JP5750818B2 - Cholesteric liquid crystal composition for active matrix driving - Google Patents

Description

  The present invention relates to an active matrix driving cholesteric liquid crystal composition useful as an electro-optical liquid crystal display material and a liquid crystal display device using the same.

  A liquid crystal display device using a cholesteric (chiral nematic) liquid crystal composition in which a liquid crystal phase is imparted with a twisted alignment by adding an optically active compound to the liquid crystal composition has bistability, and therefore requires particularly low power consumption. Used in electronic books, electronic price tags, presentation panels, etc. Bistability in cholesteric liquid crystals is achieved by switching between a planar state and a focal conic state by applying a pulse voltage, and the planar and focal conic states are maintained even after the pulse voltage is applied. Sometimes called sex.

  On the other hand, since the display quality is excellent, an active matrix type liquid crystal display device has been put on the market for portable terminals, liquid crystal televisions, projectors, computers and the like. The active matrix display system uses TFT (Thin Film Transistor) or MIM (Metal Insulator Metal) or the like for each pixel, and has become the mainstream of liquid crystal display elements due to its high display quality.

  Since the cholesteric liquid crystal display element has the above-mentioned memory property, conventionally, active matrix driving is not required, and a simple passive matrix driving display element has been used. Since cholesteric liquid crystal display elements by passive matrix driving are inferior in display quality, they do not occupy the mainstream of liquid crystal display elements despite their excellent low power consumption characteristics.

  Active matrix driving of cholesteric liquid crystals has already been disclosed (see Patent Document 1). However, since the cholesteric liquid crystal and the normal nematic liquid crystal have essentially different display principles in the liquid crystal display element, sufficient characteristics cannot be obtained even if the cholesteric liquid crystal for passive matrix driving is used for the active matrix. For example, in a display element using cholesteric liquid crystal, a selective reflection state in a planar state in which the spiral axis is usually perpendicular to the substrate is used. At this time, the half-value width (Δλ) of the selectively reflected light is

It is known that Δn is represented by the refractive index anisotropy of the liquid crystal composition and P is a natural pitch. In order to realize a bright display, a compound having a large refractive index anisotropy is required, but a liquid crystal composition mainly composed of a fluorobenzene compound that is widely used as a nematic liquid crystal composition for driving an active matrix. However, there is a problem that the refractive index anisotropy is small and bright display cannot be realized, and the drive voltage is high (see Patent Documents 2, 4, 5, and 6). In the case of using a liquid crystal composition mainly composed of a cyanobenzene compound which is frequently used for STN, which is a typical driving method of passive matrix driving, the driving voltage is sufficiently low, but it is configured as a display element. In some cases, the image sticking phenomenon cannot be suppressed (see Patent Document 3).

  From the above, when cholesteric liquid crystal is driven in an active matrix, a liquid crystal composition satisfying the required characteristics required for practical use has not been developed, which impedes the practical application of an active matrix driven cholesteric liquid crystal display element. It was.

Japanese Patent Laid-Open No. 7-140440 Japanese Patent No. 3740856 Japanese Patent No. 3765182 JP 2002-285159 A JP 2001-164253 A Japanese National Patent Publication No. 9-506337

  An object of the present invention is to provide a liquid crystal composition that has a high refractive index anisotropy and a low threshold voltage and improves an image sticking phenomenon when an active matrix driving cholesteric liquid crystal display device is configured, and also an image sticking phenomenon is improved. It is an object of the present invention to provide an active matrix drive cholesteric liquid crystal display element having excellent display quality.

  As a result of intensive studies to solve the above problems, the present inventors have found that the problems can be solved by using a cholesteric liquid crystal composition containing a specific fluorine-based liquid crystal compound, a cyanobenzene-based compound, and an optically active compound. The headline of the present invention has been completed.

  The present invention is composed of 2 or 3 6-membered rings, and has a 3,4-difluorobenzene skeleton or a 3,4,5-trifluorobenzene skeleton in the compound, and a refractive index anisotropy of 0.16 to 0. 0. And a compound group A having a dielectric anisotropy of 12 to 30, comprising 2 or 3 6-membered rings, having a cyanobenzene skeleton in the compound, and having a refractive index anisotropy of 0.10. -0.40, the dielectric anisotropy is 10-80, the compound group B is contained, the optically active compound is contained, the content of the compound group A is 50-90%, Provided are an active matrix cholesteric liquid crystal composition having a content of 4 to 30% and an optically active compound content of 0.1 to 5%, and an active matrix cholesteric liquid crystal display device using the liquid crystal composition. .

  The liquid crystal composition of the present invention has a high refractive index anisotropy and a low threshold voltage, and has an excellent effect of improving the image sticking phenomenon when an active matrix drive cholesteric liquid crystal display device is constructed. The liquid crystal composition of the present invention is useful as an active matrix drive cholesteric liquid crystal display element or the like.

  The liquid crystal composition of the present invention comprises a compound group A consisting of 2 or 3 6-membered rings and having a 3,4-difluorobenzene skeleton or a 3,4,5-trifluorobenzene skeleton in the compound. A as general formula (Ia) and general formula (Ib)

(In the formula, R ¹ is an alkyl group having ^{1 to} 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or carbon. An alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 atoms;
A ¹ and A ² are each independently one CH ₂ group or nonadjacent two or more CH ₂ groups may trans-1,4-cyclohexylene be replaced by oxygen atoms present in the radical A hexylene group, or a 1,4-phenylene group in which one carbon atom present in the group or two or more carbon atoms not adjacent to each other may be replaced by a nitrogen atom; The group may be substituted by a methyl group or a fluorine atom,
Z ¹ and Z ² are each independently —CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH ₂ O—, —OCH ₂ —, — CF ₂ O-, -OCF _2- , -COO-, -OCO-, -CH = CH-, -CF = CF-, -C≡C-, -O (CH ₂ ) ₃ -,-(CH ₂ ) ₃ O—, — (CH ₂ ) ₄ — or a single bond, X ¹ represents a hydrogen atom or a fluorine atom,
Y is an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, and 1 to 10 carbon atoms. An alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group or a fluorine atom is represented. It is preferable to use a compound selected from the group consisting of compounds represented by:

In General Formula (Ia) and General Formula (Ib), R ¹ is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or 3 carbon atoms. Preferred is an alkenyloxy group having 10 to 10 carbon atoms or an alkyl group having 1 to 10 carbon atoms substituted with an alkoxy group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms, or an alkyl group having 1 to 8 carbon atoms. More preferred are an alkoxy group, an alkenyl group having 2 to 8 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or an alkyl group having 1 to 8 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms. .

A ¹ is one CH ₂ group or adjacent have not two or more CH ₂ groups cyclohexylene group may trans-1,4-cyclohexylene be replaced by oxygen atoms present in the group, or a methyl group Alternatively, a 1,4-phenylene group which may be substituted by a fluorine atom is preferable. A ² is a group in which one CH ₂ group present in the group or two or more CH ₂ groups which are not adjacent to each other are oxygen atoms. A trans-1,4-cyclohexylene group which may be substituted, or a 1,4-phenylene group which may be substituted by a methyl group or a fluorine atom is preferred, and may be substituted by a methyl group or a fluorine atom A 1,4-phenylene group is more preferred.

Z ¹ is —CF ₂ O—, —OCF ₂ —, —COO—, —OCO—, —CH═CH—, —CF═CF—, —C≡C—, —O (CH ₂ ) ₃ —, -(CH ₂ ) ₃ O-,-(CH ₂ ) ₄ -or a single bond is preferred, -COO-, -OCO-, -C≡C- or a single bond is more preferred, Z ² is -CF ₂ O -, -OCF _2- , -COO-, -OCO-, -CH = CH-, -CF = CF-, -C≡C-, -O (CH ₂ ) ₃ -,-(CH ₂ ) ₃ O- , — (CH ₂ ) ₄ — or a single bond is preferable, —COO—, —OCO—, —C≡C— or a single bond is more preferable, and any one of Z ¹ and Z ² represents a single bond, Preferably represents -C≡C-. X ¹ is preferably a hydrogen atom or a fluorine atom depending on the use, but more preferably a fluorine atom.

  Y is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 10 carbon atoms, or an alkyl group having 1 to 8 carbon atoms. An alkyl group having 1 to 10 carbon atoms substituted with an alkoxy group or a fluorine atom is preferable, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms Further, an alkenyloxy group having 3 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms, or a fluorine atom is more preferable.

  Specific compounds include the following general formula (Ia-a) to general formula (Ia-d), general formula (Ib-a) or general formula (Ib-b)

(In the formula, R ¹ is an alkyl group having ^{1 to} 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or carbon. A compound having a carbon number of 1 to 12 substituted with an alkoxy group of 1 to 10 atoms, and each of X ^{40 to} X ⁶³ independently represents a hydrogen atom or a fluorine atom. preferable.
The compound of the compound group A has a refractive index anisotropy of 0.16 to 0.4, preferably 0.21 or more, more preferably 0.22 or more, and a dielectric anisotropy of 12 to 30. 14 or more, more preferably 15 or more.

Although content of the compound group A is 50 to 90%, 50 to 85% is preferable and 50 to 80% is more preferable.
The refractive index anisotropy and dielectric anisotropy of each compound are defined as follows.
A host liquid crystal having a refractive index anisotropy of 0.102 and a dielectric anisotropy of 4.4 represented by the following composition:

In addition, the refractive index anisotropy and the dielectric anisotropy when 10% of the compound was added were measured, and values extrapolated to 100% from the measurement results were used.
The liquid crystal composition of the present invention contains the compound group B having a refractive index anisotropy of 0.10 to 0.40 and a dielectric anisotropy of 10 to 80. (II)

(In the formula, R ² is an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or carbon. An alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 atoms;
A ³ and A ⁴ are each independently one CH ₂ group or nonadjacent two or more CH ₂ groups may trans-1,4-cyclohexylene be replaced by oxygen atoms present in the radical A hexylene group, or a 1,4-phenylene group in which one carbon atom present in the group or two or more carbon atoms not adjacent to each other may be replaced by a nitrogen atom; The group may be substituted by a fluorine atom,
Z ³ and Z ⁴ are each independently —CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH ₂ O—, —OCH ₂ —, — CF ₂ O-, -OCF _2- , -COO-, -OCO-, -CH = CH-, -CF = CF-, -C≡C-, -O (CH ₂ ) ₃ -,-(CH ₂ ) ₃ O—, — (CH ₂ ) ₄ — or a single bond is represented, and X ² and X ³ each independently represent a hydrogen atom or a fluorine atom. It is preferable to contain the compound represented by this.

In the general formula (II), R ² is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkenyloxy group having 3 to 10 carbon atoms. Or an alkyl group having 1 to 10 carbon atoms substituted with an alkoxy group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or the number of carbon atoms Particularly preferred is an alkyl group having 1 to 8 carbon atoms substituted with an alkenyl group having 2 to 8 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

A ³ is one CH ₂ group or adjacent have not two or more CH ₂ groups cyclohexylene group may trans-1,4-cyclohexylene be replaced by oxygen atoms present in the group, or a methyl group Alternatively, a 1,4-phenylene group which may be substituted with a fluorine atom is preferable.

One CH ₂ group in which A ⁴ is present or two or more CH ₂ groups that are not adjacent to each other may be replaced by an oxygen atom, a trans-1,4-cyclohexylene group, or a methyl group or A 1,4-phenylene group which may be substituted by a fluorine atom is preferred.

Z ³ is —CF ₂ O—, —OCF ₂ —, —COO—, —OCO—, —CH═CH—, —CF═CF—, —C≡C—, —O (CH ₂ ) ₃ —, — (CH ₂ ) ₃ O—, — (CH ₂ ) ₄ — or a single bond is preferable, and —COO—, —OCO—, —C≡C— or a single bond is more preferable.
Z ⁴ is —CF ₂ O—, —OCF ₂ —, —COO—, —OCO—, —CH═CH—, —CF═CF—, —C≡C—, —O (CH ₂ ) ₃ —, — (CH ₂ ) ₃ O—, — (CH ₂ ) ₄ — or a single bond is preferable, and —COO—, —OCO—, —C≡C— or a single bond is more preferable. X ² is preferably a fluorine atom, and X ³ is preferably a fluorine atom.
Specific compounds of the general formula (II) include the following general formulas (II-a) to (II-e)

（式中、Ｒ²は炭素原子数1〜16のアルキル基、炭素原子数1〜16のアルコキシ基、炭素原子数2〜16のアルケニル基、炭素原子数3〜16のアルケニルオキシ基、又は炭素原子数1〜10のアルコキシ基で置換された炭素原子数1〜12のアルキル基を表し、X¹⁰〜X³⁵はそれぞれ独立的に水素原子又はフッ素原子を表す。）で表される化合物が特に好ましい。

(In the formula, R ² is an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or carbon. A compound having a carbon number of 1 to 12 substituted with an alkoxy group of 1 to 10 atoms, and X ^{10 to} X ³⁵ each independently represents a hydrogen atom or a fluorine atom. preferable.

The compound of the compound group B has a refractive index anisotropy of 0.1 to 0.4, preferably 0.13 or more, more preferably 0.15 or more, and a dielectric anisotropy of 10 to 80. 22 or more, more preferably 25 or more.
Although content of the compound group B is 4 to 30%, 5 to 30% is preferable and 5 to 25% is more preferable.
The liquid crystal composition of the present invention preferably further contains a compound group C having a dielectric anisotropy of −1 to 1.
Specifically, as the compound group C, the general formula (III)

（式中、Ｒ³及びＲ⁸はそれぞれ独立して、炭素原子数1〜16のアルキル基、炭素原子数1〜16のアルコキシ基、炭素原子数2〜16のアルケニル基、炭素原子数3〜16のアルケニルオキシ基、又は炭素原子数1〜10のアルコキシ基で置換された炭素原子数1〜12のアルキル基を表し、
Ａ⁵、Ａ⁶、及びＡ⁷はそれぞれ独立して、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基が酸素原子により置き換えられても良いトランス-1,4-シクロへキシレン基、又は基中に存在する1個の炭素原子又は隣接していない2個以上の炭素原子が窒素原子に置き換えられてもよい1,4-フェニレン基を表し、該1,4-フェニレン基はフッ素原子により置換されていても良いが、Ａ⁷は単結合を表していても良い、
Ｚ⁵、及びＺ⁶はそれぞれ独立的して、に-CH₂CH₂-、-CH(CH₃)CH₂-、-CH₂CH(CH₃)-、-CH₂O-、-OCH₂-、-CF₂O-、-OCF₂-、-COO-、-OCO-、-CH=CH-、-CF=CF-、-C≡C-、-O(CH₂)₃-、-(CH₂)₃O-、-(CH₂)₄-又は単結合を表し、pは０、１又は２を表す。）で表される化合物を含有することが好ましい。

Wherein R ³ and R ⁸ are each independently an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, or 3 to 3 carbon atoms. 16 represents an alkenyloxy group or an alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 carbon atoms,
A ^5, A ^6, and A ⁷ each independently are 2 or more CH ₂ groups not one CH ₂ group or adjacent present in groups may be replaced by an oxygen atom trans -1 1,4-cyclohexylene group, or a 1,4-phenylene group in which one carbon atom present in the group or two or more carbon atoms not adjacent to each other may be replaced by a nitrogen atom, , 4-phenylene group may be substituted by a fluorine atom, A ⁷ may represent a single bond,
Z ⁵ and Z ⁶ are each independently —CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH ₂ O—, —OCH ₂ -, -CF ₂ O-, -OCF _2- , -COO-, -OCO-, -CH = CH-, -CF = CF-, -C≡C-, -O (CH ₂ ) ₃ -,-( CH ₂ ) ₃ O—, — (CH ₂ ) ₄ — or a single bond, and p represents 0, 1 or 2. It is preferable to contain the compound represented by this.

In the general formula (III), R ³ and R ⁸ are alkyl groups having 1 to 10 carbon atoms, alkoxy groups having 1 to 10 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, and 3 to 10 carbon atoms. More preferred is an alkenyloxy group or an alkyl group having 1 to 10 carbon atoms substituted with an alkoxy group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. An alkenyl group having 2 to 8 carbon atoms or an alkenyloxy group having 3 to 8 carbon atoms is particularly preferable.
Specifically, the compounds represented by the general formula (III) are represented by the following general formulas (III-a) to (III-u).

Wherein R ⁴ and R ⁵ are each independently an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, or 3 to 3 carbon atoms. A compound selected from the group consisting of 16 alkenyloxy groups and 1-12 alkyl groups substituted with 1-10 carbon atoms is preferred.
The content of the compound group C is preferably 5 to 30%, more preferably 10 to 30%, and particularly preferably 15 to 30%.
The liquid crystal composition of the present invention contains the optically active compound D, but the compound group D is represented by the general formula (IVa) to general formula (IVg).

(Wherein R ⁹ is an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or Represents an alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 carbon atoms, R ¹⁰ represents an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, carbon An alkenyl group having 2 to 16 atoms, an alkenyloxy group having 3 to 16 carbon atoms, an alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 carbon atoms, a hydrogen atom, a fluorine atom, a group One CH ₂ group present in it or two or more CH ₂ groups that are not adjacent to each other may be replaced by an oxygen atom or a trans-1,4-cyclohexylene group or one present in the group 1,4-phenyle in which a carbon atom or two or more non-adjacent carbon atoms may be replaced by a nitrogen atom It represents a group, the 1,4-phenylene group may be substituted by fluorine atoms,
A ^8, A ¹⁰ and A ¹¹ are, one CH ₂ group present in the group or nonadjacent two or more CH ₂ groups replaced also to be trans-1,4-cyclohexylene by an oxygen atom A xylene group or a 1,4-phenylene group in which one carbon atom present in the group or two or more carbon atoms that are not adjacent to each other may be replaced by a nitrogen atom, It may be substituted by a fluorine atom, but A ⁸ , A ¹⁰ and A ¹¹ may represent a single bond, A ⁹ is

を表し、Z⁷、Z⁸、Z⁹及びZ¹⁰はそれぞれ独立的して-CH₂CH₂-、-CH(CH₃)CH₂-、-CH₂CH(CH₃)-、-CH₂O-、-OCH₂-、-CF₂O-、-OCF₂-、-COO-、-OCO-、-CH=CH-、-CF=CF-、-C≡C-、-O(CH₂)₃-、-(CH₂)₃O-、-(CH₂)₄-又は単結合を表す。）で表される化合物を含有することが好ましい。
一般式(IVa)〜一般式(IVf)で表される化合物は具体的には下記の一般式(IVa-a)、一般式(IVb-a)、一般式(IVc-a)、一般式(IVd-a)〜一般式(IVd-c)、一般式(IVe-a)、一般式(IVf-a)又は一般式(IVg-a)

Z ⁷ , Z ⁸ , Z ⁹ and Z ¹⁰ are each independently -CH ₂ CH _2- , -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -COO-, -OCO-, -CH = CH-, -CF = CF-, -C≡C-, -O (CH ₂ ) ₃ -,-(CH ₂ ) ₃ O-,-(CH ₂ ) ₄ -or a single bond. It is preferable to contain the compound represented by this.
Specifically, the compounds represented by the general formula (IVa) to the general formula (IVf) are specifically represented by the following general formula (IVa-a), general formula (IVb-a), general formula (IVc-a), general formula ( IVd-a) to general formula (IVd-c), general formula (IVe-a), general formula (IVf-a) or general formula (IVg-a)

(Wherein R ⁹ is an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or Represents an alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 carbon atoms, R ¹⁰ represents an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, carbon An alkenyl group having 2 to 16 atoms, an alkenyloxy group having 3 to 16 carbon atoms, an alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 carbon atoms, a hydrogen atom, a fluorine atom, a group One CH ₂ group present in it or two or more CH ₂ groups that are not adjacent to each other may be replaced by an oxygen atom or a trans-1,4-cyclohexylene group or one present in the group 1,4-phenyle in which a carbon atom or two or more non-adjacent carbon atoms may be replaced by a nitrogen atom It represents a group, the 1,4-phenylene group may be substituted by fluorine atoms,
A ^8, A ¹⁰ or A ¹¹ are, one CH ₂ group present in the group or nonadjacent two or more CH ₂ groups replaced also to be trans-1,4-cyclohexylene by an oxygen atom A xylene group, or a 1,4-phenylene group in which one carbon atom present in the group or two or more carbon atoms not adjacent to each other may be replaced by a nitrogen atom; May be substituted by a fluorine atom, but A ⁸ , A ¹⁰ or A ¹¹ may represent a single bond,
Z ⁷ , Z ⁸ , Z ⁹ or Z ¹⁰ are each independently -CH ₂ CH _2- , -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH ₂ O- _{, -OCH 2 -, - CF 2} O -, - OCF 2 -, - COO -, - OCO -, - CH = CH -, - CF = CF -, - C≡C -, - O (CH 2) 3 -,-(CH ₂ ) ₃ O-,-(CH ₂ ) ₄ -or a single bond is represented. The compound selected from the compound group represented by this is preferable.

The helical pitch of the liquid crystal composition of the present invention is preferably 130 nm to 1000 nm, more preferably 200 nm to 750 nm, and particularly preferably 300 nm to 700 nm.
When configuring a liquid crystal display element, it is preferable to select so as to reflect light in the visible wavelength range.
The liquid crystal composition of the present invention preferably exhibits a cholesteric phase at -10 ° C to 90 ° C, more preferably -20 ° C to 100 ° C, a lower limit temperature of -40 ° C or lower, and an upper limit temperature of 120 ° C or higher. It is particularly preferred that
The refractive index of the liquid crystal composition is preferably 0.150 or more, and more preferably 0.180 or more. The threshold voltage is preferably 1.7 V or less, and more preferably 1.5 V or less.
The liquid crystal composition of the present invention can contain a stabilizer, an antioxidant, and an antistatic agent as additives, and may contain a polymerizable liquid crystal compound depending on the application.

Hereinafter, although an example is given and this invention is further explained in full detail, this invention is not limited by these. Further, “%” in the compositions of the following examples and comparative examples means “mass%”.
In the examples, the measured characteristics are as follows.
T _NI : Nematic phase-isotropic liquid phase transition temperature (° C)
Δn: birefringence (20 ° C. and 589 nm)
Vth: Drive voltage (25 ° C)
VHR: Voltage holding ratio λ: Selective reflection wavelength (25 ° C) (nm)
IS: Burn-in level Describes more detailed measurement methods
○: Level with no problem after 1000 hours of heating
Δ: Level at which burn-in is confirmed after 1000 hours of heating
X: The following abbreviations are used for the description of the level compound in which seizure is confirmed before reaching 1000 hours of heating.
-Terminal n (number): -C _n H _{2n + 1} ndm-: C _n H _{2n + 1} -CH = CH- (CH ₂ ) _m-1-
-T-: -C≡C- -ndm:-(C _n H _{2n + 1} -CH = CH- (CH ₂ ) _m-1 )
-F: -F -On: -OC _n H _{2n + 1}
-VO-: -COO- -CN: -C≡N
-Z-: -CH = NN = CH- -CF ₂ O-: -CF ₂ -O-

例えば、以下に示すように略号を用いる。

For example, abbreviations are used as shown below.

（実施例1、比較例1、比較例2及び比較例3）
化合物群IとIIの物性値を表1に示す。

(Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3)
The physical properties of compound groups I and II are shown in Table 1.

液晶組成物No.1(実施例1)、液晶組成物M1(比較例1) 、液晶組成物M2(比較例2) 及び液晶組成物M3(比較例3)を調製しこれらの物性値を表2に示す。

Liquid crystal composition No. 1 (Example 1), liquid crystal composition M1 (Comparative Example 1), liquid crystal composition M2 (Comparative Example 2), and liquid crystal composition M3 (Comparative Example 3) were prepared and their physical properties were shown. Shown in 2.

As shown in Table 2, it is clear that the liquid crystal composition of Example 1 has a large difference in image sticking level as compared with Comparative Example 1 and Comparative Example 3. It is clear that Δn and Vth have a large difference between Example 1 and Comparative Example 2. Therefore, it is clear that the liquid crystal composition of the present invention has good display quality such as image sticking and display failure, and can achieve both high birefringence anisotropy and low voltage.
(Example 2, Comparative Example 4 and Comparative Example 5)
Liquid crystal composition No. 2 (Example 2), liquid crystal composition M4 (Comparative Example 4) and liquid crystal composition M5 (Comparative Example 5) were prepared, and their physical properties are shown in Table 3.

  As shown in Table 3, it is clear that the liquid crystal composition of Example 2 has a large difference in image sticking level as compared with Comparative Example 5. Further, when Example 2 and Comparative Example 4 are compared, it is clear that the VHR is the same, but there is a difference in the burn-in level. Therefore, it is clear that the liquid crystal composition of the present invention has good display quality such as image sticking and display failure, and can achieve both high birefringence anisotropy and low voltage.

Claims (9)

2 or 3 6-membered ring, 3,4-difluorobenzene skeleton or 3,4,5-trifluorobenzene skeleton in the compound, refractive index anisotropy is 0.16-0.40 A compound group A comprising at least one compound having a dielectric anisotropy of 12 to 30, a 2 or 3 6-membered ring, a cyanobenzene skeleton in the compound, and a refractive index A compound group B comprising at least one compound having an anisotropy of 0.10 to 0.40 and a dielectric anisotropy of 10 to 80, an optically active compound, Composition for active matrix driving cholesteric liquid crystal display element having a content of 50 to 90%, a content of compound group B of 4 to 30%, and a content of optically active compound of 0.1 to 5% object. The cholesteric liquid crystal composition for driving an active matrix according to claim 1, comprising 5 to 30% of a compound group C having a dielectric anisotropy of -1 to 1. As the compound group A, the general formula (Ia)

(In the formula, R ¹ is an alkyl group having ^{1 to} 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or carbon. An alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 atoms;
A ¹ and A ² are each independently one CH ₂ group or nonadjacent two or more CH ₂ groups may trans-1,4-cyclohexylene be replaced by oxygen atoms present in the radical A hexylene group, or a 1,4-phenylene group in which one carbon atom present in the group or two or more carbon atoms not adjacent to each other may be replaced by a nitrogen atom; The group may be substituted by a methyl group or a fluorine atom,
Z ¹ and Z ² are each independently —CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH ₂ O—, —OCH ₂ —, — CF ₂ O-, -OCF _2- , -COO-, -OCO-, -CH = CH-, -CF = CF-, -C≡C-, -O (CH ₂ ) ₃ -,-(CH ₂ ) _{3 O -, - (CH 2} ) 4 - or a single bond, Table and X ¹ represents a hydrogen atom or a fluorine atom
The The cholesteric liquid crystal composition for driving an active matrix according to claim 1 or 2 , which comprises a compound represented by the formula: 4. The active matrix driving device according to claim 3, wherein in the general formula (Ia), A ² represents a 1,4-phenylene group which may be substituted with a methyl group or a fluorine atom, and Z ² represents —C≡C—. Cholesteric liquid crystal composition. As the compound group B, the general formula (II)

(In the formula, R ² is an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or carbon. An alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 atoms;
A ³ and A ⁴ are each independently one CH ₂ group or nonadjacent two or more CH ₂ groups may trans-1,4-cyclohexylene be replaced by oxygen atoms present in the radical A hexylene group, or a 1,4-phenylene group in which one carbon atom present in the group or two or more carbon atoms not adjacent to each other may be replaced by a nitrogen atom; The group may be substituted by a fluorine atom,
Z ³ and Z ⁴ are each independently —CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH ₂ O—, —OCH ₂ —, — CF ₂ O-, -OCF _2- , -COO-, -OCO-, -CH = CH-, -CF = CF-, -C≡C-, -O (CH ₂ ) ₃ -,-(CH ₂ ) ₃ O—, — (CH ₂ ) ₄ — or a single bond is represented, and X ² and X ³ each independently represent a hydrogen atom or a fluorine atom. A cholesteric liquid crystal composition for driving an active matrix according to claim 1, 2 or 3, which comprises a compound represented by formula (1). 6. A cholesteric liquid crystal composition for driving an active matrix according to claim 5 , wherein in the general formula (II), A ⁴ represents a 1,4-phenylene group which may be substituted with a methyl group or a fluorine atom, and Z ⁴ represents a single bond. object. As the compound group C, the general formula (III)

Wherein R ³ and R ⁸ are each independently an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, or 3 to 3 carbon atoms. 16 represents an alkenyloxy group or an alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 carbon atoms,
A ^5, A ^6, and A ⁷ are each independently, 2 or more CH ₂ groups not one CH ₂ group or adjacent present in groups may be replaced by an oxygen atom trans -1 1,4-cyclohexylene group, or a 1,4-phenylene group in which one carbon atom present in the group or two or more carbon atoms not adjacent to each other may be replaced by a nitrogen atom, , 4-phenylene group may be substituted by a fluorine atom, A ⁷ may represent a single bond,
Z ⁵ and Z ⁶ are each independently —CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH ₂ O—, —OCH ₂ -, -CF ₂ O-, -OCF _2- , -COO-, -OCO-, -CH = CH-, -CF = CF-, -C≡C-, -O (CH ₂ ) ₃ -,-( CH ₂ ) ₃ O—, — (CH ₂ ) ₄ — or a single bond, and p represents 0, 1 or 2. The cholesteric liquid crystal composition for driving an active matrix according to claim 2, which comprises a compound represented by the formula: As optically active compound group D, general formulas (IVa) to (IVg)

(Wherein R ⁹ is an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, an alkenyloxy group having 3 to 16 carbon atoms, or Represents an alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 carbon atoms, R ¹⁰ represents an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, carbon An alkenyl group having 2 to 16 atoms, an alkenyloxy group having 3 to 16 carbon atoms, an alkyl group having 1 to 12 carbon atoms substituted with an alkoxy group having 1 to 10 carbon atoms, a hydrogen atom, a fluorine atom, a group One CH ₂ group present in it or two or more CH ₂ groups that are not adjacent to each other may be replaced by an oxygen atom or a trans-1,4-cyclohexylene group or one present in the group 1,4-phenyle in which a carbon atom or two or more non-adjacent carbon atoms may be replaced by a nitrogen atom It represents a group, the 1,4-phenylene group may be substituted by fluorine atoms,
A ^8, A ¹⁰ and A ¹¹ are, one CH ₂ group present in the group or nonadjacent two or more CH ₂ groups replaced also to be trans-1,4-cyclohexylene by an oxygen atom A xylene group or a 1,4-phenylene group in which one carbon atom present in the group or two or more carbon atoms that are not adjacent to each other may be replaced by a nitrogen atom, It may be substituted by a fluorine atom, but A ⁸ , A ¹⁰ and A ¹¹ may represent a single bond, A ⁹ is

Z ⁷ , Z ⁸ , Z ⁹ and Z ¹⁰ are each independently -CH ₂ CH _2- , -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -COO-, -OCO-, -CH = CH-, -CF = CF-, -C≡C-, -O (CH ₂ ) ₃ -,-(CH ₂ ) ₃ O-,-(CH ₂ ) ₄ -or a single bond. A cholesteric liquid crystal composition for driving an active matrix according to claim 1, 2 or 3, which comprises a compound represented by formula (1). An active matrix cholesteric liquid crystal display element using the cholesteric liquid crystal composition for driving an active matrix according to claim 1.