KR20170088297A - Liquid crystal composition - Google Patents

Abstract

The present invention relates to a liquid crystal composition suitable for a liquid crystal display device (LCD). Specifically, the present invention provides a liquid crystal composition which comprises a fixed ratio of a compound of positive dielectric anisotropy and a compound of negative dielectric anisotropy, and thus has a high dielectric constant in the short axis direction of liquid crystal, thereby exhibiting very high light transmittance and high brightness while maintaining various parameters obtainable by prior art (broader nematic phase ranges, low viscosity, excellent refractive index anisotropy required according to a phase shift (dn), and high reliability). Thus, the present invention can provide a liquid crystal composition which is applicable to various modes including in-plane switching (IPS), plane to line switching (PLS), fringe field switching (FFS), and advanced super dimension switching (ADS), and thus optimized for liquid crystal display devices.

Description

[0001] Liquid crystal composition [0002]

[0001] The present invention relates to a liquid crystal composition suitable for a liquid crystal display (LCD), and more particularly, to a liquid crystal composition suitable for liquid crystal displays (LCDs), such as in-plane switching (IPS), plane to line switching (PLS), fringe field switching (Advanced super dimension switching) and the like.

Horizontal electric field liquid crystal mode technologies such as IPS (In-plane switching), PLS (Plane to line switching), FFS (Fringe field switching) and ADS (Advanced super dimension switching) Thereby increasing the light transmittance of the liquid crystal panel and improving the contrast ratio and brightness.

However, as the above-mentioned technologies cause the rise of the panel price, the development of such as the reduction of the number of backlights by improving the transmissivity by controlling the characteristics of the liquid crystal is continuing.

The principle of improving the light transmittance in the horizontal electric field liquid crystal mode is as shown in Fig. 1, when a voltage is applied to a cell, the light transmittance increases as the liquid crystal long axis of the upper portion of the pixel electrode is parallel to the substrate. As a result, if the dielectric anisotropy (??) of the liquid crystal used in the horizontal liquid crystal mode is equal, the light transmittance increases as the vertical permittivity (??) Increases.

Such a product with high light transmittance efficiency is continuously required in mobile products such as smart phones, tablets and notebooks, and a liquid crystal composition having a large vertical permittivity value (∈⊥) under the condition of dielectric anisotropy (Δε) Is required.

In general, a liquid crystal mixture having a positive dielectric constant anisotropy consists mainly of a mixture of a single liquid crystal compound having a positive dielectric anisotropy and a single liquid crystal compound having a neutral one.

It is an object of the present invention to provide a liquid crystal mixture to which a specific compound having a positive dielectric anisotropy is added by partially adding a specific compound having a negative dielectric anisotropy to a liquid crystal mixture having stable dielectric properties at room temperature and low temperature, (DELTA epsilon) value relative to the value ([epsilon]), that is, DELTA epsilon / [epsilon].

Another object of the present invention is to provide a liquid crystal display device having a higher light efficiency and thus higher transmittance than a conventional liquid crystal mixture, and a liquid crystal display device of the present invention, in particular a horizontal field mode in-plane switching (IPS) ), FFS (Fringe field switching) and ADS (Advanced super dimension switching) liquid crystal displays.

Another object of the present invention is to provide a liquid crystal display device including the liquid crystal composition.

According to an embodiment of the present invention,

A first component having a positive dielectric anisotropy and containing at least one compound selected from the group of compounds represented by the following formula (1); And

A second component having a negative dielectric anisotropy and containing at least one compound selected from the group of compounds represented by Formula 2 below;

And a liquid crystal composition.

[Chemical Formula 1]

(2)

(In the above Formulas 1 to 2,

R ₁ , R ₂ and R ₃ are independently the same or different and each represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkenyl group having 2 to 4 carbon atoms,

X ₁ to X ₈ are each independently H or F, wherein at least one of X ₅ to X ₈ is F,

Y ₁ is F, OCF ₃ or CF ₃ ,

,

,

,

,

또는

구조 이며,A to D are each independently the same or different,

,

,

,

,

or

Structure,

n, a and b are each independently 0 or 1.)

According to another embodiment of the present invention, there is provided a liquid crystal display device including a liquid crystal composition.

According to the present invention, the dielectric constant in the direction of the short axis of the liquid crystal is large while maintaining various parameters (wide nematic phase range, low viscosity, refractive index anisotropy required according to the retardation (dn), and high reliability) (FP), Fringe field switching (FFS), Advanced super dimension switching (ADS), and the like, by having a very high light transmittance and a high luminance characteristic according to It is possible to provide a liquid crystal composition optimized for a liquid crystal display device. In particular, the present invention can provide a liquid crystal composition more effective for the dielectric constant optimization of 10 to 13, and a liquid crystal composition satisfying such an amount of dielectric anisotropy is excellent in low temperature stability.

Fig. 1 shows the principle of improving the light transmittance when a voltage is applied in the transverse electric field liquid crystal mode.

The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated and described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

If any part is referred to as being "on" another part, it may be directly on the other part or may be accompanied by another part therebetween. In contrast, when referring to a part being "directly above" another part, no other part is interposed therebetween.

The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

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

That is, the alkyl group may be a straight or branched alkyl radical. Specifically, the alkyl group may be methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, or structural isomers thereof.

Hereinafter, the liquid crystal composition of the present invention and the liquid crystal display device including the same will be described in detail.

Liquid crystal composition

A liquid crystal composition according to one embodiment of the present invention comprises a first component having a positive dielectric anisotropy and containing at least one compound selected from the group of compounds represented by the following formula (1); And a second component having at least one negative dielectric anisotropy and at least one compound selected from the group of compounds represented by the following formula (2).

[Chemical Formula 1]

(2)

(In the above Formulas 1 to 2,

R ₁ , R ₂ and R ₃ are independently the same or different and each represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkenyl group having 2 to 4 carbon atoms,

X ₁ to X ₈ are each independently H or F, wherein at least one of X ₅ to X ₈ is F,

Y ₁ is F, OCF ₃ or CF ₃ ,

,

,

,

,

또는

구조 이며,A to D are each independently the same or different,

,

,

,

,

or

Structure,

n, a and b are each independently 0 or 1.)

The present inventors have made efforts to develop a new liquid crystal mixture which can improve the transmittance and satisfy basic liquid crystal properties and has excellent low-temperature stability, as compared with the case of using a liquid crystal mixture of a general component containing mainly positive dielectric anisotropy.

As a result, the present invention relates to a liquid crystal mixture to which a specific compound having a positive dielectric constant anisotropy is added and a specific compound having a negative dielectric anisotropy is further partially added to the liquid crystal mixture, A liquid crystal composition having a small value of dielectric anisotropy (DELTA epsilon) relative to a value (DELTA epsilon), i.e. DELTA epsilon / DELTA epsilon, has been developed.

The liquid crystal composition of the present invention has a positive dielectric anisotropy due to the inclusion of one or more compounds represented by Formula 1, which is a single liquid crystal compound having at least one fluorine group at each of its side and end. In addition, the liquid crystal composition of the present invention has a negative dielectric constant of the formula (2) in which at least one F in the structure is substituted with the formula (1) having the positive dielectric anisotropy, One or more single liquid crystals having anisotropy may be included. In this case, the light transmittance can be improved as compared with the conventional liquid crystal composition having similar dielectric anisotropy.

The liquid crystal composition of the present invention comprises at least one compound of the formula (2) having at least one compound of the formula (1) having a positive dielectric anisotropy as described above and having a negative dielectric anisotropy. Further, according to the first embodiment of the present invention, it is preferable that the liquid crystal composition includes at least one kind of the first component and at least two kinds of the second component. In addition, the liquid crystal composition and the second component, contains two kinds of the second component may be a compound in which R ₃ in the formula (2) having a terminal alkenyl group having 2 to 4 carbon atoms. According to the second embodiment of the present invention, it is preferable that the liquid crystal composition includes two or more kinds of the first component and two or more kinds of the second component. At this time, when two or more kinds of the first component are included, the low temperature stability can be further improved. Particularly, according to the second embodiment, the ratio of the dielectric constant to the vertical value can be reduced while having the high dielectric constant anisotropy of 7 or more.

Specifically, in the liquid crystal composition of the present invention, the compound represented by Formula 1, which is the first component, is a substance that contributes to exhibit low viscosity characteristics while enhancing the dielectric anisotropy of the liquid crystal composition.

Of the CF ₂ O-linking compound known as a material that has a low viscosity and a high dielectric anisotropy in the liquid crystal composition, the compound used in the present invention is a compound having an alkyl group (for example, a methyl group) The solubility of the liquid crystal, particularly at low temperatures, can be increased. And, the compound of formula (1) may have a dielectric anisotropy in an amount of about 20 to 30.

According to one embodiment of the present invention, examples of the first component represented by Formula 1 may be represented by the following Formulas 1-1 to 1-3, but the present invention is not limited thereto.

[화학식 1-1]

[Formula 1-1]

[화학식 1-2]

[Formula 1-2]

[화학식 1-3]

[Formula 1-3]

R1 is the same as defined in formulas (1) to (2).

Further, according to the composition of the first component of the liquid crystal composition of the present invention, the dielectric anisotropy of the entire liquid crystal composition may satisfy at least one of the following conditions:

a) a value of dielectric anisotropy (DELTA epsilon) / permittivity vertical (epsilon) value is less than 3.25 under a condition that the dielectric anisotropy (DELTA epsilon) is 10 or more and less than 13;

(b) a value of dielectric anisotropy (DELTA epsilon) / permittivity vertical ([epsilon]) is 1.90 to 2.75 under the condition that the dielectric anisotropy (DELTA epsilon) is 7 or more and less than 10; or

(c) a value of dielectric anisotropy (DELTA epsilon) / vertical permittivity ([epsilon]) in a range of dielectric anisotropy (DELTA epsilon)

More specifically, the first component may comprise from about 10% to about 50% by weight based on the total weight of the total liquid crystal composition. More suitably, when the total liquid crystal composition has a dielectric anisotropy of 10 or more to less than 13, the first component may be contained in an amount of about 30 to 45% by weight based on the total weight of the entire liquid crystal composition. In addition, when the total liquid crystal composition has a dielectric anisotropy of 7 or more and less than 10, the first component may be contained in an amount of about 25 to 35% by weight based on the total weight of the total liquid crystal composition. In addition, when the liquid crystal composition has a dielectric anisotropy of 4 or more and less than 7, the first component may be included in an amount of about 10 to 25% by weight based on the total weight of the total liquid crystal composition. At this time, it is suitable to optimize the dielectric anisotropy (?) Required to include the first component in the above range.

In addition, in the liquid crystal composition of the present invention, when two or more compounds represented by the formula (1) as the first component are mixed, it is more effective to optimize the dielectric anisotropy to 10 or more to less than 13.

In this case, when the dielectric anisotropy is 10 or more and less than 13, it means that the dielectric anisotropy is equal to or larger than 10 and smaller than 13 (that is, 13 does not include). When the dielectric anisotropy is 7 or more and less than 10, it means that the dielectric anisotropy is equal to or greater than 7 and less than 10 (that is, 10 is not included). When the dielectric anisotropy is 4 or more and less than 7, it means that the dielectric anisotropy is equal to or larger than 4 and smaller than 7 (that is, 7 is not included).

Further, in the case of a liquid crystal mixture having an existing positive dielectric anisotropy, only a mixture of a single liquid crystal compound having a positive dielectric constant anisotropy and a neutral single liquid crystal compound has been limited.

However, the liquid crystal composition of the present invention contains at least one specific compound having a negative dielectric anisotropy of the formula (2) together with the compound having a positive dielectric anisotropy of the formula (1). That is, the present invention includes a negative single liquid crystal of Formula (2) wherein at least one of X ₅ to X ₈ is F and F is substituted at the side of the phenylene structure.

Accordingly, the present invention can significantly lower the dielectric anisotropy (DELTA epsilon) relative to the dielectric constant value ([epsilon]) perpendicular to the direction of the short axis of the liquid crystal at room temperature and low temperature solubility. Therefore, the present invention can provide liquid crystal compositions optimized for various liquid crystal display devices having high luminance and high transmittance.

Particularly, in the present invention, the compound represented by the general formula (2) as the second component contributes to increase the dielectric constant in the short axis direction of the liquid crystal composition. In other words, the compound of Chemical Formula 2 has a large role in reducing the value of ?? / ??. The compound of formula (2) may have a negative dielectric anisotropy of -1 to -7.

Further, according to one embodiment of the present invention, the second component may be included in an amount of about 5 to about 30% by weight based on the total weight of the whole liquid crystal composition. More suitably, the second component can be included in an amount of about 6 to 28% by weight based on the total weight of the total liquid crystal composition.

The present invention relates to a liquid crystal composition having a specific dielectric anisotropy and a dielectric constant anisotropy (Δε) which is higher than that of a conventional liquid crystal composition having a similar dielectric anisotropy, . If the content of Formula 2 contained as the second component is less than 5% by weight, not only the effect of decreasing the value of? /? If it exceeds 30% by weight, the target dielectric anisotropy value of the liquid crystal composition can not be reached.

According to one embodiment of the present invention, examples of the second component represented by Formula 2 may be represented by the following Structures 2-1 to 2-5, but the present invention is not limited thereto.

[화학식 2-1]

[Formula 2-1]

[화학식 2-2]

[Formula 2-2]

[화학식 2-3]

[Formula 2-3]

[화학식 2-4]

[Chemical Formula 2-4]

[화학식 2-5]

[Chemical Formula 2-5]

[화학식 2-6]

[Chemical Formula 2-6]

(Wherein R < ₂ > and R < ₃ > are the same as defined in the above Chemical Formulas 1 and 2)

On the other hand, the liquid crystal composition according to the present invention comprises at least one third component selected from the liquid crystal compounds represented by the following formula (3), at least one fourth component selected from the liquid crystal compounds represented by the following formula (4) And a fourth component.

(3)

(3)

R ₄ and R ₅ are independently the same or different and each represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkenyl group having 2 to 4 carbon atoms,

또는

이며,E and F are each independently the same or different,

or

Lt;

o is 0 or 1.)

[Chemical Formula 4]

(In the formula 4,

R ₆ is an alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkenyl group having 2 to 4 carbon atoms,

X ₉ and X ₁₀ are each independently the same or different and are -H or -F,

Y ₂ is -F, -OCF ₃ or -CF ₃ ,

,

또는

이며,G and H are each independently the same or different,

,

or

Lt;

and m and q are each independently 0 or 1.)

According to an embodiment of the present invention, the third component represented by Formula 3 may be represented by any one of the following Formulas 3-1 to 3-5. The fourth component represented by Formula 4 may be represented by any one of the following Formulas 4-1 to 4-7. However, the present invention is not limited thereto.

[화학식 3-1]

[Formula 3-1]

[화학식 3-2]

[Formula 3-2]

[화학식 3-3]

[Formula 3-3]

[화학식 3-4]

[Chemical Formula 3-4]

[화학식 4-1]

[Formula 4-1]

[화학식 4-2]

[Formula 4-2]

[화학식 4-3]

[Formula 4-3]

[화학식 4-4]

[Formula 4-4]

[화학식 4-5]

[Formula 4-5]

[화학식 4-6]

[Formula 4-6]

[화학식 4-7]

[Formula 4-7]

(Wherein R ₄ to R ₆ have the same meanings as defined in the above formulas (4) and (5)).

According to one embodiment of the present invention, the third component may be included in an amount of about 35 to 65% by weight based on the total weight of the liquid crystal composition. When the third component is further included, it is advantageous to ensure transparency because it is used within the above-mentioned content range.

Further, when two or more of the third components are included, the liquid crystal composition has a low viscosity, which is more effective. In this case, when the liquid crystal composition comprises a third component, at least two kinds of the liquid crystal composition further include at least two kinds, and at least two kinds of compounds included in the third component are those wherein R ₄ is an alkenyl group having 2 to 4 carbon atoms Lt; / RTI >

Further, the fourth component may be included in an amount of about 0 to 20% by weight based on the total weight of the liquid crystal composition. When the fourth component is additionally included, it is necessary to use within the above-mentioned content range to easily control the dielectric anisotropy.

Further, in addition to the liquid crystal composition of the present invention, even when both the third component and the fourth component are included, it is effective to realize the desired dielectric anisotropy.

Meanwhile, according to one embodiment of the present invention, the liquid crystal composition may further include various additives known in the art to which the present invention belongs, if necessary.

For example, the liquid crystal composition may further include at least one additive selected from compounds represented by the following formulas (5) to (8) as an antioxidant.

[Chemical Formula 5]

[Chemical Formula 6]

(7)

[Chemical Formula 8]

(In the above formulas 5 to 8,

R ₇ to R ₁₀ are each independently the same or different and are hydrogen, oxygen, an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms;

q and s are each independently the same or different, and are an integer of 0 to 12, and r is an integer of 1 to 12.)

The additive may be about 1 to about 2,000 ppm, specifically about 200 to about 300 ppm, based on 100 parts by weight of the total liquid crystal composition. When the additive is further included, it should be used within the above-mentioned content range to provide excellent thermal stability.

As described above, the liquid crystal composition of the present invention can be prepared by mixing in a conventional manner, and the method is not limited.

Further, the liquid crystal composition of the present invention may have a nematic upper limit temperature of 70 degrees or higher and a refractive index anisotropy at 20 degrees at 589 nm of 0.09 or more and 0.30 or less.

In particular, the liquid crystal composition of the present invention is characterized in that the dielectric constant vertical value, which is a dielectric constant value (??) Perpendicular to the direction of the short axis of the molecule, is further improved under the condition that the liquid crystal composition has the same dielectric anisotropy. Accordingly, in the present invention, the value of dielectric anisotropy (DELTA epsilon) / vertical permittivity (DELTA epsilon) is lower than that of the conventional one, so that the transmittance can be further increased when a voltage is applied to the liquid crystal panel. That is, the liquid crystal composition of the present invention has a lower dielectric dissipation anisotropy (DELTA epsilon) than the conventional liquid crystal composition having similar dielectric anisotropy (DELTA epsilon / DELTA epsilon) from 0.05 to 0.97 Can be obtained.

According to one embodiment of the present invention, the liquid crystal composition may have a dielectric anisotropy (DELTA epsilon) / permittivity vertical (epsilon) value less than 3.25 under a condition that the dielectric anisotropy (DELTA epsilon) is less than 10 and less than 13, (??) / Vertical permittivity (??) At a condition that the dielectric anisotropy (??) / permittivity vertical (??) Value is 1.90 to 2.75 and the dielectric anisotropy (??) is 4 or more and less than 7 under the condition that the dielectric anisotropy ) Value can be from 1.00 to 1.88.

More preferably, the liquid crystal composition has a dielectric anisotropy (DELTA epsilon) / vertical permittivity (DELTA epsilon) value of 2.50 to 3.25 and a dielectric anisotropy (DELTA epsilon) of 7 or more to 10 Dielectric constant anisotropy (DELTA epsilon) / vertical permittivity (DELTA epsilon) value is in a range of 1.90 to 2.75 and a dielectric anisotropy (DELTA epsilon) is in a range of 4 or more to less than 7 under conditions of a dielectric anisotropy To 1.88.

Liquid crystal display

The liquid crystal composition described above may be incorporated in a liquid crystal layer of various liquid crystal display devices and may be applied to panels including various modes well known in the art. Accordingly, the present invention can be used in the manufacture of various products such as a smart phone, a tablet, and a notebook, thereby improving the light transmittance.

Thus, according to another embodiment of the invention, there is provided a liquid crystal display comprising a liquid crystal composition having the above-described positive dielectric anisotropy. The liquid crystal composition can be applied to a liquid crystal display device through various methods known in the art.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Therefore, in the present invention, the liquid crystal display device is not limited to a great extent, as it is based on a well-known structure in the art, except that the liquid crystal layer including the above-described liquid crystal composition is disposed.

For example, the liquid crystal display device includes a first substrate; A second substrate facing the first substrate; And a liquid crystal layer including a liquid crystal composition having a positive dielectric anisotropy of the present invention disposed between the first substrate and the second substrate. In addition, an electrode region may be formed on one surface of at least one of the first substrate and the second substrate. The electrode includes a common electrode and a pixel electrode.

The liquid crystal display device to which the liquid crystal composition of the present invention is applied may be used in various LCD modes such as a horizontal electric field mode (for example, IPS, PLS, FFS, etc.), but is not limited thereto.

Specifically, the liquid crystal display of the present invention may include a horizontal electric field mode in-plane switching (IPS), a planar to line switching (PLS), a fringe field switching (FFS), or an advanced super dimension switching .

Although the liquid crystal layer including the liquid crystal composition of the present invention does not disclose a specific display device, it can be applied to the manufacture of a liquid crystal display device having a panel including a transverse electric field mode mode as shown in Fig.

Best Mode for Carrying Out the Invention Hereinafter, the function and effect of the present invention will be described in more detail through specific examples of the present invention. It is to be understood, however, that these embodiments are merely illustrative of the invention and are not intended to limit the scope of the invention.

In the examples and comparative examples, the structures of the compounds contained in the liquid crystal composition are respectively divided into a central group, a linking group, and a terminal group, and are represented by symbols as shown in Table 1 below.

Referring to Table 1 above, the following code means the liquid crystal compound having the structure shown below.

AEXE1-3.F:

ACEXE1-3.F:

BB-3.V:

BB-3.U1:

BAF-3.O2:

The physical properties of the liquid crystal compositions prepared in Examples and Comparative Examples were evaluated according to the methods described below. Unless otherwise specified, the properties of the liquid crystal compositions were measured without adding other additives to the liquid crystal compositions prepared in Examples and Comparative Examples.

(1) Transparent point (Tni)

The liquid crystal composition for which the transparent point was to be measured was dropped with a drop on the slide glass with a sphere and covered with a cover glass to prepare a sample for measurement of the transparent point.

The sample was placed in an instrument equipped with a METTLER TOLEDO FP90 temperature regulator and the change in sample was monitored by raising the temperature at a rate of 3 ° C / min with an FP82HT hot stage. The temperature at the point where the hole was formed in the sample was recorded, and this operation was repeated three times to derive an average value. This value was defined as the transparent point of the liquid crystal composition.

(2) Refractive Index Anisotropy (? N)

The refractive index anisotropy (? N) of the liquid crystal composition was measured with an Abbe refractometer equipped with a polarizing plate on an eyepiece using light having a wavelength of 589 nm at 20 ° C. After the surface of the main prism was rubbed in one direction, the liquid crystal composition to be measured was dropped on the main prism. Thereafter, the refractive index (n∥) when the direction of the polarized light was parallel to the rubbing direction and the refractive index (n⊥) when the polarizing direction was perpendicular to the rubbing direction were measured. Then, the refractive index anisotropy (? N) was measured by substituting the refractive index value into the equation (1).

[Formula 1]

? N = n? - n?

(3) Dielectric constant anisotropy (??)

The dielectric anisotropy (?) Of the liquid crystal composition was calculated by substituting the values of?

[Formula 2]

Δε = ε∥ - ε⊥

(1) Measurement of dielectric constant??: A vertical alignment agent was applied to the surface of the two glass substrates on which the ITO pattern was formed to form a vertical alignment film. Subsequently, the spacers were coated on one of the two glass substrates so that the vertical alignment films faced each other and the interval (cell gap) between the two glass substrates was 4 占 퐉, and then the two glass substrates were bonded together. Then, the liquid crystal composition to be measured was poured into the device and sealed with an adhesive which is cured by ultraviolet rays. The dielectric constant ([epsilon]) of the device at 1 kHz, 0.3 V and 20 [deg.] C was then measured using a 4294A instrument manufactured by Agilent.

(2) Measurement of dielectric constant??: A horizontal alignment agent was applied to the surface of the two glass substrates on which the ITO pattern was formed to form a horizontal alignment film. Subsequently, the spacers were coated on one of the two glass substrates so that the horizontal alignment films faced each other and the interval (cell gap) between the two glass substrates was 4 占 퐉, and then the two glass substrates were bonded together. Then, the liquid crystal composition to be measured was poured into the device and sealed with an adhesive which is cured by ultraviolet rays. Thereafter, the dielectric constant (ε⊥) of the device at 1 kHz, 0.3 V, and 20 ° C was measured using a 4294A instrument manufactured by Agilent.

(4) Rotational viscosity (?)

A horizontal alignment agent was applied to the surface of the two glass substrates on which the ITO pattern was formed to form a horizontal alignment film. Then, the spacers were coated on any one of the two glass substrates so that the horizontal alignment films faced each other and the interval (cell gap) between the two glass substrates was 20 占 퐉, and then the two glass substrates were bonded together. Then, a liquid crystal composition was injected into the device, and the device was sealed with an adhesive that cures by ultraviolet rays. The rotational viscosity of the device was then measured at 20 ° C using a Model 6254 instrument from Toyo Corp. equipped with a temperature controller (Model SU-241) manufactured by ESPEC Corp.

(5) Low temperature stability

Each liquid crystal composition was sampled in vials in 2 mL increments and observed for 5 days at an interval of 1 day in a freezer at 30 ° C. In the examples and comparative examples, "5 days OK" was indicated when the nematic phase was maintained for 5 days, and "observation day NG" when smectic or crystallization occurred on the observation day.

< Example  1 to 20 and Comparative Example  1 to 4>

The liquid crystal compositions of Examples 1 to 20 and Comparative Examples 1 to 4 were prepared using liquid crystal compounds having a structure according to the code notation system shown in Table 1 above.

At this time, the following Tables 2 to 4 were compared with liquid crystal compositions having similar dielectric anisotropy, respectively.

Specifically, Table 2 compares the results of Comparative Examples 1 to 2 and Examples 1 to 8 as liquid crystal compositions having a dielectric anisotropy (??) of 10 or more to less than 13.

Table 3 shows liquid crystal compositions having a dielectric anisotropy (DELTA epsilon) of 7 or more and less than 10, and Comparative Example 3 and Examples 9 to 14 were compared and the results were compared.

Table 4 shows liquid crystal compositions having a dielectric anisotropy (DELTA epsilon) of 4 or more and less than 7, and Comparative Examples 4 and 15 to 20 were compared and the results were compared.

division Item Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 1st
ingredient AEXE1-3.F 19.0 11.0 12.0 11.0 12.0 12.0 12.0 12.0 13.0 ACEXE1-2.F 5.0 7.0 3.0 4.0 4.0 4.0 4.0 4.0 ACEXE1-3.F 10.0 11.5 11.5 12.0 11.5 12.0 12.0 12.0 12.0 13.0 IaAEXE1-2.F 6.0 6.0 4.0 5.5 5.0 5.0 5.0 5.0 5.0 IaAEXE1-3.F 6.0 6.0 7.0 5.5 6.0 6.0 6.0 6.0 6.0 Second
ingredient BF-3.O2 3.0 3.0 3.0 3.0 3.0 3.0 BBF-3.O1 2.0 3.0 3.0 BBF-3.O2 2.0 2.0 BBF-5.O2 3.0 BBF-2.1 2.0 2.0 2.0 BAF-3.O2 3.0 2.0 8.0 8.0 8.0 10.0 10.0 AFA-2.3 2.0 2.0 3.0 3.0 3.0 ACA-2.3 3.0 4.0 2.0 2.0 ACA-2.4 2.0 ACA-3.3 2.0 Third
ingredient BB-3.V 24.0 29.0 29.0 39.0 27.0 33.0 33.0 32.0 32.0 34.0 BB-3.U1 4.0 9.0 8.0 8.0 7.0 BBA-V.1 9.0 11.0 10.0 9.0 4.0 5.0 5.0 5.0 3.0 BBA-3.1 3.0 2.0 BAA-3.2 2.0 Fourth
ingredient BAC-3.F 7.0 5.0 3.0 BBE-3.F 8.0 4.0 4.0 5.0 BAE-3.F 8.0 6.5 5.5 3.0 BBA-3.OCF3 5.0 BBCE-3.F 6.0 3.0 3.0 3.0 2.0 3.0 3.0 BBC-V.F 5.0 2.0 2.0 3.0 Low Temperature Stability (LTS) 2 days NG 7 days NG 10 OK 10 OK 10 OK 10 OK 10 OK 10 OK 10 OK 10 OK Transparent point (Tni) 77.3 79.7 79.7 82.3 78.5 81.8 79.0 77.5 78.7 77.1 The refractive index anisotropy (? N) 0.110 0.111 0.111 0.118 0.113 0.120 0.120 0.121 0.121 0.120 Dielectric anisotropy
(? 13.3 12.4 12.2 10.5 12.7 12.4 12.9 12.5 12.4 12.9 The permittivity vertical (ε⊥) 3.8 3.5 3.8 3.4 4.1 4.6 4.7 4.7 4.8 4.7 Δε / ε⊥ 3.50 3.54 3.21 3.09 3.10 2.70 2.74 2.66 2.58 2.63

division Item compare
Example 3 practice
Example 9 practice
Example 10 practice
Example 11 practice
Example 12 practice
Example 13 practice
Example 14 1st
ingredient AEXE1-3.F 11.0 11.0 10.0 11.0 11.0 11.0 11.0 ACEXE1-2.F 6.0 6.0 6.0 7.0 7.0 7.0 8.0 ACEXE1-3.F 10.0 10.0 10.0 12.0 12.0 12.0 12.0 Second
ingredient BF-3.O2 2.0 4.0 4.0 2.0 2.0 BF-5.O2 2.0 3.0 3.0 5.0 6.0 BBF-3.O2 5.0 5.0 5.0 4.0 BBF-2.1 3.0 4.0 BAF-3.O2 3.0 3.0 3.0 5.0 6.0 AFA-2.3 2.0 3.0 3.0 3.0 ACA-2.3 2.0 2.0 Third
ingredient BB-3.V 30.0 30.0 27.5 28.0 28.0 28.0 32.0 BB-3.U1 8.0 8.0 7.0 6.0 6.0 6.0 BBA-V.1 9.0 9.0 8.5 8.0 BBA-3.1 8.0 7.0 8.0 BAA-3.2 6.0 3.0 6.0 BAA-5.2 2.0 Fourth
ingredient BBE-3.F 4.0 4.0 3.0 2.0 3.0 BAE-3.F 7.0 7.0 6.0 2.0 BBA-3.OCF3 7.0 7.0 9.0 9.0 5.0 5.0 BBCE-3.F 2.0 BBC-V.F 3.0 Low Temperature Stability (LTS) 10 OK 10 OK 10 OK 10 OK 10 OK 10 OK 10 OK Transparent point (Tni) 81.7 79.2 79.4 79.0 79.6 81.3 79.1 The refractive index anisotropy (? N) 0.111 0.108 0.112 0.112 0.113 0.112 0.115 The dielectric anisotropy (DELTA epsilon) 9.0 9.3 8.8 8.6 8.6 8.4 8.9 The permittivity vertical (ε⊥) 3.2 3.4 3.5 4.3 4.3 4.3 4.5 Δε / ε⊥ 2.81 2.74 2.51 2.00 2.00 1.95 1.98

division Item compare
Example 4 practice
Example 15 practice
Example 16 practice
Example 17 practice
Example 18 practice
Example 19 practice
Example 20 1st
ingredient AEXE1-3.F 5.0 9.5 10.0 11.0 10.0 ACEXE1-2.F 12.0 5.0 ACEXE1-3.F 11.0 11.0 12.0 12.0 10.0 Second
ingredient BF-3.O2 2.0 3.0 2.0 3.0 3.0 BF-5.O2 3.0 BBF-3.O1 4.0 3.0 4.0 3.0 BBF-3.O2 2.0 3.0 3.0 BBF-2.1 10.0 3.0 BAF-3.O2 6.0 10.0 10.0 4.0 8.0 AFA-2.3 6.0 3.0 4.0 2.0 3.0 3.0 ACA-2.3 4.0 ACA-2.4 ACA-3.3 2.0 Third
ingredient BB-3.V 25.0 39.0 37.0 36.0 35.0 35.0 37.0 BB-3.U1 8.0 8.0 3.0 4.0 5.0 BB-3.4 13.0 BA-3.O2 3.0 2.0 3.0 BBA-V.1 10.5 7.0 2.0 3.0 7.0 BBA-3.1 3.0 3.0 4.0 4.0 BAA-3.2 2.0 2.0 Fourth
ingredient BAC-3.F 13.0 5.5 3.0 2.0 BBE-2.F 7.0 3.0 BBE-3.F 17.0 6.0 2.0 6.0 BAE-3.F 7.0 6.0 3.0 2.0 BBA-3.OCF3 9.0 3.0 BBA-5.OCF3 9.0 BBCE-3.F 3.0 3.5 2.0 BBC-V.F 3.0 10.0 Low Temperature Stability (LTS) 1 day NG 10 OK 10 OK 10 OK 10 OK 10 OK 10 OK Transparent point (Tni) 77.0 78.6 78.1 80.1 77.8 83.1 76.9 Refractive index anisotropy
(? N) 0.098 0.104 0.104 0.107 0.107 0.099 0.117 Dielectric anisotropy
(? 5.4 5.6 6.0 6.4 6.1 4.1 6.2 The permittivity vertical (ε⊥) 2.8 3.0 3.6 4.4 4.1 4.1 4.0 Δε / ε⊥ 1.92 1.87 1.67 1.45 1.49 1.00 1.55

From the results of Tables 2 to 4, it can be seen that the value of ε⊥ (dielectric constant perpendicular to the direction of the short axis of the molecule) in the embodiment of the present invention is larger under the condition of the liquid crystal composition having similar dielectric anisotropy.

Thus, in the embodiment of the present invention, the ratio (?? / ??) of the dielectric anisotropy (??) to the dielectric constant (??) Perpendicular to the direction of the short axis of the liquid crystal is lower than that of the liquid crystal composition having the similar dielectric anisotropy, As a result, when the voltage is applied in the transverse electric field driving panel, the liquid crystal is arranged in parallel with the panel, so that the transmittance can be increased.

However, in the case of the liquid crystal composition having a dielectric anisotropy (DELTA epsilon) of 10 or more to less than 13, Comparative Examples 1 and 2 of Table 2 do not contain the second component of the present invention or are used in a content lower than the range of the present invention, The stability was poor and the ratio of dielectric anisotropy (Δε) to dielectric constant (ε⊥) (Δε / ε⊥) was high.

Further, under the condition that the liquid crystal composition has a dielectric anisotropy (DELTA epsilon) of not less than 7 and less than 10, Comparative Example 3 in Table 3 showed low temperature stability to some extent including the first component, And the value of & quot ; [ Delta] [epsilon] / [ epsilon] "was lower than those of Examples 9 to 14 of the present invention.

And, in Table 4, under the condition that the dielectric anisotropy (? E) is in the range of 4 or more to less than 7, Comparative Example 4 does not include all of the first and second components of the present invention, Direction) and the value of & quot ; [ Delta] [epsilon] / [ epsilon] "are lower than those of Examples 15 to 20. [

Claims (19)

A first component having a positive dielectric anisotropy and containing at least one compound selected from the group of compounds represented by the following formula (1); And
A second component having a negative dielectric anisotropy and containing at least one compound selected from the group of compounds represented by Formula 2 below;
And a positive dielectric anisotropy.
[Chemical Formula 1]

(2)

(In the above Formulas 1 to 2,
R ₁ , R ₂ and R ₃ are independently the same or different and each represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkenyl group having 2 to 4 carbon atoms,
X ₁ to X ₈ are each independently H or F, wherein at least one of X ₅ to X ₈ is F,
Y ₁ is F, OCF ₃ or CF ₃ ,
A to D are each independently the same or different,

,

,

,

,

or

Structure,
n, a and b are each independently 0 or 1.)
The liquid crystal composition according to claim 1, wherein the content of the first component is 10 to 50% by weight based on the total weight of the liquid crystal composition.
The liquid crystal composition according to claim 1, wherein the second component is contained in an amount of 5 to 30% by weight based on the total weight of the liquid crystal composition.
The liquid crystal composition according to claim 1, wherein the liquid crystal composition comprises at least two kinds of first components and at least two kinds of second components.
The liquid crystal composition according to claim 1, which comprises at least two compounds represented by the formula (1) as the first component.
6. The liquid crystal composition according to claim 5, wherein the dielectric anisotropy (DELTA epsilon) satisfies 10 or more to less than 13.
The liquid crystal composition according to claim 1, wherein the dielectric anisotropy of the whole liquid crystal composition satisfies at least one of the following conditions:
a) a value of dielectric anisotropy (DELTA epsilon) / permittivity vertical (epsilon) value is less than 3.25 under a condition that the dielectric anisotropy (DELTA epsilon) is 10 or more and less than 13;
(b) a value of dielectric anisotropy (DELTA epsilon) / permittivity vertical ([epsilon]) is 1.90 to 2.75 under the condition that the dielectric anisotropy (DELTA epsilon) is 7 or more and less than 10; or
(c) a value of dielectric anisotropy (DELTA epsilon) / vertical permittivity ([epsilon]) in a range of dielectric anisotropy (DELTA epsilon)
The liquid crystal composition according to claim 1 or 7, wherein when the total liquid crystal composition has a dielectric anisotropy of 10 or more to less than 13, the first component is contained in an amount of 30 to 45% by weight based on the total weight of the total liquid crystal composition.
The liquid crystal composition according to claim 7, wherein when the total liquid crystal composition has a dielectric anisotropy of 7 or more and less than 10, the first component is contained in an amount of 25 to 35% by weight based on the total weight of the total liquid crystal composition.
The liquid crystal composition according to claim 7, wherein when the total liquid crystal composition has a dielectric anisotropy of 4 or more and less than 7, the first component is contained in an amount of about 10 to 25% by weight based on the total weight of the total liquid crystal composition.
The liquid crystal composition according to claim 1, which comprises at least one third component selected from the liquid crystal compounds represented by the following formula (3), at least one fourth component selected from the liquid crystal compounds represented by the following formula (4) &Lt; / RTI &gt;
(3)

(3)
R ₄ and R ₅ are independently the same or different and each represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkenyl group having 2 to 4 carbon atoms,
E and F are each independently the same or different,

or

Lt;
o is 0 or 1.)
[Chemical Formula 4]

(In the formula 4,
R ₆ is an alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkenyl group having 2 to 4 carbon atoms,
X ₉ and X ₁₀ are each independently the same or different and are -H or -F,
Y ₂ is -F, -OCF ₃ or -CF ₃ ,
G and H are each independently the same or different,

,

or

Lt;
and m and q are each independently 0 or 1.)
12. The method of claim 11, when including the above liquid crystal composition, the third component further comprises at least two or more thereof, wherein the at least two of the R ₄ is seen having 2 to 4 carbon atoms in the formula (3) contained in the third component Or a compound having a carboxyl group.
12. The liquid crystal composition according to claim 11, wherein the third component is contained in an amount of 35 to 65% by weight based on the total weight of the liquid crystal composition.
The liquid crystal composition according to claim 11, wherein the fourth component is contained in an amount of 0 to 20% by weight based on the total weight of the liquid crystal composition.
The liquid crystal composition according to claim 1, further comprising at least one additive selected from compounds represented by the following formulas (5) to (8).
[Chemical Formula 5]

[Chemical Formula 6]

(7)

[Chemical Formula 8]

(In the above formulas 5 to 8,
R ₇ to R ₁₀ are independently the same or different and each is hydrogen, an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms;
q and s are each independently the same or different, and are an integer of 0 to 12, and r is an integer of 1 to 12.)
The liquid crystal composition according to claim 1, wherein the liquid crystal composition is applied to a horizontal electric field mode IPS (In-plane Switching), a Plane to Line Switching (PLS), a Fringe field switching (FFS) or an ADS (Advanced Super Dimension Switching)
A liquid crystal display comprising the liquid crystal composition according to claim 1.
18. The method of claim 17,
A first substrate; A second substrate facing the first substrate; And a liquid crystal layer including a liquid crystal composition having a positive dielectric anisotropy according to claim 1 disposed between the first substrate and the second substrate.
The liquid crystal display according to claim 17 or 18, further comprising: a liquid crystal display (LCD) including a horizontal electric field mode in-plane switching (IPS) mode, a planar to line switching (PLS) mode, a fringe field switching Device.

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