80 ± 1 ° C, and all liquid crystal display devices suitable for nematic liquid crystal compositions, especially for thin film transistors with 19-inch resolution SXGA monitors -LCD Monitor.

These monitors show a 20% increase in brightness compared to the brightness of 250 candelas per square centimeter for conventional thin film transistor-liquid crystal displays used in monitors, and the response speed is improved compared to the conventional 8 milliseconds. 38%, upper and lower operating temperature range increased from -20 ° C to 75 ° C range to -30 ° C to 80 ± 1 ° C range. Therefore, the monitor film transistor liquid crystal display is suitable for achieving fast moving images and exhibits a relatively high reliability in generating heat during operation of the device or when the temperature is below zero.

That is, the present invention provides a display device which can charge a high-speed responsive nematic liquid crystal composition as a liquid crystal material together with a suitable additive into a liquid crystal cell, and can be used for various liquid crystal displays. The liquid crystal display device is preferably an active twisted nematic mode liquid crystal display device, and more particularly a twisted nematic mode liquid crystal display device for a thin film transistor-liquid crystal display. Further, the liquid crystal display device includes a high-quality, high-capacity display device such as a mobile phone, a monitor, and a television, and the liquid crystal display device is preferably a monitor.

By coating an orientation film on the array substrate and the C/F substrate, the thin film transistors in the array substrate are arranged on the glass substrate in pixel units, and each pixel in the C/F substrate includes red/green/ The blue sub-pixel is then rubbed and oriented, a liquid crystal composition is injected into the space provided between the two, and a polarizing plate is adhered to the array substrate and the C/F substrate to fabricate a twisted nematic mode liquid crystal display device.

Besides the liquid crystal display device using a liquid crystal composition, those skilled in the art are familiar with the details of the liquid crystal display device, and thus the detailed configuration of the liquid crystal display device and the operation principle thereof are omitted.

example

The invention will now be described in more detail in connection with the following examples. These examples are for illustrative purposes only and are not to be considered as limiting the scope and spirit of the invention.

<Examples 1 to 3>

A nematic liquid crystal composition was prepared by mixing a nonpolar compound (N-1 to N4) and a polar compound (P-1 to P-8) in accordance with the composition and content described in Table 1 (unit: wt%) below.

[Experimental Example 1]

For each liquid crystal composition, physical properties such as crystallization temperature and nematic phase-isotropic phase transition temperature are measured in accordance with the general method disclosed in Korean Patent Application No. 2006-0045599, and the results obtained are as shown in Table 2 below. .

As can be seen from Table 2 above, the liquid crystal composition of the present invention exhibits excellent properties such as refractive index anisotropy, refractive index, dielectric anisotropy, rotational viscosity, and relatively low crystallization temperature as well as excellent stability at low temperatures. Further, the liquid crystal composition has an optimum composition, so that it can have an upper limit temperature of 79 ° C or higher and a response speed of 5 msec or less.

[Experimental Example 2]

The pretilt angles and various contents of the nonpolar and polar components contained in the liquid crystal compositions in these examples and comparative examples were measured, and the results obtained therefrom are shown in Table 4. At this time, the composition of the comparative example is as shown in Table 3. As can be seen from Table 4, the pretilt angle of the liquid crystal composition associated with the amorphous stain generated by the thin film transistor-liquid crystal display panel was compared.

As can be seen from Table 4, Examples 1, 2 and 3 of the present invention use a non-polar component having a weight ratio of 54% or less, thereby having a pretilt angle of 5.5 or less, thereby causing no absence in the panel. Shape the stain. On the other hand, Comparative Example 1 used a non-polar component higher than the present invention, thereby having a pretilt angle higher than 5.5, resulting in an amorphous stain in the panel.

[Experimental Example 3]

For each of the compositions of the examples of the present invention, after storing these compositions at -20 ° C for two weeks in a freezer, the crystal precipitation was confirmed by pass to evaluate low temperature stability (Table 5).

As can be seen from Table 5, Examples 1, 2 and 3 of the present invention did not exhibit crystal precipitation after two weeks of storage, which means that the composition of the present invention can ensure low-temperature reliability.

As apparent from the foregoing, the nematic liquid crystal composition has no amorphous stain and exhibits excellent low-temperature reliability and high-speed response time, thereby being suitable for liquid crystal display devices of high-quality and large-capacity display information processing, and exhibiting excellent performance. Information processing and motion image display features. This composition solves the deterioration problem caused by long-term operation, thereby ensuring high-temperature reliability of the product and realizing motion images without image sticking.

Although the present invention has been disclosed above in the foregoing embodiments, it is not intended to limit the invention. It is within the scope of the invention to be modified and modified without departing from the spirit and scope of the invention. Please refer to the attached patent application for the scope of protection defined by the present invention.

Claims (15)

A nematic liquid crystal composition comprising: (a) two or more non-polar compounds selected from the compounds of the following Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3; and (b) from the following Chemical Formula 4, Chemical Formula 5, Chemical Formula 6 or more than three or more polar compounds selected from the compounds of Chemical Formula 7: [Chemical Formula 6] Wherein R is C ₂ -C ₉ n-alkenyl, R ₁ to R ₈ are each independently C ₁ -C ₇ alkyl, and X is hydrogen (H) or fluorine (F). The nematic liquid crystal composition according to Item 1, wherein the liquid crystal composition uses (a) a non-polar compound in a weight ratio of 50% to 58%, and (b) a polar compound in a weight ratio of 42%. Up to 50%. The nematic liquid crystal composition according to Item 2, wherein the liquid crystal composition has a weight ratio of (a) a nonpolar compound of 52% to 56%, and (b) a polar compound is 44% by weight. Up to 48%. The nematic liquid crystal composition according to Item 2, wherein the non-polar compound of the liquid crystal composition is divided into 100 equal parts by weight, and the non-polar compound contains 60 to 85 parts by weight of the compound of Chemical Formula 1, 0 to 10 parts by weight of the compound of Chemical Formula 2, and 15 to 30 parts by weight of the compound of Chemical Formula 3. The nematic liquid crystal composition according to Item 2, wherein the polar compound of the liquid crystal composition is divided into 100 equal parts by weight, and the polar compound comprises 20 to 40 parts by weight of the compound represented by Chemical Formula 4, 14 to 30 parts by weight of the compound of Chemical Formula 5, 15 to 35 parts by weight of the compound of Chemical Formula 6, and 10 to 20 parts by weight of the compound of Chemical Formula 7. The nematic liquid crystal composition according to Item 1, wherein the compound comprises the structure of Chemical Formula 7 selected from the group consisting of the compounds of Chemical Formulas 7a and 7b, and combinations thereof, Each of the R ₈ systems is a C ₁ -C ₇ hydrocarbon group. The nematic liquid crystal composition according to Item 1, wherein the compound of Chemical Formula 1 comprises at least one selected from the group consisting of the compounds represented by Chemical Formulas 1a and 1b, [Chemical Formula 1b] Each of R ₁ is a C ₁ -C ₇ hydrocarbon group. The nematic liquid crystal composition according to Item 7, wherein the compound of Chemical Formula 1 comprises a compound of Chemical Formula 1a in a weight ratio of 20% to 75%, and a compound of Chemical Formula 1b in a weight ratio of 10% to 40%. The nematic liquid crystal composition according to claim 8, wherein the compound of Chemical Formula 1 comprises a compound of Chemical Formula 1a in a weight ratio of 40% to 60%, and a compound of Chemical Formula 1b in a weight ratio of 15% to 30%. The nematic liquid crystal composition of claim 1, further comprising an additive and a chiral dopant. The nematic liquid crystal composition of claim 10, wherein the additive and the chiral dopant exhibit a concentration of 0.1% to 10%, respectively, based on the total weight of the compound. The nematic liquid crystal composition of claim 11, wherein the additive and the chiral dopant exhibit a concentration of 0.1% to 6%, respectively, based on the total weight of the compound. The nematic liquid crystal composition of claim 12, wherein the additive and the chiral dopant exhibit a concentration of 0.1% to 3%, respectively, based on the total weight of the compound. The nematic liquid crystal composition according to Item 1, wherein the nematic liquid crystal composition has a pretilt angle, and the pretilt angle should be 5.5 or less. A liquid crystal display device comprising the nematic liquid crystal composition according to claim 1 of the claim.