WO2017116075A1

WO2017116075A1 - Liquid crystal composition and liquid crystal display device including same

Info

Publication number: WO2017116075A1
Application number: PCT/KR2016/015128
Authority: WO
Inventors: 최진욱; 송정인; 윤성일
Original assignee: 주식회사 동진쎄미켐
Priority date: 2015-12-31
Filing date: 2016-12-22
Publication date: 2017-07-06
Also published as: CN108473870A; TW201736578A; KR20170079970A

Abstract

The present invention relates to a liquid crystal composition and a liquid crystal display device. The liquid crystal composition has excellent low-temperature stability and a high phase transition temperature, and can exhibit a low rotational viscosity while exhibiting sufficient refractive index anisotropy and dielectric anisotropy. Therefore, by using the liquid crystal composition, a liquid crystal display device having a low threshold voltage, enabling a fast response, and capable of operating in a wide temperature range can be provided.

Description

【Specification】

[Name of invention]

Liquid crystal composition and liquid crystal display comprising the same

Technical Field

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

[Technique to become background of invention]

Liquid crystal displays (LCDs) are used in watches, electronic calculators, various electrical devices, measuring devices, automotive panels, word processors, electronic notebooks, printers, computers, televisions, and the like. Representatively liquid crystal display system

TNCTwi st nemat i c), STN (Super ᅳ twi sted nemat i c), IPS (In-plane swi tching),

FFS (Fr Inge Field Switching) and VA (Vertical Alignment) ^■ .

The single liquid crystal compound used in such a liquid crystal display device is about 200 to

It has a molecular weight of 600g / iiK) l and a rod-shaped molecular structure. Usually, the molecular structure of the liquid crystal compound is divided into a core group that maintains straightness, a terminal group having flexibility, and an lage group for a specific use. Of these, the physical properties of the liquid crystal compound and the composition including the same may be controlled by adjusting the type of the substituent introduced into the end group. Specifically, a flexible group is introduced at one or both ends (alkyl, alkoxy or alkenyl group, etc.) to secure flexibility, or at both ends, polar groups (F, CN, 0CF _3, etc.) ) Can be used to control properties such as permittivity.

The liquid crystal compound used in the liquid crystal display device described above is capable of low voltage driving and high speed response, and is required to be operable in a wide temperature range. Specifically, in order to drive stably in a wide temperature range, the liquid crystal material exhibits stable physical properties at about -25 ^° C or lower (low temperature stability), and is required to have a high transparent point. And, for low voltage driving and high speed response, the liquid crystal material is required to have a large absolute value of dielectric anisotropy, low rotational viscosity, and have an appropriate modulus of elasticity (K _u , κ ₂₂ , Κ ₃₃ average value).

The required physical properties of such liquid crystal materials include one or two kinds of liquid crystal compounds. It is impossible to satisfy | fill by using, Usually, 7-20 types of liquid crystal compounds are mix | blended and satisfied.

However, a negative liquid crystal material having a negative dielectric anisotropy has a polar substituent on the side of the molecule, which causes a problem that the rotational viscosity is greatly increased even if the dielectric anisotropy is slightly changed compared to the positive liquid crystal material. In addition, the liquid crystal compound used to adjust the dielectric anisotropy, refractive index anisotropy, and the like has a problem of limiting the driving silver range of the liquid crystal display by lowering the low temperature stability.

Accordingly, the development of a liquid crystal composition for providing a liquid crystal display device having a high driving speed and having a wide driving temperature range is required. [Content of invention]

Problem to be solved

The present invention provides a liquid crystal composition having excellent low temperature stability and high phase transition temperature and capable of exhibiting low rotational viscosity.

The present invention also provides a liquid crystal display device comprising the liquid crystal composition.

[Measures of problem]

Hereinafter, a liquid crystal composition and a liquid crystal display including the same according to a specific embodiment of the present invention will be described.

According to an embodiment of the present invention, there is provided a liquid crystal composition comprising 1 to 15 parts by weight of the liquid crystal compound represented by Formula 1 and 1 to 15 parts by weight of the liquid crystal compound represented by Formula 2 based on 100 parts by weight of the total liquid crystal compound: do.

In Formula 1, R ¹ is an alkyl group having 1 to 5 carbon atoms

[Formula 2]

In Formula ^2, R 2 is an alkyl group having 1 to 5 carbon atoms.

The liquid crystal compound of Formula 2 has the advantage of improving the low refractive index and low reliability by the vinyl group, while having the characteristics of simultaneously exhibiting high refractive index, high phase transition temperature and low rotational viscosity of the bicyclonucleic acid having a vinyl group . However, the liquid crystal compound of Formula 2 lowers the low temperature stability of the liquid crystal composition and has a disadvantage of poor solubility.

However, when the liquid crystal compound of Chemical Formula 2 is used together with the liquid crystal compound of Chemical Formula 1, low temperature stability and solubility can be greatly improved, and rotational viscosity can be significantly lowered. Accordingly, the liquid crystal composition according to the exemplary embodiment of the present invention including the liquid crystal compounds of Chemical Formulas 1 and 2 is expected to be applied to the liquid crystal display to lower the threshold voltage and improve the response speed.

In the general formula 1 R ¹ may be a methyl, ethyl, n- propyl, i so- propyl, n- butyl, sec- butyl, i so- butyl, tert- butyl, n- pentyl or neo- pentyl. Among these, R ¹ may be selected as a profile to show better refractive index, phase transition temperature, and rotational viscosity.

The liquid crystal compound of Formula 1 is included in an amount of 1 to 15 parts by weight based on 100 parts by weight of the total liquid crystal compound included in the liquid crystal composition. If the content of the liquid crystal compound of Formula 1 is less than the above range, low temperature stability and rotational viscosity may not be sufficiently improved. If the content of the liquid crystal compound of Formula 1 exceeds the range, the refractive index may be lowered.

The liquid crystal compound of Formula 1 may increase solubility of the liquid crystal compound of Formula 2 and may be included together with the liquid crystal compound of Formula 2 to significantly improve low temperature stability and rotational viscosity of the liquid crystal composition.

In Formula 2, R ² may be methyl, ethyl, n-propyl, i so-propyl, n-butyl, sec-butyl, i so-butyl, tert-butyl, n-pentyl or neupentyl. Among them, R ² is selected from any one of ethyl, n-propyl and n-butyl, You can secure the effect more effectively.

As the liquid crystal compound of Chemical Formula 2, two or more kinds of black silver selected from the liquid crystal compound represented by Chemical Formula 2 may be used. The liquid crystal compound of Formula 2 is used in 1 to 15 parts by weight based on 100 parts by weight of the total liquid crystal compound contained in the liquid crystal composition. If the content of the liquid crystal compound of Formula 2 is less than the above range, there is a fear that the refractive index and the phase transition temperature of the liquid crystal composition may be lowered, and if it exceeds the above range, the low temperature stability may be significantly reduced.

The liquid crystal composition according to the embodiment may include various liquid crystal compounds and other additives known in the art to which the present invention pertains, except that the liquid crystal compounds of Formulas 1 and 2 are included.

For example, the liquid crystal composition may further include a liquid crystal compound represented by Formula 3 below.

Each independently represent a radical of any one of hydrogen and alkyl of 1 to 15 carbon atoms, or black so that at least one of the radicals is substituted with halogen or one or more -CH ₂ -oxygen atoms are not directly connected. , -CH = CH-, -0— ， -C0-0-, — 0— CO— or —0— C0- 0- radicals replaced by

The A ³ and A ⁴ rings are each independently 1,4-cyclohexylene, tetrahydropyranylene or 1, 4-phenylene.

Unless otherwise specified herein, the following terms may be defined as follows.

Halogen may be fluorine (F), chlorine (C1), bromine (Br) or iodine (I).

The alkyl radical having 1 to 15 carbon atoms may be a straight chain, branched chain or cyclic alkyl radical. Specifically, an alkyl radical having 1 to 15 carbon atoms may be a straight chain alkyl radical having 1 to 10 carbon atoms; Straight chain alkyl radicals having 1 to 5 carbon atoms; Branched or cyclic alkyl radicals having 3 to 10 carbon atoms; Or a branched or cyclic alkyl radical having 3 to 5 carbon atoms. More specifically, the alkyl radical having 1 to 15 carbon atoms may be methyl, ethyl, n-propyl, i so-propyl, n-butyl, i so-butyl, tert-butyl, n-pentyl, i so-pentyl or cyclonucleus, etc. Can be. And, an alkyl radical having 1 to 15 carbon atoms may have one or more -CH ₂ -of the radical -C≡C-, -CH-CH-, -0-, -C0-0-, —OC0- or-()- Can be replaced with a radical substituted with C0_0-. For example, the methyl radical may be replaced by a vinyl radical (-CH = CH-H) in which-(¾- of the methyl radical (-CH ₂ -H) is substituted with -CH = CH-, provided that One or more of -c¾- may be substituted with the substituents described above so that the oxygen atoms are not directly connected.

In addition, alkyl radicals having 1 to 15 carbon atoms may be replaced with radicals in which one or more H of the radicals is replaced by halogen. In one example, the methyl radical may be replaced with a perfluoromethyl radical (_CF ₃ ) in which all H of the methyl radical (_C¾) is substituted with F.

As the liquid crystal compound of Chemical Formula 3, it is selected so as to advantageously control the transparent point, the rotational viscosity, the refractive anisotropy, the dielectric anisotropy while maintaining a high specific resistance.

Prize

In the formulas, the same as defined in R ²¹ and formula (3). Addition The compound of Formula 3 may be included in an amount of 10 to 50 parts by weight based on 100 parts by weight of the total liquid crystal compound included in the composition in order to implement the above-described physical properties.

On the other hand, the liquid crystal composition may further include a liquid crystal compound represented by the following formula (4).

In Formula 4, R ³¹ and R ³² are each independently a radical of any one of hydrogen and alkyl having 1 to 15 carbon atoms, or black is 1 of the radicals. -C≡C-, -CH = CH—, -0-, -C0-0-, -0-CO- or in order that at least H is substituted with halogen or one or more -CH ₂ -oxygen atoms are not directly connected Radicals replaced by -0-CO- 0-,

A ⁵ and A ⁷ ring are each independently 1,4-cyclohexylene, tetrahydropyranylene or 1, 4-phenylene,

A ⁶ ring is 1, 4-cyclonuylene, tetrahydropyranylene, 1, 4-phenylene or 1, 4-phenylene in which at least one H is substituted with halogen,

0 is an integer of 1 or 2.

When 0 is 2 in Formula 4, two A ⁶ rings may be identical to or different from each other.

As the liquid crystal compound of Chemical Formula 4, it is possible to advantageously control the anisotropy of the transparent point, the rotational viscosity, the refraction, and the dielectric anisotropy while maintaining a high specific resistance.

[4-8]

In the above formula, R ³¹ and R ³² are the same as defined in the formula (4). In addition, equivalence parenthesis "()" in the formula of the present specification means that it can be substituted with the substituents described in the parenthesis. More specifically,-(F) means that hydrogen or fluorine can be bonded to the site.

The liquid crystal compound of Chemical Formula 4 may be included in an amount of 5 to 40 parts by weight based on 100 parts by weight of the total liquid crystal compound included in the composition in order to implement the above-described physical properties. On the other hand, the liquid crystal composition may further include a liquid crystal compound represented by the formula (5).

In Chemical Formula 5, R ⁴¹ and R ⁴² are each independently a radical of any one of hydrogen and alkyl having 1 to 15 carbon atoms, or at least one H in the radical is substituted with halogen or at least one -CH ₂ -addition. Radicals replaced by -C≡C-, -CH = CH-, -0-, -C0-0-, -0-C0- or -0-C0- 0- so that the small atoms are not directly connected,

A ⁸ and A ⁹ ring are each independently 1,4-cyclonuylene, tetrahydropyranylene, 1,4-phenylene or 1,4-phenylene in which at least one H is substituted with halogen,

m is an integer between 0 and 2.

As the liquid crystal compound of Chemical Formula 5, a compound selected from liquid crystal compounds having the following structure may be used to advantageously control the transparent point, the refractive index anisotropy, and the dielectric anisotropy while maintaining a high specific resistance.

[5-4]

In the above formula, R ⁴¹ and R ⁴² are the same as defined in the formula (5). The liquid crystal compound of Chemical Formula 5 may be included in an amount of 10 to 75 parts by weight based on 100 parts by weight of the total liquid crystal compound included in the composition to implement the above-described physical properties.

On the other hand, the liquid crystal composition may further include a liquid crystal compound represented by the following formula (6).

In Formula 6, R ⁵¹ and R ⁵² are each independently a radical of any one of hydrogen and alkyl having 1 to 15 carbon atoms, or at least one H in the radical is substituted with halogen, or at least one -CH ₂ -is oxygen Radicals replaced by-(: ≡0, -CH-CH-, -0-, -C0-0-, -0— CO- or -CKX) -0- so that the atoms are not directly connected,

_A io, A ¹¹ and A ¹² are each independently 1,4-cyclonuylene, tetrahydropyranylene, 1,4-phenylene or 1,4-phenylene in which at least one H is substituted with halogen,

Z ¹ and Z ² are each independently -CH ₂ CH _2- , ^' -CH = CH—, -CH ₂ 0-, -0CH ₂ -,-C≡C—, -C¾CF _2- , -CHFCHF-,- CF ₂ CH ₂ —, -CH ₂ CHF-, -CHFCH _2- , -C ₂ F _4- , -0-, -COO—, -0C0-, -CF ₂ 0- or -0CF _2- ,

nl and n3 are each independently 0 or 1, and the sum of nl and n3 is 1 or 2,

n2 and n4 are each independently an integer between 0 and 2. As the liquid crystal compound of Chemical Formula 6, a transparent point, a rotational viscosity, refractive index anisotropy, and dielectric anisotropy can be advantageously used while maintaining a high specific resistance.

In the above formula, R ⁵¹ and R ⁵² are the same as defined in formula (6). In particular, when using the liquid crystal compound represented by 6-1 as the liquid crystal compound of Formula 6 can exhibit a lower rotational viscosity it is very advantageous to provide a liquid crystal composition for high-speed response.

The compound of Formula 6 may be included in an amount of 0 to 10 parts by weight based on 100 parts by weight of the total liquid crystal compound included in the composition to implement the above-described physical properties.

The liquid crystal composition may include at least one or more liquid crystal compounds of the above-described liquid crystal compounds of Chemical Formulas 3 to 6 together with the liquid crystal compounds of Chemical Formulas 1 and 2 to exhibit high negative dielectric anisotropy and to have excellent low stability and low rotational viscosity. The liquid crystal material shown can be provided. For example, the liquid crystal composition may include all the liquid crystal compounds of Chemical Formulas 1 to 5 described above. Specifically, the liquid crystal composition is 1 to 15 parts by weight of the liquid crystal compound represented by Formula 1, 1 to 15 parts by weight of the liquid crystal compound represented by Formula 2, 10 to 50 parts by weight of the above formula It may include a liquid crystal compound represented by 3, 5 to 40 parts by weight of the liquid crystal compound represented by the formula (4) and 10 to 75 parts by weight of the liquid crystal compound represented by the formula (5). At this time, the liquid crystal compounds of Formulas 1 to 5 may be used one kind or two or more kinds, respectively. Such liquid crystal compositions exhibit good overall physical properties and can exhibit excellent low temperature stability and low rotational viscosity.

Meanwhile, the liquid crystal composition may further include various additives commonly used in the technical field to which the present invention belongs, in addition to the liquid crystal compound. Specifically, the liquid crystal composition may further include an antioxidant. Examples of such antioxidants include antioxidants selected from the group consisting of compounds represented by the following Chemical Formulas (7) and (8).

[Formula 7]

In Formulas 7 and 8, R ¹⁹ and R ²⁰ are each independently hydrogen, oxygen, a radical of any one of alkyl having 1 to 15 carbon atoms, or one or more of -CH ₂ -of the radicals are not directly connected to oxygen atoms. To be substituted with -C≡C_, -CH = CH-, -0-, -COO- or -0C0- or at least one H of said radicals is replaced by halogen,

A ¹³ is cyclonuxylene, tetrahydropyranylene or dioxenylene.

In addition, the liquid crystal composition may further include a UV stabilizer. As such a UV stabilizer, various kinds of UV stabilizers known in the art may be used. Non-limiting, the UV stabilizer may be used Hal s (Hindered amine light stabi l zer) series.

The antioxidant and / or UV stabilizer may be used in an amount of about 1 to 2,000 ppm based on the total weight of the liquid crystal composition. More specifically, the antioxidant and / or UV stabilizer may be used in an amount of about 200 to 500 ppm based on the total weight of the liquid crystal composition. In such a content range, it is possible to secure a stable stability without affecting the overall physical properties of the liquid crystal composition.

The liquid crystal composition according to the embodiment provides a liquid crystal composition having negative dielectric anisotropy. More specifically, the liquid crystal composition may have an absolute value of dielectric anisotropy of 2 or more and 3 or more of black.

The liquid crystal composition according to the embodiment may have a refractive index anisotropy in the range of 0.09 to 0.012. In addition, the liquid crystal composition may exhibit low rotational viscosity within the refractive index anisotropy range. Specifically, the rotational viscosity at 20 ^° C of the liquid crystal composition may be about 90 to 135 mPa-s. The measuring method of the rotational viscosity may refer to the method described in the Examples to be described later. In addition, the liquid crystal composition according to the embodiment is excellent in low temperature stability and It has a high phase transition temperature and can be driven stably in a wide temperature range. Specifically, the liquid crystal composition may have a phase transition temperature from the nematic liquid crystal phase to an isotropic liquid of 70 ^° C. or more and 75 ^° C. or more of black.

The liquid crystal composition may be used for AM-IXlKActive Matrix-LCD (PM-LCD) or Passive Matrix-LCD (PM-LCD), TN (Twist nematic), STN (Super- twisted nematic), VA (Vertical alignment), MVA ( Multi-domain VA (PVA), Patterned VA (PVA), Polymer stabilized VA (PS-VA), Plasma address liquid crystal (PALC), In-lane switching (IPS), Ringe field switching (FFS), Plane line switching (PLS) It can be used in various modes of liquid crystal display such as AH-I PS (Advanced high-performance IPS), ADS (Advanced-super dimensional switching) and PSA (Polymer sustained alignment). In particular, it is expected that the liquid crystal composition according to the embodiment may be applied to the liquid crystal display of the VA mode due to the above-described characteristics, thereby implementing a fast response rate.

On the other hand, according to another embodiment of the invention, there is provided a liquid crystal display comprising the liquid crystal composition described above. The liquid crystal composition may be applied to the liquid crystal display through various methods known in the art. In addition, the liquid crystal display device may be manufactured as a liquid crystal display device of various modes as described above.

A structure according to an embodiment of such a liquid crystal display is shown in FIG. 1. Referring to FIG. 1, the liquid crystal display device 100 includes a color filter substrate 110, a thin film transistor substrate 120, and a liquid crystal layer 130 interposed between the color filter substrate 110 and the thin film transistor substrate 120. ). A plurality of pixel areas is defined on the thin film transistor substrate 120.

The color filter substrate 110 may include an upper base substrate 111, a light blocking layer 112, a color filter 113, an upper organic insulating layer 114, a common electrode 115, and an upper alignment layer 101. . The light blocking layer 112 is formed on the base substrate 111, and may include an opaque material having a low light transmittance, for example, a colorant such as carbon black.

The color filter 113 is formed on the base substrate 111, It may be formed to partially overlap with the light blocking layer 112 or to partially overlap with another adjacent color filter 113. The organic insulating layer 114 protects the light blocking layer 112 and the color filter 113, and compensates for a step generated by the light blocking insect 112 and the color filter 113 to compensate for the color filter substrate. The surface of 110 is planarized.

The common electrode 115 may be made of, for example, indium tin oxide or indium zinc oxide. A predetermined common voltage is applied to the common electrode 115. The upper alignment layer 101 contacts the liquid crystal layer 130 to align or tilt the liquid crystal molecules 131 of the liquid crystal layer 130 in a predetermined direction.

The thin film transistor substrate 120 includes a plurality of thin film transistors. Specifically, the thin film transistor substrate 120 includes a base substrate 121, a gate electrode 122, a gate insulating film 123, a channel layer 124a, an ohmic contact layer 124b, a source electrode 125, and a drain electrode. 126, a passivation layer 127, a lower organic insulating layer 128, a pixel electrode, and a lower alignment layer 102.

The gate electrode 122 is formed on the base substrate 121 and receives a gate signal from a gate Raan (not shown). The gate insulating layer 123 covers the gate electrode 122.

The channel layer 124a is formed on the gate insulating layer 123 so as to overlap the gate electrode 121, and a pair of ohmic contact layers 124b spaced apart from each other are formed on the channel layer 124a.

The source electrode 125 and the drain electrode 126 are formed on the ohmic contact insect 124b. The source electrode 125 and the drain electrode 126 are spaced apart from each other to expose a portion of the channel layer 124a. A portion of the drain electrode 126 is electrically connected to the pixel electrode through the contact hole CH of the lower organic insulating layer 128.

The passivation layer 127 covers the source electrode 125, the drain electrode 126, and the exposed channel layer 124a.

The lower organic insulating layer 128 is formed on the passivation layer 127. The lower organic insulating layer 128 forms a surface of the thin film transistor substrate 120. Flatten.

A contact hole CH is formed in the lower organic insulating layer, through which the drain electrode 126 and the pixel electrode are electrically connected.

The lower organic insulating layer 128 _. A pixel electrode is formed thereon, and a lower alignment layer 102 is formed on the pixel electrode. A predetermined data voltage transferred from the drain electrode 126 is applied to the pixel electrode.

An electric field is generated by a voltage difference between the data voltage and the common voltage applied to the common electrode 115, and thus, the arrangement of the liquid crystal molecules 131 of the liquid crystal layer 130 may be adjusted.

Meanwhile, in order to improve the viewing angle, each pixel may be divided into a plurality of domains so that the liquid crystal composition may be aligned in two or more different directions within one pixel area. In order to divide each pixel into a plurality of domains, protrusions or the like may be formed in each pixel, and the pixel electrode and the common electrode may include a cutout.

The liquid crystal display device according to another exemplary embodiment may be provided by injecting the liquid crystal composition including the liquid crystal compounds of Chemical Formulas 1 and 2 described above into the liquid crystal filling 130. Since the content related to the liquid crystal composition has been described above, a detailed description thereof will be omitted.

The liquid crystal display according to another exemplary embodiment may be implemented in various modes, such as a vertical electric field (for example, TN, STN, and VA) modes, as well as a horizontal electric field (for example, IPS, PLS, and FFS) modes. have. Among these, the liquid crystal display device may be implemented in a VA mode to implement a low threshold voltage and a fast response rate.

【Effects of the Invention】

According to an embodiment of the present invention, the liquid crystal composition may have excellent low temperature stability and high phase transition temperature, and may exhibit low rotational viscosity while showing refractive index anisotropy and dielectric anisotropy. Accordingly, the liquid crystal composition may provide a liquid crystal display device having a low threshold voltage, capable of high speed response and operating in a wide temperature range.

[Brief Description of Drawings]

1 schematically illustrates a structure of a liquid crystal display according to an exemplary embodiment. The figure shown.

[Specific contents to carry out invention]

Hereinafter, the operation and effect of the invention will be described in more detail with reference to specific examples. However, this is presented as an example of the invention, whereby the scope of the invention is not limited in any sense. The physical properties of the liquid crystal composition were evaluated using the method described below.

(1) Low Temperature Stability Evaluation

A 10 mL vial was prepared, and 2 mL of a liquid crystal composition to measure physical properties was injected into the vial. And, the vial containing the liquid crystal composition was observed in the crystallization or phase transition once a day after standing in a warehouse of-25 ^° C. As a result, when the liquid crystal composition maintains the nematic phase after 10 days, it is indicated as 'pass' in Table 2, and when the liquid crystal composition forms crystals or a phase transition occurs within 10 days, The number of days is shown in Table 2.

(2) Phase transition temperature

After dropping the liquid crystal composition to measure the phase transition temperature on the slide glass with a dropper, and covered with a cover glass to prepare a sample.

Place the sample in an instrument with a METTLER TOLEDO FP90 temperature controller,

The FP82HT hot stage was used to increase the temperature at a rate of 3 ^° C / min to observe the change of the sample. The temperature at the point where the sample changes to an isotropic liquid on the nematic liquid crystal phase was recorded, and this operation was repeated three times to derive an average value. And this value was prescribed | regulated as the phase transition temperature () from the nematic liquid crystal phase of a liquid crystal composition to an isotropic liquid.

(3) anisotropy in refraction

The refractive index anisotropy of the liquid crystal composition was measured with an Abbe refractometer equipped with a polarizing plate on the eyepiece using light at a wavelength of 589 nm at 20 ^° C. After rubbing the surface of the main prism in one direction, the liquid crystal composition to be measured is applied to the main prism. It dripped. Then, the refractive index when the direction of polarization is parallel to the direction of rubbing and the refraction when the direction of polarization is perpendicular to the direction of rubbing were measured. The larger refractive index of the two different directions was defined as n _e (extraordinary) and the smaller refractive index was defined as n ₀ (ordinary), and the value obtained by subtracting n ° from n _e was defined as Δη.

(4) dielectric anisotropy

The dielectric anisotropy [Δε] of the liquid crystal composition was calculated by substituting ε ΙΙ and ε 丄 measured in the following manner.

[Equation 1]

Δε = ε II — ε 丄

① Measurement of dielectric constant epsilon ΙΙ: The vertical alignment agent was apply | coated to the surface in which the IT0 pattern of two glass substrates was formed, and the vertical alignment film was formed. Subsequently, spacers were applied to any one of the two glass substrates so that the vertical alignment films faced each other and the gap (cell gap) between the two glass substrates was 4, and then the two glass substrates were bonded together. Then, the liquid crystal composition to be measured is injected into the device and sealed with an adhesive that is cured by heat or ultraviolet rays. The dielectric constant ε ΙΙ was then measured at 20 ^° C of this device using a 4294A instrument manufactured by Agi lent.

(2) Measurement of dielectric constant epsilon [epsilon]: The horizontal alignment agent was apply | coated to the surface in which the ΊΌ pattern of two glass substrates was formed, and the horizontal alignment film was formed. Subsequently, spacers were applied to any one of the two glass substrates such that the horizontal alignment films faced each other and the gap (cell gap) between the two glass substrates was 4, and then the two glass substrates were bonded to each other. The liquid crystal composition to be measured was injected into the mixture, and sealed with an adhesive that was cured with heat or ultraviolet rays. after,

Using a 4294A instrument manufactured by Agi lent, the dielectric constant ε 丄 was measured at 20 ^° C of the device. (5) viscosity and rotational viscosity

SCHOTT CT52 equipment was used to measure the viscosity, and 2 mL of the liquid crystal composition to be measured was injected after mounting a capi lary vi scometer capable of measuring the viscosity of a volume of 2 mL. Thereafter, the liquid crystal composition was stabilized at 20 ^° C. for 30 minutes, and then the liquid crystal composition was pulled up to the measurement site using a dropper louver. Subsequently, the rate at which the liquid crystal composition flows was measured through a timer, and the viscosity was obtained through the timer.

Rotational viscosity measurement

The vertical alignment agent was apply | coated to the surface in which the Ό 'pattern of two glass substrates was formed, and the vertical alignment film was formed. Subsequently, spacers were applied to any one of the two glass substrates so that the vertical alignment films faced each other and the gap (cell gap) between the two glass substrates was 50, and then the two glass substrates were bonded together. And the liquid crystal composition was inject | poured into this element, and it sealed with the adhesive agent hardened by ultraviolet-ray. Then, using a Toyo Corp. Model 6254 equipment equipped with a temperature control ler (Model SU-241) manufactured by ESPEC Corp., the rotational viscosity was measured at 20 ^° C. of the device. Examples and Comparative Examples: Preparation of Liquid Crystal Compositions

EXAMPLES And the liquid crystal compound used by a comparative example is represented by a code | cord | chord. The code is written by sequentially writing the symbols of the ring constituting the center group of the liquid crystal compound from the left side, the linking group connecting the rings of the center group in order, and the terminal group on the right side. At this time, there is no separate mark between the ring group connecting the ring of the central group and the ring of the augmentation group. The individual abbreviations (codes) of the materials are summarized in Table 1 below.

Table 1

Follow-up Link Group Ada Structure Symbol Structure Symbol Structure Symbol Structure Symbol

Referring to Table 1, the following code means a compound having the structure shown below.

According to the composition of Table 2, the liquid crystal compositions of Examples 1 to 6 and Comparative Examples 1 to 4 according to an embodiment of the invention were prepared. And the physical property of the liquid crystal composition was evaluated and shown in Table 2.

0 [Table 2]

BB-3.4 12.00 10.00 11.00 13.00 8.00

BB-3.01 6.50

BB-3. U1 12.00 12.00 12.00 1.00 1.00 13.50 12.00 12.00

BAA— 3. 1 5.00 4.00 7.00 7.00 7.00 7.00 6.00 6.75 7.00 5.00

BAA-3.2 8.00 7.50 7.00 8.00 7.00 7.00 6.00 6.75 7.00 5.00

ANAF-3.02 6.50 5.00 5.00

AF-3.02 14.00 11.00 10.00 11.00 9.00 9.50 8.00 7.50 7.00 9.00

BF-3.02 10.00 10.00 13.00 10.00 13.00 14.50 12.00 13.50 12.00 11.00

BF-5.02 8.00 8.00 8.00 8.00 8.00 8.00 9.00 9.00 8.00 9.00

BBF-2. 1 11.00 11.50 5.00 7.00 5.00 7.00 8.00 9.50 10.00 8.00

BBF-3. 1 5.00 7.00 6.00 7.00 8.00 9.50 10.00 8.00

BBF-3.02 12.00 11.50 12.00 9.00 4.00

BBF-5.02 8.00 7.00 7.00 8.00

BBF-U1.02 16.00 1.00 12.00 12.00 11.50 12.00 12.00 Low temperature pass pass 4 days 1 day pass pass pass pass pass pass stability

evaluation

74.9 75. 1 75.8 76 75. 1 77. 1 75.5 75.6 76.8 76. 1 ᅀ n 0. 1080 0. 1082 0. 1085 0. 1085 0. 1080 0. 1080 0. 1090 0. 1081 0. 1081 0. 1088 n _e 1.5958 1.5955 1.5956 1.5975 1.5950 1.5950 1.5964 1.5951 1.5961 1.5945 n ₀ 1.4878 1.4873 1.4871 1.4890 1.4870 1.4870 1.4874 1.4870 1.4880 1.4857

20.2 21.54 18.96 19.25 19.5 19.99 19.7 18.81 18.92 18.57

[mm ² / s]

-3.4 -3.5 Measurement Measurement -3. 17 -3.44 -3.2 -3.2 -3.0 -3.3 Anisotropy Impossible

Rotational viscosity 140 142 Measurement Measurement 132 131 129 126 125 122 [mPa · s] Not allowed

(In Table 2, the composition unit is weight%.)

Referring to Table 2, ^{7 ′ in} Example 1 according to an embodiment of the present invention. It is confirmed that the liquid crystal composition of 6 exhibits excellent low stability and low rotational viscosity. And it is confirmed that Example 3 and Example 6 which added ANAF-3.02 to Example 2 and Example 5 show lower rotational viscosity.

In contrast, the liquid crystal compositions of Comparative Examples 1 and 2 have BB-3.4 having a structure similar to that of BB-3.U1, which is one of the liquid crystal compounds of Formula 1, and BBF—in which a propenyl group of the liquid crystal compound of Formula 2 is replaced with a propyl group— 3.02, but exhibited a very high rotational viscosity, unlike the liquid crystal compositions of Examples 1-6. In particular, the liquid crystal composition of Comparative Example 3 includes BB-3.U1, which is one of the liquid crystal compounds of Formula 1, and replaces BBF- having a propenyl group substituted with a propyl group instead of the liquid crystal compound BBF-U1.02 of Formula 2 above. Only 3.02 was included but low temperature stability was found to be very weak. In addition, the liquid crystal composition of Comparative Example 4 includes BB-3.U1, which is one of the liquid crystal compounds of Formula 1, and BBF-U1.02, which is one of the liquid crystal compounds of Formula 2, but the content of BBF-U1.02 is It was confirmed that low temperature stability is lower than that of Comparative Example 3, which does not use BBF-U1.02, outside the range of the liquid crystal composition according to the embodiment of the. Accordingly, it was confirmed that both excellent low temperature stability and low rotational viscosity can be obtained through the fine structure difference of the liquid crystal compound, the combination and the composition of the liquid crystal compound.

[Explanation of code]

100: liquid crystal display device

110 ： color filter substrate

120 ： thin film transistor substrate

130: liquid crystal layer

111: upper base substrate

112 ： Light blocking layer

113: color filter

114 ： Upper organic insulating film

115 ： common electrode

101: upper alignment layer

121: base substrate 122: gate electrode 123: gate insulating film 124a: channel charge:

124b: ohmic contact layer 125: source electrode 126: drain electrode 127: passivation layer 128: lower organic insulating film 102: lower alignment film

Claims

[Patent Claims]

[Claim 1]

A liquid crystal composition comprising 1 to 15 parts by weight of the liquid crystal compound represented by the following formula (1) and 1 to 15 parts by weight of the liquid crystal compound represented by the following formula (2) based on 100 parts by weight of the total liquid crystal compound:

In Formula 1, R ¹ is an alkyl group having 1 to 5 carbon atoms,

In Formula 2, R ² is an alkyl group having 1 to 5 carbon atoms.

[Claim 2]

The liquid crystal composition of claim 1, wherein in Formula 1, R ¹ is propyl.

[Claim 3]

The liquid crystal composition of claim 1, wherein R ² in Formula 2 is any one of ethyl, n-propyl, and n-butyl. [Claim 4]

The liquid crystal composition of claim 1, further comprising a liquid crystal compound represented by the following general formula:

In Formula 3, R ²¹ and R ²² are each independently a radical of any one of hydrogen and alkyl having 1 to 15 carbon atoms, or at least one H of the radical increase is substituted with halogen or one or more -CH ₂ -oxygen Atoms Radicals replaced by -C≡C-, -CH = CH-, -0-, -C0-0-, -0-CO- or -0-CO- 0- not directly connected,

A ³ and A ⁴ ring are each independently 1,4-cyclohexylene, tetrahydropyranylene or 1,

4-phenylene.

[Claim 5]

According to claim 4, wherein the liquid crystal compound represented by the formula (3) is of the structure

Wherein R ²¹ and R ²² are each independently a radical of any one of hydrogen and alkyl having 1 to 15 carbon atoms, or at least one H is substituted with halogen, or at least one -CH _2- Radicals replaced by -C≡C-, -CH = CH-, -0-, -C0-0-, -0-CO- or () —CO-0- so as not to be directly connected.

[Claim 6]

The liquid crystal composition of claim 1, further comprising a liquid crystal compound represented by Formula 4 below:

In Formula 4, R ³¹ and R ³² are each independently a radical of any one of hydrogen and alkyl having 1 to 15 carbon atoms, or at least one H is substituted with halogen or at least one -CH ₂ -is oxygen Radicals replaced by -C≡C—, -CH = CH-, -0-, -C0-0-, -0-CO- or-() — C0- 0- so that the atoms are not directly connected,

A ⁵ and A ⁷ ring are each independently 1,4-cyclohexylene, tetrahydropyranylene or 1,4-phenylene,

A ⁶ ring is 1,4-cyclonuylene, tetrahydropyranylene, 1,4-phenylene or At least one H is 1, 4—phenylene substituted with halogen

0 is an integer of 1 or 2.

[Claim 7]

According to claim 6, represented by the formula (4)

[4-8]

Wherein R ³¹ and R ³² are each independently a radical of any one of hydrogen and alkyl having 1 to 15 carbon atoms, or at least one H is substituted with halogen or at least one -CH ₂ -is an oxygen atom. Radicals replaced with -C≡C-, -CH = CH-, -0-, -C0-0-, -0-CO- or-(HXK ⁾ -so that they are not directly linked.

[Claim 8]

The liquid crystal composition of claim 1, further comprising a liquid crystal compound represented by Formula 5 below:

In Formula 5, R ⁴¹ and R ⁴² are each independently hydrogen and carbon number 1 -C≡C-, -CH-CH-, which is a radical of any one of alkyl of 15 to 15, or one or more H of the radicals is substituted with halogen or one or more -CH ₂ -oxygen atoms are not directly connected. Radicals replaced by -0-, -C0-0-, -0-C0- or -0-C0- 0-

m is an integer between 0 and 2.

[Claim 9]

According to claim 8, wherein the liquid crystal compound represented by the formula (5) is of the structure

[5-4]

Wherein R ⁴¹ and R ⁴² are each independently a radical of any one of hydrogen 'and alkyl having 1 to 15 carbon atoms, or at least one H in the radical is substituted with halogen or at least one -CH ₂ -is an oxygen atom Radicals replaced by -C≡C-, -CH = CH-, -0-, -C0-0-, -0-C0- or -OC0-0- so that they are not directly linked.

[Claim 10]

The liquid crystal composition of claim 1, further comprising a liquid crystal compound represented by the following Chemical Formula 6:

In Formula 6, R ⁵¹ and R ⁵² are each independently hydrogen and carbon number 1 A radical of any one of alkyl of 15 to 15, or at least one H of the radicals is substituted with halogen or one or more -CH ₂ -oxygen atoms are not directly connected. Radicals replaced by 0-, -C0-0-, -0-CO- or -0-CO- 0-,

A ¹⁰ , A ¹¹ and A ¹² are each independently 1,4-cyclonuylene, tetrahydropyranylene, 1,4-phenylene or 1,4-phenylene in which at least one H is substituted with halogen,

Z ¹ and Z ² are each independently -CH ₂ CH _2- , -CH = CH-, -C¾0-, -0C¾-, -C≡C-, -CH2CF2-, -CHFCHF-, -CF ₂ CH _2- , -CH ₂ CHF-, -CHFCH _2- , _C ₂ F _4- , -0—, -C00-, -0C0-, -CF ₂ 0- or -0CF _2- ,

nl and n3 are each independently 0 or 1, and the sum of nl and n3 is 1 or

2,

n2 and eta4 are each independently an integer between 0 and 2.

[Claim 11]

The liquid crystal compound of claim 10, wherein the liquid crystal compound represented by Chemical Formula 6 has the following structure:

Wherein R ⁵¹ and R ⁵² are each independently a radical of any one of hydrogen and alkyl having 1 to 15 carbon atoms, or black or at least one H in the radical is substituted with halogen or one or more -CH ₂ -is an oxygen atom Direct Radicals replaced by —C≡C—, —CH═CH—, —0-, —C0-0—, —0-CO— or — (HXK) — so as not to be linked.

[Claim 12]

The liquid crystal composition of claim 1, further comprising a liquid crystal compound represented by Chemical Formula 3, a liquid crystal compound represented by Chemical Formula 4, and a liquid crystal compound represented by Chemical Formula 5.

In Chemical Formulas 3, 4, and 5, R ²¹ , R ²² , R ³¹ , R ³² , R ^41, and R ⁴² are each independently a radical of any one of hydrogen and alkyl having 1 to 15 carbon atoms, or 1 of the radicals. -C≡C_, -CH = CH-, -0-, so that at least H is substituted with halogen or at least one -CH ₂ -oxygen atom is not directly connected

radicals replaced by -co-ο-, -o-co- or -o-co-o-,

A ³ , A ⁴ , A ⁵ and A ⁷ rings are each independently. 1,4-cyclohexylene, tetrahydropyranylene or 1,4 ᅳ phenylene,

A ⁶ , A ⁸ and A ⁹ ring are each independently 1,4-cyclonuylene, tetrahydropyranylene, 1,4-phenylene or 1,4-phenylene in which at least one H is substituted with halogen,

0 is an integer of 1 or 2, and m is an integer between 0 and 2.

[Claim 13] The liquid crystal compound represented by the formula (3) with respect to 100 parts by weight of the total liquid crystal compound, 5 to 40 parts by weight of the liquid crystal compound represented by the formula (4) and 10 to 75 parts by weight of the formula (5) Liquid crystal composition containing a liquid crystal compound represented by.

[Claim 14]

The liquid crystal composition of claim 1, further comprising an antioxidant selected from the group consisting of compounds represented by the following Chemical Formulas 7 and 8:

In Formulas 7 and 8, R ¹⁹ and R ²⁰ are each independently hydrogen, a radical of any one of alkyl having 1 to 15 carbon atoms, or at least one of -C ₂ -oxygen atoms of the radicals is not directly connected to- C≡C— is a radical substituted with -CH = CH-, -0-, -COO- or -0C0- or at least one H of said radicals is replaced by halogen,

A ¹³ is cyclonuxylene, tetrahydropyranylene or dioxenylene.

[Claim 15]

The liquid crystal composition according to claim 1, having negative dielectric anisotropy and having an absolute value of dielectric anisotropy of 2 or more.

[Claim 16]

The liquid crystal composition according to claim 11, wherein the refractive anisotropy is 0.09 to 0.12, and the rotational viscosity at 20 ^° C. is 90 to 135 mPa's.

[Claim 17]

The liquid crystal composition of claim 1, wherein the phase transition temperature is 70 ^° C. or higher. [Claim 18]

A liquid crystal display device comprising the liquid crystal composition according to claim 1. [Claim 19]

19. The liquid crystal display device according to claim 18, wherein the liquid crystal display device adopts a vertical alignment (VA) mode.