JP2006008928A - Nematic liquid crystal composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal composition for an active matrix-type liquid crystal display element, having a stable nematic phase at a low temperature, while keeping a low refractive index anisotropy of ≤0.08, having a high dielectric anisotropy, and having a low viscosity, and to provide the active matrix-type liquid crystal display element given by using the composition and having a wide operating temperature range. <P>SOLUTION: This liquid crystal composition for the active matrix-type liquid crystal display element contains a compound expressed formula (1) and a compound expressed formula (2). Because the liquid crystal composition for the active matrix-type liquid crystal display element, while keeping the low refractive index anisotropy, has the stable nematic phase at the low temperature, has the high dielectric anisotropy, and has the low viscosity, the composition is useful as a constitutional element for the active matrix-type liquid crystal display element having the wide operating temperature range, and further is very practical for a liquid crystal display of a reflection, semitransparent mode, etc. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a nematic crystal composition useful as an electro-optical liquid crystal display material, and a liquid crystal display device using the same.

  Due to the excellent display quality, active matrix liquid crystal display devices are put on the market for portable terminals, liquid crystal televisions, projectors, computers and the like. In the active matrix display method, TFT (thin film transistor) or MIM (metal insulator metal) is used for each pixel, and high voltage holding ratio is regarded as important for this method. Also, in order to obtain a wider viewing angle characteristic, a TFT display combined with IPS and OCB modes and a reflection type of ECB mode have been proposed to obtain a brighter display. In order to cope with such display elements, new liquid crystal compounds or liquid crystal compositions have been proposed (Patent Document 1 and Patent Document 2).

  In twisted nematic liquid crystal display elements (TN-LCD) and super twisted nematic liquid crystal display elements (STN-LCD), the retarder is the product of the refractive index anisotropy (Δn) of the liquid crystal and the thickness (d) of the liquid crystal medium. The foundation (R; R = Δn · d) is set to a certain value (0.4 to 0.45 is often set for TN-LCD).

  In a reflective or transflective LCD, light enters the liquid crystal medium, reflects off the back reflector, and passes through the liquid crystal medium again, so the actual optical path length is doubled compared to the transmissive LCD. Therefore, in order to obtain the same retardation value, it is necessary to reduce Δn of the liquid crystal medium to about half.

  A low Δn liquid crystal composition can be obtained by increasing the content of a bicyclohexane derivative composed only of a cyclohexane ring having a small Δn value. However, these compounds have high smectic properties, and when the content of the bicyclohexane compound is increased, it is difficult to lower the nematic phase lower limit temperature (Tn), and a liquid crystal composition having a wide nematic temperature range is obtained. It was difficult.

  As a technique for solving some of the above problems, a liquid crystal composition using a cyclohexyldecahydronaphthalene compound and a trifluoro compound has been proposed (Patent Document 3). However, these examples have problems such as Δε is not sufficiently large and the threshold voltage is high, and a liquid crystal composition optimal for the demand for low voltage driving has not been provided.

A liquid crystal composition using a cyclohexyldecahydronaphthalene compound has been proposed as a liquid crystal composition having a small Δn and a large Δε that can be driven at a low voltage (Patent Document 4). In this example, Δε is sufficiently large and the threshold voltage is low, so that a liquid crystal composition optimal for the demand for low voltage driving is provided, but it cannot be said that the viscosity is sufficiently low.
On the other hand, a liquid crystal compound having a dioxane skeleton has already been disclosed (see Patent Document 5). However, the cited document only discloses a wide range of liquid crystal compounds having a dioxane skeleton, and there is no suggestion of the effect of a combination of a dioxane derivative and a specific compound.

  From the above, it has been difficult to obtain a liquid crystal composition having a small Δn, a large Δε that can be driven at a low voltage, and a low viscosity.

JP-A-2-233626 Special Publication 4-501575 Publication JP 2001-354963 A JP 2004-59855 A Special Publication 4-503678

  The problem to be solved by the present invention is to provide a liquid crystal composition for an active matrix liquid crystal display device having a small Δn, a large Δε that can be driven at a low voltage, and a low viscosity. An object of the present invention is to provide an active matrix type liquid crystal display element having a wide operating temperature range.

  As a result of intensive studies to solve the above problems, the present invention has the general formula (1) as the first component,

(In the formula, R ¹ represents an alkyl group having 1 to 15 carbon atoms or an alkenyl group having 2 to 15 carbon atoms, and this group is unsubstituted or has at least one halogen group as a substituent. And one or more of the CH ₂ groups present in these groups are each independently -O-, -S-, -CO-, -COO- , -OCO-, -OCO-O-
Z ¹ is -COO-, -OCO-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -CH ₂ CH _2- , -CF ₂ CF _2- , -CH _{= CH -, - (CH 2} ) 4 -, - CH = CH-CH 2 CH 2 -, - CH 2 CH 2 represents a -CH = CH- or a single bond,
l represents 1 or 2,
Y ¹ represents —OCH ₂ F, —OCHF ₂ , —OCF ₃ or —CF ₃ . ) Containing one or more compounds selected from the group of compounds represented by general formula (2) as a second component,

(式中、R²はR¹と同じ意味を表し、
Z²及びZ³はそれぞれ独立的にZ¹と同じ意味を表し、
m及びnはそれぞれ独立的に0又は1を表し、
Q¹は-OCH₂-、-OCF₂-、-OCHF-、-CF₂-、又は単結合を表し、
X¹〜X³はそれぞれ独立してH、F又はClを表す。)で表される化合物群から選ばれる化合物を1種又は2種以上を含有することを特徴とするアクティブマトリクス型液晶表示素子用液晶組成物を提供する。

(Wherein R ² represents the same meaning as R ¹ ,
Z ² and Z ³ each independently represent the same meaning as Z ¹
m and n each independently represents 0 or 1,
Q ¹ represents -OCH _2- , -OCF _2- , -OCHF-, -CF _2- , or a single bond,
X ^{1 to} X ³ each independently represent H, F or Cl. The liquid crystal composition for an active matrix type liquid crystal display element, comprising one or more compounds selected from the group of compounds represented by formula (1).

  The combination of the liquid crystal compounds of the present invention maintains a low refractive index anisotropy (Δn = 0.05 to 0.08), has a nematic phase stable at low temperature, has a high dielectric anisotropy, and has a low viscosity. A liquid crystal composition for an active matrix type liquid crystal display device was obtained. By using this composition, an active matrix type liquid crystal display element having a wide operating temperature range is provided, which is very practical as a liquid crystal display such as a reflective or transflective mode.

  In the liquid crystal composition of the present invention, the first component contains one or more compounds from the compound group represented by the general formula (1), preferably 1 to 10 types, more preferably 1 to 7 types. Preferably, 1 type-5 types are more preferable.

The content of one or more compounds selected from the compound group represented by the general formula (1) as the first component is preferably in the range of 5 to 30% by mass, and 10 to 20% by mass. More preferably, it is the range. R ¹ is preferably an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, more preferably an unsubstituted linear alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms. Preferably, the structure of the following formulas (a) to (e) is more preferable for the alkenyl group.

(構造式は右端で環に連結しているものとする。)

(The structural formula shall be connected to the ring at the right end.)

Z ¹ is -COO-, -OCO-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -CH ₂ CH _2- , -CF ₂ CF _2- , -CH _{= CH -, - (CH 2} ) 4 -, - CH = CH-CH 2 CH 2 -, - CH 2 CH 2 -CH = CH- , or is a single bond, -COO -, - OCO -, - CH _{2 O -, - OCH 2 -} , - CF 2 O -, - OCF 2 -, - CH 2 CH 2 -, - CF 2 CF 2 -, - CH = CH- or a single bond are preferred, -CF ₂ O- , —OCF ₂ —, —CH ₂ CH ₂ — or a single bond is more preferred, and —CH ₂ CH ₂ — or a single bond is particularly preferred. l is 1 or 2, and 1 is more preferable. Y ¹ is -OCH ₂ F, -OCHF _2, is a -OCF ₃ or -CF _3, preferably -OCF ₃ or -CF _3, -OCF ₃ is more preferable.
More specifically, as a specific structure of the general formula (1), the following general formula (1a)

(式中R¹、Z¹、L¹及びlは一般式(1)におけると同じ意味を表す。)が好ましく、次の化合物が特に好ましい。

(Wherein R ¹ , Z ¹ , L ¹ and l represent the same meaning as in general formula (1)), and the following compounds are particularly preferable.

（式中R¹は、炭素数1〜15のアルキル基、炭素数1〜15のアルコキシル基又は炭素数2〜15のアルケニル基を表す。）

(Wherein R ¹ represents an alkyl group having 1 to 15 carbon atoms, an alkoxyl group having 1 to 15 carbon atoms, or an alkenyl group having 2 to 15 carbon atoms.)

As the second component, it contains one or more from the compound group represented by the general formula (2), preferably 1 to 10 types, more preferably 1 to 5 types, and more preferably 1 to 3 types Is more preferable. The content of one or more compounds selected from the compound group represented by the general formula (2) is preferably in the range of 5 to 25% by mass, and in the range of 5 to 20% by mass. It is more preferable. R ² is preferably an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and an unsubstituted linear alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms. More preferably, in the case of an alkenyl group, structures of the following formulas (a) to (e) are more preferable.

(構造式は右端で環に連結しているものとする。)
Z²、Z³はそれぞれ独立的に、-COO-、-OCO-、-CH₂O-、-OCH₂-、-CF₂O-、-OCF₂-、-CH₂CH₂-、-CF₂CF₂-、-CH=CH-、-(CH₂)₄-、-CH=CH-CH₂CH₂-、-CH₂CH₂-CH=CH- 又は単結合であるが、-COO-、-OCO-、-CH₂O-、-OCH₂-、-CF₂O-、-OCF₂-、-CH₂CH₂-、-CF₂CF₂-、-CH=CH-又は単結合が好ましく、-CF₂O-、-OCF₂-、-CH₂CH₂-又は単結合がより好ましく、-CH₂CH₂-又は単結合が特に好ましい。m、nはそれぞれ独立的に0又は1であるが、m+n=1であることが好ましい。Q¹は-OCH2-、-OCF2-、-OCHF-、-CF2-、又は単結合であるが、-OCF2-、-CF2-、又は単結合が好ましく、単結合がより好ましい。X¹〜X³はそれぞれ独立してH、F又はClであるが、-H又は-Fが好ましく、X²はFが好ましい。
さらに詳述すると、一般式（2）の具体的な構造として以下の一般式(2a)

(The structural formula shall be connected to the ring at the right end.)
Z ² and Z ³ are each independently -COO-, -OCO-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -CH ₂ CH _2- , -CF _{2 CF 2 -, - CH =} CH -, - (CH 2) 4 -, - CH = CH-CH 2 CH 2 -, - CH 2 CH 2 -CH = CH- , or is a single bond, -COO- , -OCO-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -CH ₂ CH _2- , -CF ₂ CF _2- , -CH = CH- or a single bond Preferably, —CF ₂ O—, —OCF ₂ —, —CH ₂ CH ₂ — or a single bond is more preferable, and —CH ₂ CH ₂ — or a single bond is particularly preferable. m and n are each independently 0 or 1, but preferably m + n = 1. Q ¹ is —OCH 2 —, —OCF 2 —, —OCHF—, —CF 2 —, or a single bond, preferably —OCF 2 —, —CF 2 —, or a single bond, and more preferably a single bond. X ^{1 to} X ³ are each independently H, F or Cl, but —H or —F is preferred, and X ² is preferably F.
More specifically, as a specific structure of the general formula (2), the following general formula (2a)

(Wherein R ² , Z ³ and X ³ represent the same meaning as in general formula (2)) are preferred, and the following compounds are particularly preferred.

（式中R²は炭素数1〜15のアルキル基、炭素数1〜15のアルコキシル基又は炭素数2〜15のアルケニル基を表す。）

(Wherein R ² represents an alkyl group having 1 to 15 carbon atoms, an alkoxyl group having 1 to 15 carbon atoms, or an alkenyl group having 2 to 15 carbon atoms.)

  Further improved the compatibility between the compound selected from the compound group represented by the general formula (1) of the first component and the compound selected from the compound group represented by the general formula (2) of the second component, and further stable In order to achieve a nematic phase at low temperature, the general formula (3) or the general formula (4)

(式中、R³〜R⁵はそれぞれ独立的にR¹と同じ意味を表し、
B¹〜B⁵はそれぞれ独立的に
トランス-1,4-シクロへキシレン基(この基中に存在する1個のCH₂基又は隣接していない2個以上のCH₂基は -O- 及び又は -S- に置き換えられてもよい)又は、
1,4-フェニレン基(この基中に存在する1個のCH₂基又は隣接していない2個以上のCH₂基は -N- に置き換えられてもよい)
を表し、芳香環の水素原子はCH₃又はハロゲンで置換されていても良く、
o及びpはそれぞれ独立的に0、1又は2を表し、
L¹〜L⁴はそれぞれ独立的に単結合、-CH₂CH₂-、-(CH₂)₄-、-OCH₂-、-CH₂O-、-COO-、-OCO-、-OCF₂-、-CF₂O-又は-C≡C-を表し、
B¹及びL¹が複数存在する場合はそれらは同一でも良く異なっていても良く、
B⁴及びL³が複数存在する場合はそれらは同一でも良く異なっていても良く、
Q²はQ¹と同じ意味を表し、
X⁴〜X⁶はそれぞれ独立してH、F又はClを表す。)で表される化合物から選ばれる化合物を1種又は2種以上を含有することが好ましい。

(Wherein R ^{3 to} R ⁵ each independently represent the same meaning as R ¹ ,
B ^{1 to} B ⁵ are each independently a trans-1,4-cyclohexylene group (one CH ₂ group present in this group or two or more non-adjacent CH ₂ groups are -O- and Or -S-) or
1,4-phenylene group (one CH ₂ group present in this group or two or more non-adjacent CH ₂ groups may be replaced by -N-)
And the aromatic ring hydrogen atom may be substituted with CH ₃ or halogen,
o and p each independently represent 0, 1 or 2,
L ^{1 to} L ⁴ are each independently a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —COO—, —OCO—, —OCF ₂ -, -CF ₂ O- or -C≡C-
When a plurality of B ¹ and L ¹ are present, they may be the same or different,
When a plurality of B ⁴ and L ³ are present, they may be the same or different,
Q ² has the same meaning as Q ¹
X ^{4 to} X ⁶ each independently represent H, F or Cl. It is preferable to contain one or more compounds selected from the compounds represented by

  It is preferable to contain 2 to 15 types of compound groups represented by general formula (3) or general formula (4) as the third component, more preferably 2 to 10 types, and even more preferably 4 to 7 types. .

The content of one or more compounds selected from the compound group represented by the general formula (3) or the general formula (4) as the third component is more preferably in the range of 5 to 80% by mass. More preferably, it is in the range of 20 to 70% by mass. R ^{3 to} R ⁵ are preferably an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, an unsubstituted linear alkyl group having 1 to 8 carbon atoms or an alkyl group having 2 to 8 carbon atoms. An alkenyl group is more preferable, and the structure of the following formulas (a) to (e) is more preferable as the alkenyl group.

(構造式は右端で環に連結しているものとする。)

(The structural formula shall be connected to the ring at the right end.)

B ^{1 to} B ⁵ are preferably a trans-1,4-cyclohexylene group, 1,4-phenylene group, 3-fluoro-1,4-phenylene group or 3,5-difluoro-1,4-phenylene group, A 1,4-phenylene group or a trans-1,4-cyclohexylene group is more preferred. L ¹ ~L ⁴ is a single _{bond, -CH 2 CH 2 -, -} (CH 2) 4 -, - OCH 2 -, - CH 2 O -, - COO -, - OCO -, - OCF 2 -, - CF ₂ O— or —C≡C—, —COO—, —OCO—, —CH ₂ CH ₂ —, —OCF ₂ —, —CF ₂ O— or a single bond is preferred, —CH ₂ CH ₂ —, —CF ₂ O— or a single bond is more preferable, and —CH ₂ CH ₂ — or a single bond is particularly preferable. o and p are each independently 0, 1 or 2, with 0 or 1 being preferred. Q ² is —OCH ₂ —, —OCF ₂ —, —OCHF—, —CF ₂ —, or a single bond, preferably —OCF ₂ —, —CF ₂ —, or a single bond, and more preferably a single bond. Q ^{4 to} Q ⁶ are preferably —OCF ₂ —, —CF ₂ —, or a single bond, and more preferably a single bond. X ^{4 to} X ⁶ are each independently —H, —F or —Cl, preferably —H or —F, and X ⁵ is preferably —F.

  More specifically, the general formula (3) or the general formula (4) is preferably a compound represented by the following general formula as a specific structure.

（式中R³〜R⁵はそれぞれ独立して、炭素数1〜15のアルキル基、炭素数1〜15のアルコキシル基又は炭素数2〜15のアルケニル基を表す。）
組成物の相溶性をさらに改善し、さらに低電圧化を達成させるために第四成分として一般式(5)

(In the formula, R ^{3 to} R ⁵ each independently represents an alkyl group having 1 to 15 carbon atoms, an alkoxyl group having 1 to 15 carbon atoms, or an alkenyl group having 2 to 15 carbon atoms.)
In order to further improve the compatibility of the composition and achieve a lower voltage, the general formula (5)

(式中、R⁶はR¹と同じ意味を表し、
Z⁴はZ¹と同じ意味を表し、
qはそれぞれ独立的に0又は1を表し、
Q³はQ¹と同じ意味を表し、
X⁷〜X⁹はそれぞれ独立してH、F又はClを表す。)で表される化合物から選ばれる化合物を1種又は2種以上を含有することが好ましい。

(Wherein R ⁶ represents the same meaning as R ¹ ,
Z ⁴ represents the same meaning as Z ¹
q each independently represents 0 or 1,
Q ³ represents the same meaning as Q ¹ ,
X ^{7 to} X ⁹ each independently represent H, F or Cl. It is preferable to contain one or more compounds selected from the compounds represented by

  It is preferable to contain 2-10 types of compound groups represented by General formula (5) as a 4th component, 2-7 types are more preferable, and 5-5 types are further more preferable.

The content of one or more compounds selected from the compound group represented by the general formula (5) as the fourth component is more preferably in the range of 0 to 30% by mass, and 0 to 20% by mass. More preferably, it is the range. R ⁶ is preferably an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and an unsubstituted linear alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms. More preferably, in the case of an alkenyl group, structures of the following formulas (a) to (e) are more preferable.

(構造式は右端で環に連結しているものとする。)

(The structural formula shall be connected to the ring at the right end.)

Z ⁴ is -COO-, -OCO-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -CH ₂ CH _2- , -CF ₂ CF _2- , -CH _{= CH -, - (CH 2} ) 4 -, - CH = CH-CH 2 CH 2 -, - CH 2 CH 2 -CH = CH- , or is a single bond, -COO -, - OCO -, - CH _{2 O -, - OCH 2 -} , - CF 2 O -, - OCF 2 -, - CH 2 CH 2 -, - CF 2 CF 2 -, - CH = CH- or a single bond are preferred, -CF ₂ O- , —OCF ₂ —, —CH ₂ CH ₂ — or a single bond is more preferred, and —CH ₂ CH ₂ — or a single bond is particularly preferred. q is 0 or 1, but is preferably 0. Q ³ is —OCH 2 —, —OCF 2 —, —OCHF—, —CF 2 —, or a single bond, preferably —OCF 2 —, —CF 2 —, or a single bond, and more preferably a single bond. X ^{7 to} X ⁹ are each independently —H, —F or —Cl, preferably —H or —F, and X ⁸ is preferably —F.

More specifically, the general formula (5) is preferably a compound represented by the following general formula as a specific structure.

（式中R⁶は、炭素数1〜15のアルキル基、炭素数1〜15のアルコキシル基又は炭素数2〜15のアルケニル基を表す。）
さらに低電圧化を達成させるために第五成分として一般式(6)

(In the formula, R ⁶ represents an alkyl group having 1 to 15 carbon atoms, an alkoxyl group having 1 to 15 carbon atoms, or an alkenyl group having 2 to 15 carbon atoms.)
In order to achieve further lower voltage, the general formula (6) is used as the fifth component.

(式中、R⁷はR¹と同じ意味を表し、
Z⁵はZ¹と同じ意味を表し、
rはそれぞれ独立的に0又は1を表し、
Q⁴はQ¹と同じ意味を表し、
X¹⁰〜X¹⁴はそれぞれ独立してH、F又はClを表す。)で表される化合物から選ばれる化合物を1種又は2種以上を含有することが好ましい。

(Wherein R ⁷ represents the same meaning as R ¹ ,
Z ⁵ represents the same meaning as Z ¹
each r independently represents 0 or 1,
Q ⁴ represents the same meaning as Q ¹ ,
X ^{10 to} X ¹⁴ each independently represent H, F or Cl. It is preferable to contain one or more compounds selected from the compounds represented by

  It is preferable to contain 2-10 types of compound groups represented by General formula (6) as a 5th component, 2-7 types are more preferable, and 5-5 types are further more preferable.

The content of one or more compounds selected from the compound group represented by the general formula (6) as the fifth component is more preferably in the range of 0 to 30% by mass, and 0 to 20% by mass. More preferably, it is the range. R ⁷ is preferably an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and an unsubstituted linear alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms. More preferably, in the case of an alkenyl group, structures of the following formulas (a) to (e) are more preferable.

(構造式は右端で環に連結しているものとする。)

(The structural formula shall be connected to the ring at the right end.)

Z ⁵ is -COO-, -OCO-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -CH ₂ CH _2- , -CF ₂ CF _2- , -CH _{= CH -, - (CH 2} ) 4 -, - CH = CH-CH 2 CH 2 -, - CH 2 CH 2 -CH = CH- , or is a single bond, -COO -, - OCO -, - CH _{2 O -, - OCH 2 -} , - CF 2 O -, - OCF 2 -, - CH 2 CH 2 -, - CF 2 CF 2 -, - CH = CH- or a single bond are preferred, -CF ₂ O- , —OCF ₂ —, —CH ₂ CH ₂ — or a single bond is more preferred, and —CH ₂ CH ₂ — or a single bond is particularly preferred. r is 0 or 1, but is preferably 0. Q ⁴ is —OCH 2 —, —OCF 2 —, —OCHF—, —CF 2 —, or a single bond, preferably —OCF 2 —, —CF 2 —, or a single bond, and more preferably a single bond. X ^{10 to} X ¹⁴ are each independently H, F or Cl, but —H and —F are preferred, and X ¹³ is preferably F.
More specifically, the general formula (6) is preferably a compound represented by the following general formula as a specific structure.

（式中R⁶は、炭素数1〜15のアルキル基、炭素数1〜15のアルコキシル基又は炭素数2〜15のアルケニル基を表す。）

(In the formula, R ⁶ represents an alkyl group having 1 to 15 carbon atoms, an alkoxyl group having 1 to 15 carbon atoms, or an alkenyl group having 2 to 15 carbon atoms.)

In the present invention, the nematic phase-isotropic liquid phase transition temperature (T _NI ) is more preferably 70 ° C. or higher, and further preferably 80 ° C. or higher. The solid phase or smectic phase-nematic phase transition temperature (T _{→ N} ) is preferably −20 ° C. or lower, and more preferably −30 ° C. or lower. The dielectric anisotropy (Δε) at 25 ° C. is preferably 4.5 to 10.0, and more preferably 5.0 to 8.0. The refractive index anisotropy (Δn) at 25 ° C. is more preferably 0.05 to 0.08, and further preferably 0.06 to 0.07.

The nematic liquid crystal composition is useful for a liquid crystal display element, particularly useful for a liquid crystal display element for driving an active matrix, and can be used for a liquid crystal display element for a reflection mode or a transflective mode.
The nematic liquid crystal composition of the present invention may contain a normal nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal and the like in addition to the above compounds.

  EXAMPLES The present invention will be described in further detail with reference to examples below, but the present invention is not limited to these examples. Further, “%” in the compositions of the following Examples and Comparative Examples means “mass%”.

T _NI : Nematic phase-isotropic liquid phase transition temperature (° C) is the liquid crystal phase upper limit temperature
T _{→ N} : Solid phase or smectic phase-nematic phase transition temperature (° C) is the lower limit of liquid crystal phase temperature
Δε: Dielectric anisotropy Δn: Refractive index anisotropy The following abbreviations are used in the compound description.
Terminal n (number) C _n H _{2n + 1-}
2 -CH ₂ CH _2-
On -OC _n H _{2n + 1}
F -F
CFFF -CF ₃
OCFFF -OCF ₃
ndm- C _n H _{2n + 1} -C = C- (CH ₂ ) _m-1-
nOm- C _n H _{2n + 1} -O- (CH ₂ ) _m-1-
-E- -COO-
-10- -CH ₂ O-
-JO- -CF ₂ O-
-JJ- -CF ₂ CF _2-

(Examples 1 to 3) Preparation of liquid crystal composition Nematic liquid crystal compositions (No. 1), (No. 2) and (No. 3) shown below were prepared, and their physical property values were measured. Shown in 1.

The nematic liquid crystal compositions (No. 1), (No. 2) and (No. 3) of Examples 1 to 3 are characterized by nematic phase-isotropic liquid phase transition temperature (T _NI ), solid phase or smectic phase. -Nematic phase transition temperature (T _{→ N} ), dielectric anisotropy (Δε), refractive index anisotropy (Δn) showed desired values. Also, the viscosity was low and the response speed of the panel was good.

(Comparative Examples 1 to 3) Adjustment of liquid crystal composition As a comparative example, nematic liquid crystal compositions (R1), (R2) and (R3) shown below were adjusted and their physical properties were measured. The results are shown in Table 2. .

The nematic liquid crystal compositions (R1), (R2), and (R3) characteristics of Comparative Examples 1 to 3 have Δn of about 0.06, which is the same as that of Example 2, but Δε is the same as that of the liquid crystal composition No. of Example 2. While 2 is 4.5, the comparative examples are 3.8 to 4.2. This result shows that the liquid crystal composition of the present invention is effective for low voltage driving. The liquid crystal composition No. 3 of Example 3 has Δε of 7.2, which is larger than that of Examples 1 and 2, and is more effective for low voltage driving.

(Comparative Examples 4 to 6) Adjustment of liquid crystal composition As comparative examples, nematic liquid crystal compositions (R4), (R5) and (R6) shown below were adjusted and their physical properties were measured. The results are shown in Table 3. .

The characteristics of the nematic liquid crystal compositions (R4), (R5) and (R6) of Comparative Examples 4 to 6 are as follows: nematic phase-isotropic liquid phase transition temperature (T _NI ), solid phase or smectic phase-nematic phase transition temperature Desirable values were shown in all the characteristics (T 1 _{→ N 2} ), dielectric anisotropy (Δε), and refractive index anisotropy (Δn), but the viscosity was higher than that in Examples.

(Comparative Example 7) Preparation of liquid crystal composition As a comparative example, the nematic liquid crystal composition (R7) shown below was prepared and measured for physical properties. The results are shown in Table 4.

The nematic liquid crystal composition (R7) of Comparative Example 7 has a nematic phase-isotropic liquid phase transition temperature (T _NI ), a solid phase or smectic phase-nematic phase transition temperature (T _{→ N} ), dielectric anisotropy ( Δε), a desired value was shown, but Δn was as high as 0.081, and the desired value was not shown.

Claims (9)

General formula (1) as the first component

(In the formula, R ¹ represents an alkyl group having 1 to 15 carbon atoms or an alkenyl group having 2 to 15 carbon atoms, and this group is unsubstituted or has at least one halogen group as a substituent. And one or more of the CH ₂ groups present in these groups are each independently -O-, -S-, -CO-, -COO- , -OCO-, -OCO-O-
Z ¹ is -COO-, -OCO-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -CH ₂ CH _2- , -CF ₂ CF _2- , -CH _{= CH -, - (CH 2} ) 4 -, - CH = CH-CH 2 CH 2 -, - CH 2 CH 2 represents a -CH = CH- or a single bond,
l represents 1 or 2,
Y ¹ represents —OCH ₂ F, —OCHF ₂ , —OCF ₃ or —CF ₃ . ) Containing one or more compounds represented by formula (2) as a second component,

(Wherein R ² represents the same meaning as R ¹ ,
Z ² and Z ³ each independently represent the same meaning as Z ¹ ,
m and n each independently represents 0 or 1,
Q ¹ represents -OCH _2- , -OCF _2- , -OCHF-, -CF _2- , or a single bond,
X ^{1 to} X ³ each independently represent H, F or Cl. A liquid crystal composition for an active matrix type liquid crystal display device, comprising one or more compounds represented by the formula: Nematic-isotropic transition temperature represents 70 ° C to 120 ° C, crystal or smectic-nematic transition temperature represents -80 ° C to -20 ° C, refractive index anisotropy Δn is 0.05-0.08, dielectric constant anisotropic The liquid crystal composition according to claim 1, wherein the property Δε is 4.5 to 10.0. General formula (3) or general formula (4) as the third component

(Wherein R ^{3 to} R ⁵ each independently represent the same meaning as R ¹ ,
B ^{1 to} B ⁵ are each independently a trans-1,4-cyclohexylene group (one CH ₂ group present in this group or two or more non-adjacent CH ₂ groups are -O- and Or may be replaced by -S-) or
1,4-phenylene group (one CH ₂ group present in this group or two or more non-adjacent CH ₂ groups may be replaced by -N-)
And the aromatic ring hydrogen atom may be substituted with CH ₃ or halogen,
o and p each independently represent 0, 1 or 2,
L ^{1 to} L ⁴ are each independently a single bond, —CH ₂ CH ₂ —, — (CH ₂ ) ₄ —, —OCH ₂ —, —CH ₂ O—, —COO—, —OCO—, —OCF ₂ -, -CF ₂ O- or -C≡C-
When a plurality of B ¹ and L ¹ are present, they may be the same or different,
When a plurality of B ⁴ and L ³ are present, they may be the same or different,
Q ² represents -OCH _2- , -OCF _2- , -OCHF-, -CF _2- , or a single bond,
X ^{4 to} X ⁶ each independently represent H, F or Cl. 3. The liquid crystal composition according to claim 1 or 2, comprising one or more compounds selected from the compounds represented by formula (1). General formula (5) as the fourth component

(Wherein R ⁶ represents the same meaning as R ¹ ,
Z ⁴ represents the same meaning as Z ¹
q each independently represents 0 or 1,
Q ³ represents the same meaning as Q ¹ ,
X ^{7 to} X ⁹ each independently represent H, F or Cl. 4. The liquid crystal composition according to claim 1, comprising one or more compounds selected from the compounds represented by: General formula (6) as the fifth component

(Wherein R ⁷ represents the same meaning as R ¹ ,
Z ⁵ represents the same meaning as Z ¹
each r independently represents 0 or 1,
Q ⁴ represents the same meaning as Q ¹ ,
X ^{10 to} X ¹⁴ each independently represent H, F or Cl. 5. The liquid crystal composition according to claim 1, which comprises one or more compounds selected from compounds represented by: General formula (1) is general formula (1a)

2. The nematic liquid crystal composition according to claim ¹ , wherein R ¹ , Z ¹ , L ¹ and l have the same meaning as in general formula (1). General formula (2) is general formula (2a)

^2. The nematic liquid crystal composition according to claim 1, wherein R ² , Z ³ and X ³ represent the same meaning as in general formula (2). A liquid crystal display device using the nematic liquid crystal composition according to claim 1. An active matrix liquid crystal display device using the nematic liquid crystal composition according to claim 1.