JP5309645B2 - Polymer-stabilized ferroelectric liquid crystal composition and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer-stabilized ferroelectric liquid crystal composition for reducing driving voltage so as to allow TFT (thin film transistor) drive in a polymer-stabilized ferroelectric liquid crystal display device capable of halftone display, and to provide a polymer-stabilized ferroelectric liquid crystal display device using the liquid crystal display composition and obtaining stable display by TFT drive. <P>SOLUTION: The polymer-stabilized ferroelectric liquid crystal composition comprises a specific polymerizable compound and a liquid crystalline compound represented by formula (II-a), wherein R<SP>11</SP>and R<SP>12</SP>each independently denote a 1-18C linear or branched alkyl group or a fluorine atom; X<SP>11</SP>-X<SP>17</SP>each independently denote a hydrogen atom, a fluorine atom, a CF<SB>3</SB>group or an OCF<SB>3</SB>group; L<SP>11</SP>-L<SP>14</SP>each independently denote a single bond, -O-, -S-, -CO-, -CH<SB>2</SB>O- or the like; and a<SP>1</SP>, b<SP>1</SP>, c<SP>1</SP>and d<SP>1</SP>each independently denote 0 or an integer of 1, provided that a<SP>1</SP>+b<SP>1</SP>+c<SP>1</SP>+d<SP>1</SP>=1, 2 or 3, when a<SP>1</SP>is 0, d<SP>1</SP>is 0, and when a<SP>1</SP>is 1, c<SP>1</SP>is 0. The polymer-stabilized ferroelectric liquid crystal display device using the liquid crystal composition as a constructional element is driven at a low driving voltage, can obtain stable display by TFT drive, capable of halftone display which cannot be achieved by a display device using a single ferroelectric liquid crystal, and has excellent thermal and mechanical stability. The liquid crystal composition is also useful as a structure member of a plastic liquid crystal cell or the like. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a polymer-stabilized ferroelectric liquid crystal composition useful for a polymer-stabilized liquid crystal display element that can be driven by an active element, and a polymer-stabilized liquid crystal display element using the composition.

As a technique for stabilizing liquid crystal alignment using a polymer, a technique for stabilizing the alignment polymer by adding a photocurable monomer to twisted nematic liquid crystal and irradiating with light is disclosed (Non-patent Document 1). reference). The nematic liquid crystal described in the cited document maintains the twisted structure before polymer stabilization even after photocuring, and by using a liquid crystalline monomer having a liquid crystal skeleton as the photocurable monomer, display The liquid crystal properties and orientation of the liquid crystal material are not lost.
The cited document shows an example of a polymer stable type liquid crystal element produced by adding a photocurable monomer to a twisted nematic liquid crystal host at a concentration of several percent and then irradiating with light without applying voltage. . Further, in the examples, voltage-dielectric constant characteristics when the liquid crystal monomer is changed by 2%, 3%, 4%, and 5% are shown. According to this result, when the amount of liquid crystal monomer added increases, the saturation dielectric constant decreases, and a higher voltage needs to be applied in order to saturate, resulting in a higher drive voltage and a corresponding increase in device drive voltage. To do. This is a problem in putting a polymer-stabilized liquid crystal element into practical use.
In addition, when a smectic liquid crystal is used for the liquid crystal element, it behaves fundamentally different from the nematic phase. That is, when the smectic phase is applied as a liquid crystal display element, a phenomenon in which the smectic phase has a layer structure and the major axis (direction of molecules) of liquid crystal molecules is inclined from the direction in which the layer structure is formed is used. The angle at which the liquid crystal molecules are tilted from the normal direction of the layer is called a tilt angle (tilt angle), which is a characteristic property when using smectic liquid crystal as a liquid crystal element, and it is desirable to obtain a tilt angle suitable for the liquid crystal element. The cited document does not disclose the influence on the tilt angle.

  On the other hand, as an example of applying a polymer-stabilized twisted nematic liquid crystal to a TFT liquid crystal display element, a small amount of a photocurable liquid crystalline monomer is added and polymerized in the TFT liquid crystal display element, and alignment is performed by the action of the formed polymer. Has been disclosed (see Patent Document 1). However, in the cited document, although the response speed of the liquid crystal at the time of falling is improved, the problem of the driving voltage described above is not solved, and addition of the photocurable liquid crystal monomer is not performed as described above. There is no disclosure of the effect on the tilt angle.

In addition to the twisted nematic liquid crystal display mode in the polymer-stabilized liquid crystal display element, a technique applied to an OCB (Optically Compensated Birefringence) mode has been proposed (see Non-Patent Document 2). The cited document discloses a technique in which liquid crystal molecules are dispersed in a photoreactive monomer, a desired bend alignment structure is obtained by applying an external electric field, and then the bend alignment is fixed by light irradiation. In the OCB mode, liquid crystal molecules are splayed in the initial state by applying a high voltage when starting up the display device. However, an alignment transition operation is required to change this to a bend alignment. By immobilizing with molecules, it is possible to display in the OCB mode simultaneously with the start-up of the display which does not require the alignment transition operation to the bend arrangement, thereby eliminating the disadvantages of the OCB mode.
In addition, liquid crystal molecules are fixed on a single substrate in a polymer liquid crystal matrix to fix the hybrid alignment, and the two substrates are bonded so that the homogeneous alignment portion on the substrate is in contact with each other to perform OCB mode vent alignment. A technique used for manufacturing liquid crystal display elements is disclosed (see Patent Document 2). In this case, a feature is that a vent orientation is formed without applying a voltage.
However, in the inventions disclosed in these cited references, the problem of the driving voltage described above is not solved, and there is no disclosure about the influence of the addition of the photocurable liquid crystal monomer on the tilt angle.

For polymer-stable ferroelectric liquid crystals (polymer-stable FLC), a technology that uses monomers together with FLC materials to stabilize the polymer by applying an electric field and irradiating ultraviolet rays while aligning the liquid crystal molecules in one direction. Has been proposed (see Non-Patent Documents 3 and 4).
Further, after injecting a liquid crystal composition containing a ferroelectric liquid crystal and a monofunctional liquid crystalline (meth) acrylate monomer into a liquid crystal cell, the composition is irradiated with ultraviolet rays at a temperature at which the composition exhibits a predetermined liquid crystal phase. A polymer-stabilized ferroelectric liquid crystal display device obtained by polymerizing a liquid crystalline (meth) acrylate monomer has been disclosed (see Patent Documents 3, 4 and 5). A new function can be given by stabilizing the alignment of liquid crystal molecules, and the above-mentioned OCB mode and devices using monofunctional liquid crystalline (meth) acrylate for ferroelectric liquid crystal are good vents. Although it has the characteristics of obtaining orientation and good halftone display, the heat resistance of the polymer obtained by polymerization of the monofunctional liquid crystalline (meth) acrylate monomer is not good, resulting in high temperature There was a problem that the reliability was not good. Furthermore, the element using monofunctional liquid crystalline (meth) acrylate as the ferroelectric liquid crystal has a problem that the driving voltage is high. In addition, it is disclosed that a halftone display proportional to the applied voltage can be achieved when the polymer is stabilized by exposure to ultraviolet light in the smectic A phase and then cooled to the smectic C phase and phase-shifted. There was a problem of high. (See Patent Document 3). As described above, even in the inventions disclosed in these cited references, the problem of the driving voltage described above has not been solved, and there has been no disclosure about the influence of the addition of the photocurable liquid crystal monomer on the tilt angle. . Further, since the liquid crystal is 60 to 95% by weight and the remainder is a network polymer, light scattering occurs in the polymer dispersed liquid crystal. This scattering causes the contrast of the display element using polarized light to be lowered. For this reason, there is a drawback that other means are required to improve contrast.
Furthermore, compared with monofunctional liquid crystalline (meth) acrylates, polyfunctional liquid crystalline (meth) acrylates are less likely to interact with low molecular weight liquid crystals, although the thermal fluctuations of mesogenic groups are suppressed and the stability of polymer stabilization is increased. There is also a problem that the operation becomes high and the drive voltage becomes high.

A polymer-stabilized ferroelectric liquid crystal display element using a polyfunctional liquid crystalline monomer that gives a polymer having higher heat resistance than a monofunctional liquid crystalline (meth) acrylate monomer is shown (see Patent Document 6). However, many polyfunctional liquid crystalline monomers have a liquid crystallinity as high as 80 ° C. or higher, and it is necessary to increase the temperature before the irradiation of ultraviolet rays for preparing a polymer-stabilized liquid crystal element. There is a problem that undesirable thermal polymerization is induced and the uniformity of liquid crystal alignment deteriorates.
JP 2005-10202 A JP 2003-248226 A JP-A-9-212462 JP-A-9-21463 Japanese Patent Laid-Open No. 11-21554 JP-A-6-194635 Patent 3771619 Japan Society for the Promotion of Science Information Science Organic Materials 142nd Committee A Section (Liquid Crystal Materials) 91st Research Meeting Materials (pages 28-30) IEICE technical report, Vol. 95, (EID95-17), pp. 43-48, 1995 H. Furue, Japan Journal of Applied Physics, Jpn. J. Appl. Phys., 36, L1517 (1997) H. Furue, Japan Journal of Applied Physics, Jpn. J. Appl. Phys., 37, 3417 (1998)

  An object of the present invention is to provide a polymer-stabilized strong liquid crystal display device capable of reducing driving voltage to a level capable of TFT (thin film transistor) drive in a polymer-stabilized ferroelectric liquid crystal display device capable of halftone display. Provided a dielectric liquid crystal composition, a polymer capable of obtaining a stable display by TFT driving using the polymer-stabilized ferroelectric liquid crystal composition, and capable of obtaining a tilt angle suitable for display The object is to provide a stabilized ferroelectric liquid crystal display device.

In the polymer-stabilized ferroelectric liquid crystal composition, in order to strongly give the liquid crystal molecule the effect of polymer stabilization, a liquid crystalline polymer precursor such as a liquid crystalline acrylate having a mesogenic structure is used as the polymer precursor. Use it. This is because the liquid crystalline acrylate has a mesogenic structure, so it can have a strong anchoring force with the mesogenic structure of the surrounding low-molecular liquid crystal, and therefore the thermal and mechanical stability of the polymer stabilized state Is improved. However, on the other hand, since the anchoring force is increased, the drive voltage is increased, which makes it difficult to drive with an amorphous silicon TFT or a polysilicon TFT. Further, since the anchoring force is increased, the liquid crystal molecules are not easily tilted in the smectic layer, and the tilt angle is reduced.
In order to improve the stability of the polymer stabilized state, a crosslinked polymer may be used using a bifunctional liquid crystalline acrylate or the like. By using bifunctional liquid crystalline acrylates, the mesogenic groups are arranged in the polymer main chain, and both ends of the mesogenic groups are fixed by cross-linking, so there is little influence of thermal fluctuations and the reliability of alignment stabilization of low-molecular liquid crystals Will improve. On the other hand, however, the thermal fluctuation is reduced and the interaction with the low-molecular liquid crystal is increased. As a result, the anchoring force at the low-molecular liquid crystal / polymer interface that occurs when the orientation of the low-molecular liquid crystal is fixed. Further, the driving voltage increases more and more, resulting in a harmful effect. In addition, the liquid crystal molecules are more difficult to tilt in the smectic layer, and the tilt angle is reduced.
To increase the reliability of polymer stabilization, there is a method to increase the cross-linking density of the polymer chain to increase the glass transition temperature, etc., but at the same time the anchoring force between the low-molecular liquid crystal and the polymer increases. As a result, the drive voltage increases and the tilt angle decreases. In addition, increasing the volume ratio of the network polymer chain improves the thermal and mechanical stability of the polymer chain, but the refractive index of the polymer chain affects the refractive index distribution of the low-molecular liquid crystal in the display element. The contrast of the display is lowered by causing light scattering due to the difference in refractive index with the low-molecular liquid crystal.

When the liquid crystalline polymer precursor is used in this manner, the polymer stabilization state is stabilized, but at the same time, the anchoring force increases, causing an undesirable increase in driving voltage and a decrease in tilt angle. However, the inventors of the present application have studied the composition of various polymerizable liquid crystal compounds and liquid crystal compounds, and as a result, studied the simultaneous use of both liquid crystalline polymer precursors and non-liquid crystalline polymer precursors. The inventors have found that the increase of the drive voltage and the decrease of the tilt angle are prevented, and further, the temperature dependency of the drive voltage is suppressed, and the present invention has been completed.
The present application relates to the general formula (Ia)

（式（Ｉ−ａ）中、Ａ^１は水素原子又はメチル基を表し、
Ａ^２は単結合又は炭素原子数１から１５のアルキレン基（該アルキレン基中に存在する１個又は２個以上のメチレン基は、酸素原子が相互に直接結合しないものとして、それぞれ独立に酸素原子、−ＣＯ−、−ＣＯＯ−又は−ＯＣＯ−で置換されていても良く、該アルキレン基中に存在する１個又は２個以上の水素原子はそれぞれ独立にフッ素原子、メチル基又はエチル基で置換されていても良い。）を表し、
Ａ^３及びＡ^６はそれぞれ独立して水素原子又は炭素原子数１から１８のアルキル基（該アルキル基中に存在する１個又は２個以上のメチレン基は、酸素原子が相互に直接結合しないものとしてそれぞれ独立に酸素原子、−ＣＯ−、−ＣＯＯ−又は−ＯＣＯ−で置換されていても良く、該アルキル基中に存在する１個又は２個以上の水素原子はそれぞれ独立にハロゲン原子又は炭素原子数１から１７のアルキル基で置換されていても良い。）を表し、
Ａ^４及びＡ^７はそれぞれ独立して水素原子又は炭素原子数１から１０のアルキル基（該アルキル基中に存在する１個又は２個以上のメチレン基は酸素原子が相互に直接結合しないものとしてそれぞれ独立に酸素原子、−ＣＯ−、−ＣＯＯ−又は−ＯＣＯ−で置換されていても良く、該アルキル基中に存在する１個又は２個以上の水素原子はそれぞれ独立にハロゲン原子又は炭素原子数１から９のアルキル基で置換されていても良い。）を表し、
ｋは１から４０を表し、
Ｂ^１、Ｂ^２及びＢ^３は、それぞれ独立して水素原子、炭素原子数１から１０の直鎖もしくは分岐のアルキル基（該アルキル基中に存在する１個もしくは２個以上のメチレン基は、酸素原子が相互に直接結合しないものとしてそれぞれ独立に酸素原子、−ＣＯ−、−ＣＯＯ−又は−ＯＣＯ−で置換されていても良い）、又は一般式（Ｉ−ｂ）

(In the formula (Ia), A ¹ represents a hydrogen atom or a methyl group,
A ² represents a single bond or an alkylene group having 1 to 15 carbon atoms (one or two or more methylene groups present in the alkylene group are each independently an oxygen atom on the assumption that oxygen atoms are not directly bonded to each other). , —CO—, —COO— or —OCO— may be substituted, and one or two or more hydrogen atoms present in the alkylene group are each independently substituted with a fluorine atom, a methyl group or an ethyl group May be)
A ³ and A ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 18 carbon atoms (one or two or more methylene groups present in the alkyl group are such that oxygen atoms are not directly bonded to each other) Each independently may be substituted with an oxygen atom, -CO-, -COO- or -OCO-, and one or more hydrogen atoms present in the alkyl group are each independently a halogen atom or carbon. Which may be substituted with an alkyl group of 1 to 17 atoms).
A ⁴ and A ⁷ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (one or two or more methylene groups present in the alkyl group are such that oxygen atoms are not directly bonded to each other). Each independently substituted with an oxygen atom, -CO-, -COO- or -OCO-, and one or more hydrogen atoms present in the alkyl group are each independently a halogen atom or a carbon atom. Which may be substituted with an alkyl group of the formula 1 to 9),
k represents 1 to 40;
B ¹ , B ² and B ³ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms (one or two or more methylene groups present in the alkyl group are The oxygen atoms may be independently substituted with oxygen atoms, —CO—, —COO—, or —OCO— as those in which oxygen atoms are not directly bonded to each other), or the general formula (Ib)

（式（Ｉ−ｂ）中、Ａ^９は水素原子又はメチル基を表し、
Ａ^８は単結合又は炭素原子数１から１５のアルキレン基（該アルキレン基中に存在する１個又は２個以上のメチレン基は、酸素原子が相互に直接結合しないものとして、それぞれ独立に酸素原子、−ＣＯ−、−ＣＯＯ−又は−ＯＣＯ−で置換されていても良く、該アルキレン基中に存在する１個又は２個以上の水素原子はそれぞれ独立にフッ素原子、メチル基又はエチル基で置換されていても良い。）で表される基を表す。ただし、２k＋１個あるＢ^１、Ｂ^２及びＢ^３のうち前記一般式（Ｉ−ｂ）で表される基となるものの個数は０〜３個である。）
で表される重合性化合物であって、該重合性化合物の重合物のガラス転移温度が−１００℃から２５℃である重合性化合物（Ｉ）と、一般式（ＩＩ）

(In formula (Ib), A ⁹ represents a hydrogen atom or a methyl group,
A ⁸ is a single bond or an alkylene group having 1 to 15 carbon atoms (one or two or more methylene groups present in the alkylene group are each independently an oxygen atom, assuming that oxygen atoms are not directly bonded to each other). , —CO—, —COO— or —OCO— may be substituted, and one or two or more hydrogen atoms present in the alkylene group are each independently substituted with a fluorine atom, a methyl group or an ethyl group Represents a group represented by: However, the number of the groups represented by the general formula (Ib) among B ¹ , B ^2, and B ³ that are 2k + 1 is 0 to 3. )
A polymerizable compound (I) having a glass transition temperature of −100 ° C. to 25 ° C. of the polymerized polymer of the polymerizable compound, and a general formula (II)

（式中、Ｒ^１１及びＲ^１２は各々独立に炭素原子数１〜１８の直鎖状又は分岐状のアルキル基あるいはフッ素原子を示し、但し、Ｒ１１とＲ１２が同時にフッ素原子となることはなく、さらに、１つ又は２つの隣接していない−ＣＨ_２−基が−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯ−Ｏ−、−Ｏ−ＣＯ−、−ＣＯ−Ｓ−、−Ｓ−ＣＯ−、−Ｏ−ＣＯ−Ｏ−、−ＣＨ＝ＣＨ−、−Ｃ≡Ｃ−、シクロプロピレン基又は−Ｓｉ（ＣＨ_３）_２−で置き換えられてもよく、さらにアルキル基の１つ又はそれ以上の水素原子がフッ素原子あるいはＣＮ基で置き換えられていてもよく、Ｘ^１１〜Ｘ^１７は各々独立に水素原子、フッ素原子、ＣＦ_３基、あるいはＯＣＦ_３基を示し、Ｌ^１１、Ｌ^１２、Ｌ^１３、Ｌ^１４は各々独立に単結合、−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、−ＣＯ−Ｏ−、−Ｏ−ＣＯ−、−ＣＯ−Ｓ−、−Ｓ−ＣＯ−、−Ｏ−ＣＯ−Ｏ−、−ＣＨ_２ＣＨ_２−、−ＣＨ＝ＣＨ−、−Ｃ≡Ｃ−であり、ａ^１、ｂ^１、ｃ^１、ｄ^１は各々独立に０又は１の整数を示し、但し、ａ^１＋ｂ^１＋ｃ^１＋ｄ^１は１、２又は３であり、ａ^１が０の場合はｄ^１は０であり、ａ^１が１の場合はｃ^１は０である。）
で表される液晶性化合物（ＩＩ）と、一般式（ＩＩＩ−ａ）

(Wherein R ¹¹ and R ¹² each independently represent a linear or branched alkyl group having 1 to 18 carbon atoms or a fluorine atom, provided that R 11 and R 12 do not simultaneously become a fluorine atom, Furthermore, one or two non-adjacent —CH ₂ — groups are —O—, —S—, —CO—, —CO—O—, —O—CO—, —CO—S—, —S—. CO—, —O—CO—O—, —CH═CH—, —C≡C—, a cyclopropylene group or —Si (CH ₃ ) ₂ — may be substituted, and one or more alkyl groups may be substituted. The above hydrogen atoms may be replaced by fluorine atoms or CN groups, and X ^{11 to} X ¹⁷ each independently represent a hydrogen atom, a fluorine atom, a CF ₃ group, or an OCF ₃ group, and L ¹¹ , L ¹² , L ^{13, L 14} are each independently a single bond, -O -, - _{-, - CO -, - CH} 2 O -, - OCH 2 -, - CF 2 O -, - OCF 2 -, - CO-O -, - O-CO -, - CO-S -, - S-CO —, —O—CO—O—, —CH ₂ CH ₂ —, —CH═CH—, —C≡C—, and each of a ¹ , b ¹ , c ¹ and d ¹ is independently 0 or 1 It represents an integer, provided ^{that, a 1 + b 1 + c} 1 + d 1 is 1, 2 or 3, if ^{a 1} is 0 ^{d 1} is 0, if ^{a 1} is 1 ^{c 1} is 0 .)
A liquid crystal compound (II) represented by the general formula (III-a)

（式（ＩＩＩ−ａ）中、Ｒ^３及びＲ^４はそれぞれ独立して水素原子又はメチル基を表し、
Ｃ^４及びＣ^５はそれぞれ独立して１，４−フェニレン基、１，４−シクロへキシレン基、ピリジン−２，５−ジイル基、ピリミジン−２，５−ジイル基、ピリダジン−３，６−ジイル基、１，３−ジオキサン−２，５−ジイル基、シクロヘキセン−１，４−ジイル基、デカヒドロナフタレン−２，６−ジイル基、１，２，３，４−テトラヒドロナフタレン−２，６−ジイル基、２，６−ナフチレン基又はインダン−２，５−ジイル基（これらの基のうち１，４−フェニレン基、１，２，３，４−テトラヒドロナフタレン−２，６−ジイル基、２，６−ナフチレン基及びインダン−２，５−ジイル基は、非置換であるか又は置換基としてフッ素原子、塩素原子、メチル基、トリフルオロメチル基若しくはトリフルオロメトキシ基を１個若しくは２個以上有することができる。）を表し、
Ｚ^３及びＺ^５はそれぞれ独立して単結合又は炭素原子数１から１５のアルキレン基（該アルキレン基中に存在する１個又は２個以上のメチレン基は、酸素原子が相互に直接結合しないものとして、それぞれ独立に酸素原子、−ＣＯ−、−ＣＯＯ−又は−ＯＣＯ−で置換されていても良く、該アルキレン基中に存在する１個又は２個以上の水素原子はそれぞれ独立にフッ素原子、メチル基又はエチル基で置換されていても良い。）を表し、
Ｚ^４は、単結合、−ＣＨ_２ＣＨ_２−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＨ_２ＣＨ_２Ｏ−、−ＯＣＨ_２ＣＨ_２−、−ＣＨ_２ＣＨ_２ＣＨ_２Ｏ−、−ＯＣＨ_２ＣＨ_２ＣＨ_２−、−ＣＨ_２ＣＨ_２ＯＣＯ−、−ＣＯＯＣＨ_２ＣＨ_２−、−ＣＨ_２ＣＨ_２ＣＯＯ−、−ＯＣＯＣＨ_２ＣＨ_２−、−ＣＨ＝ＣＨ−、−Ｃ≡Ｃ−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、−ＣＯＯ−又は−ＯＣＯ−を表し、
ｎ^２は、０、１又は２を表す。ただし、ｎ^２が２を表す場合、複数あるＣ^４及びＺ^４は同じであっても異なっていても良い。）、
一般式（ＩＩＩ−ｂ）

(In formula (III-a), R ³ and R ⁴ each independently represent a hydrogen atom or a methyl group,
C ⁴ and C ⁵ are each independently 1,4-phenylene group, 1,4-cyclohexylene group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, pyridazine-3,6- Diyl group, 1,3-dioxane-2,5-diyl group, cyclohexene-1,4-diyl group, decahydronaphthalene-2,6-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6 -Diyl group, 2,6-naphthylene group or indane-2,5-diyl group (among these groups 1,4-phenylene group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, The 2,6-naphthylene group and indan-2,5-diyl group are unsubstituted or have one fluorine atom, chlorine atom, methyl group, trifluoromethyl group or trifluoromethoxy group as a substituent. May have two or more.) Represent,
Z ³ and Z ⁵ are each independently a single bond or an alkylene group having 1 to 15 carbon atoms (one or two or more methylene groups present in the alkylene group are such that oxygen atoms are not directly bonded to each other) Each independently may be substituted with an oxygen atom, -CO-, -COO- or -OCO-, and one or more hydrogen atoms present in the alkylene group are each independently a fluorine atom, Which may be substituted with a methyl group or an ethyl group)
Z ⁴ is a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —CH ₂ CH ₂ O—, —OCH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ O—, _{-OCH 2 CH 2 CH 2 -,} - CH 2 CH 2 OCO -, - COOCH 2 CH 2 -, - CH 2 CH 2 COO -, - OCOCH 2 CH 2 -, - CH = CH -, - C≡C- _{, -CF 2 O -, - OCF} 2 -, - COO- or an -OCO-,
n ² represents 0, 1 or 2. However, when n ² represents 2, a plurality of C ⁴ and Z ⁴ may be the same or different. ),
Formula (III-b)

（式（ＩＩＩ−ｂ）中、Ｒ^５及びＲ^６はそれぞれ独立して水素原子又はメチル基を表し、Ｃ^６は１，４−フェニレン基、１，４−シクロへキシレン基、ピリジン−２，５−ジイル基、ピリミジン−２，５−ジイル基、ピリダジン−３，６−ジイル基、１，３−ジオキサン−２，５−ジイル基、シクロヘキセン−１，４−ジイル基、デカヒドロナフタレン−２，６−ジイル基、１，２，３，４−テトラヒドロナフタレン−２，６−ジイル基、２，６−ナフチレン基又はインダン−２，５−ジイル基（これらの基のうち１，４−フェニレン基、１，２，３，４−テトラヒドロナフタレン−２，６−ジイル基、２，６−ナフチレン基及びインダン−２，５−ジイル基は、非置換であるか又は置換基としてフッ素原子、塩素原子、メチル基、トリフルオロメチル基若しくはトリフルオロメトキシ基を１個若しくは２個以上有することができる。）を表し、
Ｃ^７及びＣ^８はそれぞれ独立してベンゼン−１，２，４−トリイル基、ベンゼン−１，３，４−トリイル基、ベンゼン−１，３，５−トリイル基、シクロヘキサン−１，２，４−トリイル基、シクロヘキサン−１，３，４−トリイル基又はシクロヘキサン−１，３，５−トリイル基を表し、Ｚ^６及びＺ^８はそれぞれ独立して単結合又は炭素原子数１から１５のアルキレン基（該アルキレン基中に存在する１個又は２個以上のメチレン基は、酸素原子が相互に直接結合しないものとして、それぞれ独立に酸素原子、−ＣＯ−、−ＣＯＯ−又は−ＯＣＯ−で置換されていても良く、該アルキレン基中に存在する１個又は２個以上の水素原子はそれぞれ独立にフッ素原子、メチル基又はエチル基で置換されていても良い。）を表し、
Ｚ^７及びZ^９それぞれ独立して単結合、−ＣＨ_２ＣＨ_２−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＨ_２ＣＨ_２Ｏ−、−ＯＣＨ_２ＣＨ_２−、−ＣＨ_２ＣＨ_２ＣＨ_２Ｏ−、−ＯＣＨ_２ＣＨ_２ＣＨ_２−、−ＣＨ_２ＣＨ_２ＯＣＯ−、−ＣＯＯＣＨ_２ＣＨ_２−、−ＣＨ_２ＣＨ_２ＣＯＯ−、−ＯＣＯＣＨ_２ＣＨ_２−、−ＣＨ＝ＣＨ−、−Ｃ≡Ｃ−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、−ＣＯＯ−又は−ＯＣＯ−を表し、
ｎ^３は、０、１又は２を表すが、ｎ^３が２を表す場合、複数あるＣ^６及びＺ^７は同じであっても異なっていても良く、ｎ^５及びｎ^６はそれぞれ独立して１、２及び３を表す。）
及び一般式（ＩＩＩ−ｃ）

(In formula (III-b), R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group, and C ⁶ represents a 1,4-phenylene group, a 1,4-cyclohexylene group, pyridine-2, 5-diyl group, pyrimidine-2,5-diyl group, pyridazine-3,6-diyl group, 1,3-dioxane-2,5-diyl group, cyclohexene-1,4-diyl group, decahydronaphthalene-2 , 6-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, 2,6-naphthylene group or indane-2,5-diyl group (among these groups, 1,4-phenylene Group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, 2,6-naphthylene group and indan-2,5-diyl group are unsubstituted or substituted with fluorine atom, chlorine Atom, methyl group, trif The Oromechiru group or a trifluoromethoxy group may have one or two or more.) Represent,
C ⁷ and C ⁸ are each independently benzene-1,2,4-triyl group, benzene-1,3,4-triyl group, benzene-1,3,5-triyl group, cyclohexane-1,2,4. -Represents a triyl group, a cyclohexane-1,3,4-triyl group or a cyclohexane-1,3,5-triyl group, Z ⁶ and Z ⁸ are each independently a single bond or an alkylene group having 1 to 15 carbon atoms. (One or two or more methylene groups present in the alkylene group are each independently substituted with an oxygen atom, —CO—, —COO— or —OCO—, assuming that the oxygen atoms are not directly bonded to each other. And one or two or more hydrogen atoms present in the alkylene group may each independently be substituted with a fluorine atom, a methyl group or an ethyl group).
Z ⁷ and Z ⁹ are each independently a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —CH ₂ CH ₂ O—, —OCH ₂ CH ₂ —, —CH ₂ CH _{2. CH 2 O -, - OCH 2} CH 2 CH 2 -, - CH 2 CH 2 OCO -, - COOCH 2 CH 2 -, - CH 2 CH 2 COO -, - OCOCH 2 CH 2 -, - CH = CH-, _{-C≡C -, - CF 2 O -} , - OCF 2 -, - COO- or an -OCO-,
n ³ represents 0, 1 or 2, but when n ³ represents 2, a plurality of C ⁶ and Z ⁷ may be the same or different, and n ⁵ and n ⁶ are each independently 1, 2 and 3 are represented. )
And general formula (III-c)

（式（ＩＩＩ−ｃ）中、Ｒ^７は水素原子又はメチル基を表し、
６員環Ｔ^１、Ｔ^２及びＴ^３はそれぞれ独立的に、

(In formula (III-c), R ⁷ represents a hydrogen atom or a methyl group,
6-membered rings T ¹ , T ² and T ³ are each independently

のいずれか（ただしｍは１から４の整数を表す。）を表し、
ｎ^４は０又は１の整数を表し、
Ｙ^１及びＹ^２はそれぞれ独立して単結合、−ＣＨ_２ＣＨ_２−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＯＯ−、−ＯＣＯ−、−Ｃ≡Ｃ−、−ＣＨ＝ＣＨ−、−ＣＦ＝ＣＦ−、−（ＣＨ_２）_４−、−ＣＨ_２ＣＨ_２ＣＨ_２Ｏ−、−ＯＣＨ_２ＣＨ_２ＣＨ_２−、−ＣＨ_２＝ＣＨＣＨ_２ＣＨ_２−又は−ＣＨ_２ＣＨ_２ＣＨ＝ＣＨ−を表し、
Ｙ^３は単結合、−ＣＯＯ−、又は−ＯＣＯ−を表し、
Ｒ^８は炭素原子数１から１８の炭化水素基を表す。）からなる群より選ばれる少なくとも１種の重合性化合物（ＩＩＩ）と、を含有することを特徴とする高分子安定化強誘電性液晶組成物を提供する。また、本願はこの高分子安定化強誘電性液晶組成物を用いた液晶表示素子を提供する。

(Where m represents an integer of 1 to 4),
n ⁴ represents an integer of 0 or 1,
Y ¹ and Y ² are each independently a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —COO—, —OCO—, —C≡C—, —CH═CH—. , —CF═CF—, — (CH ₂ ) ₄ —, —CH ₂ CH ₂ CH ₂ O—, —OCH ₂ CH ₂ CH ₂ —, —CH ₂ ═CHCH ₂ CH ₂ — or —CH ₂ CH ₂ CH = CH-
Y ³ represents a single bond, —COO—, or —OCO—,
R ⁸ represents a hydrocarbon group having 1 to 18 carbon atoms. And a polymer-stabilized ferroelectric liquid crystal composition comprising at least one polymerizable compound (III) selected from the group consisting of: The present application also provides a liquid crystal display device using the polymer-stabilized ferroelectric liquid crystal composition.

  The polymer-stabilized ferroelectric liquid crystal display device comprising the polymer-stabilized ferroelectric liquid crystal composition of the present invention as a constituent member has a low driving voltage, and can provide a stable display by TFT driving. It is possible to display halftones, which is impossible with a single display element, and has excellent thermal and mechanical stability. Furthermore, it is useful as a structural member for plastic liquid crystal cells and the like.

An example of the present invention will be described below. In the polymer-stabilized ferroelectric liquid crystal composition of the present invention, the radically polymerizable compound contained therein is polymerized by active energy rays such as heat or ultraviolet rays, and accordingly, phase separation from the liquid crystal composition or the liquid crystal composition. It is used to obtain a polymer-stabilized liquid crystal display element comprising a transparent polymer material and a liquid crystal composition, causing a state dispersed in the product. This element is a liquid crystal element having an alignment control film and a liquid crystal layer between a substrate having a pair of electrode layers, wherein the liquid crystal layer is at least a liquid crystalline polymer precursor (liquid crystalline monomer) and a non-liquid crystalline polymer precursor ( A photocurable composition of a photocurable composition containing a non-liquid crystalline monomer) and a ferroelectric liquid crystal material, and the mesogenic group of the liquid crystalline monomer in a state where no voltage is applied between a pair of electrode layers. The polymer was stabilized so that the alignment direction, or the long axis direction of the polymer main chain of the non-liquid crystalline monomer, and the alignment direction of the ferroelectric liquid crystal material were aligned with the alignment direction of the alignment control film to be uniaxial alignment. A liquid crystal display device, in which a photocured product of a photocurable composition containing a liquid crystalline monomer and a non-liquid crystalline monomer is dispersed and contained in a liquid crystal layer, and ferroelectricity due to a polymer chain having a liquid crystalline skeleton Alignment stabilization effect of liquid crystal materials Therefore, when no voltage is applied, the major axis of the liquid crystal skeleton of the liquid crystalline monomer, the major axis direction of the non-liquid crystalline monomer and the orientation direction of the ferroelectric liquid crystal material, or the ferroelectric liquid crystal molecules are averaged. Alignment direction of the alignment direction realizes an alignment state in which the alignment direction of the ferroelectric liquid crystal material is changed to the liquid crystal polymer precursor liquid crystal due to the spontaneous polarization of the ferroelectric liquid crystal when a voltage is applied. It is not the orientation direction of the skeleton, but the property that the orientation direction of the ferroelectric liquid crystal material or the angle between the averaged orientation direction and the orientation direction of the liquid crystal skeleton of the liquid crystalline monomer is continuously changed by changing the voltage is given. It is a thing. For example, by arranging the element between two polarizing plates and changing the applied voltage, the amount of transmitted light can be controlled continuously, such as area gradation performed by a single element of ferroelectric liquid crystal. This enables halftone display proportional to the applied voltage without using any special means. The uniaxial orientation described above is a method using a polymer orientation film such as polyimide that has been rubbed so as to obtain a uniaxial orientation, a method using an inorganic orientation film, a method using a photo-alignment film, and a method using an external field such as an electric field or a magnetic field. The polymer is stabilized by exposing the ultraviolet light to a state in which the long axis of the mesogenic group or polymer main chain is aligned by a method using an alignment film and the external field in combination.
In the polymer-stabilized liquid crystal display device thus formed, the driving voltage and light scattering increase in proportion to the content of the monomer added to the composition. When the monomer content is very small, the degree of increase in driving voltage is reduced, but the thermal and mechanical stability is poor. In order to increase the reliability, it is necessary to increase the monomer content. At this time, however, an increase in driving voltage, a decrease in liquid crystal alignment, and the appearance of scattering properties become problems. For example, Japanese Patent Laid-Open No. 6-222320 discloses the relationship of the following equation as an increase in the driving voltage as a description relating to the driving voltage of the polymer dispersed liquid crystal display element. The concept for the driving voltage of the polymer-stabilized liquid crystal element is the same as that of the polymer-dispersed liquid crystal display element, and is as follows.

(Vth represents a threshold voltage, ¹ Kii and ² Kii represent elastic constants, i represents 1, 2 or 3, Δε represents dielectric anisotropy, and <r> represents a transparent polymer substance. (Indicates the average gap distance of the interface, A indicates the anchoring energy of the transparent polymer material with respect to the liquid crystal composition, and d indicates the distance between the substrates having transparent electrodes.)

  According to this, the driving voltage of the polymer-stabilized liquid crystal display element includes the average gap distance at the interface of the transparent polymer substance, the distance between the substrates, the elastic constant / dielectric anisotropy of the liquid crystal composition, and the liquid crystal composition. It is determined by the anchoring energy between transparent polymer materials. Among these, in general liquid crystal display elements, the driving voltage is determined by the cell thickness, the dielectric anisotropy, and the elastic constant, but there are specific factors in the polymer stabilized liquid crystal display elements as in the polymer dispersed liquid crystal. . It is the anchoring energy between the liquid crystal composition and the transparent polymer material. Therefore, also in the polymer-stabilized liquid crystal display element, the area of the interface between the polymer and the liquid crystal is increased and the anchoring energy of the system is increased to increase the driving voltage. In other words, when the content of the liquid crystalline monomer is increased in the composition of the present invention, it means that the driving voltage is increased. In order to reduce the increase in drive voltage and maintain a low drive voltage, the anchoring energy of the polymer constituting the polymer-stabilized liquid crystal composition may be lowered. For example, the effect of the liquid crystalline monomer is to stabilize the uniaxial orientation of the low-molecular liquid crystal as a polymer. On the other hand, the non-liquid crystalline monomer serves to reduce an increase in driving voltage due to the liquid crystalline polymer by using the non-liquid crystalline polymer having a weak anchoring force with respect to the low molecular liquid crystal. By adjusting the composition by using the liquid crystalline monomer and the non-liquid crystalline monomer used in the composition together, the driving voltage, which is a problem, can be lowered while maintaining the reliability of polymer stabilization. In order to reduce the energy of the non-liquid crystalline monomer, a bifunctional monomer having an alkyl side chain may be used. In particular, the alkyl side chain preferably has 5 to 15 carbon atoms, and more preferably 8 to 13 carbon atoms. When the alkyl side chain is short, the anchoring energy is high, and when it is too long, the influence of the side chain is strong and the anchoring energy is high. Further, if a mesogenic group having a benzene ring or the like similar to a low-molecular liquid crystal is used as a side chain, the affinity with the low-molecular liquid crystal is increased and the anchoring energy is increased, which is not preferable. Furthermore, the distance between the alkyl side chains is also important, and is preferably 6 to 18 in terms of the number of carbon atoms. Although it depends on the liquid crystal composition to be used, if the distance between the alkyl side chains is narrow, the low-molecular liquid crystal is not preferred because it is vertically aligned at the polymer interface.

  The anchoring energy is determined by the balance between the intermolecular interaction that the side chain exerts on the low-molecular liquid crystal and the intermolecular interaction that the main chain exerts on the low-molecular liquid crystal. Be minimized. Furthermore, the distance between crosslinks of the polymer affects the thermal mobility of the polymer main chain. If the distance between crosslinks is short and the thermal mobility is low, the molecular interaction with the low-molecular liquid crystal is strong and the anchoring energy is increased. As the distance between crosslinks becomes longer, the thermal mobility of the polymer main chain increases and the fluctuation due to the heat of the main chain increases, and if the fluctuation force becomes larger than the intermolecular interaction force, it acts to cancel the intermolecular interaction Anchoring energy is reduced. However, when the distance between crosslinks is long, the polymerization rate of the monomer is slowed, and the compatibility with the liquid crystal is lowered, which is not preferable. As an index representing the thermal mobility of the polymer main chain, a polymer glass transition temperature is generally used.

  In the present invention, it is preferable to use a monomer having a glass transition temperature of room temperature or lower for the purpose of lowering anchoring, and it is more preferable that the glass transition temperature is 0 to -100 ° C. In addition, in order to lower the glass transition temperature, it is preferable to lower the glass transition temperature in order to improve mechanical stability. If the glass transition temperature is higher than room temperature, the polymer network structure that stabilizes the liquid crystal alignment with the polymer may be deformed or damaged due to deformation from the outside of the device, etc. . When the glass transition temperature is low, even if the network structure is deformed, the original orientation is restored by the elasticity of the network and the fixed orientation is maintained. That is, the liquid crystal composition used in the present invention, the main chain length and the side chain length of the monomer are adjusted, and a monomer having a glass transition temperature of room temperature or lower is used, so that the driving voltage is low and the polymer is highly reliable. A stabilized liquid crystal element is obtained. However, in the polymer-stabilized liquid crystal, it is an important issue to stabilize the initial alignment at the time of manufacturing the liquid crystal display element.

Light scattering is observed when the average gap interval falls within the range of the wavelength range of visible light, and scattering is strongest from about 500 nm to about 1500 nm. In the case of a polymer-stabilized liquid crystal, it is important to form it in the liquid crystal so as to avoid the network size of the network polymer from the above range. To make it 500 nm or less, a method using a phase separation process by spinodal decomposition, a method of making a UV polymerization speed faster (a method by a UV polymerization process or a method by adjusting a polymer precursor composition), a low molecular liquid crystal and Examples include a method of polymerizing in a compatible state with almost no phase separation, and it is preferable to use these techniques effectively to form a fine network polymer that does not cause light scattering. When the monomer is compatible with the low-molecular liquid crystal, it is more preferable that the network polymer can be formed in a dispersed state in the low-molecular liquid crystal and a fine structure at the molecular level can be obtained. However, when polymerization microphase separation occurs minimally when the monomer of the present invention is polymerized in the liquid crystal phase, a network polymer is formed along the liquid crystal molecule director, although the order of orientation is not high. It is observed with an electron microscope or the like. This is because when the monomer comes into contact with the liquid crystal, the major axis of the monomer molecule tends to be aligned in the direction of the liquid crystal molecule director, and the alignment of the liquid crystal is fixed by polymerizing the monomer. However, when the concentration of the monomer is increased, the phase separation structure caused by spinodal decomposition or binodal decomposition caused by polymerization microphase separation is formed ignoring the alignment of the liquid crystal, so that the target liquid crystal alignment cannot be fixed. The above-mentioned method may disturb the orientation of the low-molecular liquid crystal. In this case, the electric field, the orientation regulating force of the orientation film, the external magnetic field, etc. are used so as to obtain the desired stabilizing orientation. The external field can also be adjusted so as to obtain the target polymer-stabilized liquid crystal element. Furthermore, it is a copolymer of liquid crystalline monomers and non-liquid crystalline monomers to form a regular periodic structure by applying the self-organization properties of mesogenic groups and self-organization based on hydrogen bonding groups. Also good. If necessary to obtain desired characteristics, a structure in which fine polymer particles are dispersed in a low-molecular liquid crystal may be used.
Thus, by using a polymer-stabilized ferroelectric liquid crystal composition composed of a liquid crystalline monomer and a non-liquid crystalline monomer, the driving voltage is low, halftone display is possible, and the reliability of polymer stabilization is high. In addition, it is possible to obtain a high-contrast liquid crystal display element having a high tilt angle, no light scattering, and a large tilt angle. In order to fix the aligned state of the liquid crystal with the alignment film or the like without alignment defects, it is preferable to remove at least the nematic phase and make the phase transition to the smectic phase, and the substrate surface of the liquid crystal cell to be used is flat It is more preferable. Further, it is necessary to polymerize the monomer in a network or dispersed state in a liquid crystal phase such as a nematic phase or a smectic phase. Furthermore, in order to avoid the formation of the phase separation structure, the content of the polymer precursor is reduced so that a network polymer can be formed between the liquid crystal molecules while the content of the monomer is reduced and the liquid crystal is aligned. It is preferable to adjust the composition of the precursor. Further, in the case of photopolymerization, the UV exposure time, UV exposure intensity, and temperature are adjusted to form a network polymer so that there are no liquid crystal alignment defects. It is preferable to do. In addition, in order to obtain a desired liquid crystal alignment when polymerizing the monomers in the composition, an alignment film subjected to vertical alignment, parallel alignment or antiparallel alignment rubbing alignment treatment or photo-alignment treatment, or an inorganic shape It is possible to use a liquid crystal cell having an alignment film utilizing the effect, a liquid crystal cell in which the upper and lower substrates are a vertical alignment film, or a combination of a vertical alignment film and a parallel alignment. Furthermore, a twisted alignment obtained by applying an external field such as light, heat, voltage, magnetic field, bent alignment, splay alignment, parallel alignment, etc., or a liquid crystal alignment state that is difficult to obtain with only an alignment film, By polymerizing monomers, the alignment state thereof can be fixed to obtain a target polymer-stabilized liquid crystal display element. For example, in the smectic phase, the alignment state in which the directors are aligned in a certain direction due to the external field is stabilized, or the excessive alignment state is fixed by polymerizing by switching and the desired polymer stabilized liquid crystal display An element can also be obtained.

The polymer-stabilized ferroelectric liquid crystal composition of the present invention can be suitably used for a liquid crystal display element based on a V-shaped response, a liquid crystal display element based on a Half-V response, a liquid crystal display element based on a polarization blocking effect, and the like. .

The monomer used in the present invention has arrived as a result of searching for a compound having a greater improvement effect as a monomer as described above.
The polymer-stabilized ferroelectric liquid crystal composition of the present invention comprises a non-liquid crystalline monomer (I) represented by the general formula (Ia)
And at least one liquid crystalline monomer selected from the group consisting of the liquid crystal compound (II) represented by the general formula (II) and the general formulas (III-a), (III-b) and (III-c) It contains at least one kind of (III).

  The non-liquid crystalline monomer (I) may contain a plurality of non-liquid crystalline monomers (Ia) having different main chain lengths or alkyl side chain lengths. Furthermore, you may use a polymerizable liquid crystal compound together as needed. When a polymerizable liquid crystal compound is used, the orientation of the low-molecular liquid crystal can be improved. However, the affinity for the low-molecular liquid crystal is high and the driving voltage is likely to increase, so 5% or less is preferable. Driven by the action of low anchoring energy and low glass transition temperature by the non-liquid crystalline monomer (I) represented by the general formula (Ia), with the orientation improved by the combined use of the liquid crystalline monomer (III). A polymer-stabilized liquid crystal display element having a low voltage and high mechanical strength can be obtained.

The liquid crystalline compound (II) may include a plurality of compounds represented by the general formula (II) having different alkyl chain lengths, alkyl chain structures, bonding portion structures, ring structures, and ring numbers. good. In order to lower the melting point and exhibit a ferroelectric liquid crystal phase in a wide temperature range, it is preferable to mix two or more different compounds.

Furthermore, as a component of the ferroelectric liquid crystal composition, a liquid crystal compound other than the liquid crystal compound represented by the general formula (II) can be used in combination as necessary. The compound that can be used in combination is not particularly limited, but in order to stabilize the ferroelectric liquid crystal phase, it is preferable to use a liquid crystalline compound exhibiting a smectic C phase or a chiral smectic C phase. (In this specification, the name of the liquid crystal phase includes the corresponding chiral liquid crystal phase unless otherwise specified.) In addition, the phase series of the ferroelectric liquid crystal phase or the temperature range of each liquid crystal phase is defined. In order to adjust, it is preferable to select a liquid crystal compound as appropriate. Specifically, in order to develop a nematic phase or expand the temperature range of the nematic phase, it is preferable to use a compound exhibiting a nematic phase in combination, or to develop a smectic A phase or a smectic A phase. When it is desired to expand the temperature range, it is preferable to use a compound exhibiting a smectic A phase, or a compound that does not exhibit a smectic A phase when a smectic A phase is unnecessary, such as a Half-V material. It is preferable to use together.

In order to obtain a display element with good contrast, it is necessary to adjust the tilt angle according to the display method. In order to increase the tilt angle, it is preferable to select a compound so as to increase the upper limit temperature of the smectic C phase or to narrow the temperature range of the smectic A phase. To reduce the tilt angle, the smectic C phase is preferred. It is preferable to use a compound that lowers the upper limit temperature of the phase or widens the temperature range of the smectic A phase.

In order to stabilize the smectic layer structure, it is preferable to use a phenylbenzoate derivative in combination with the compound of the general formula (II). Since these phenylbenzoate derivatives or biphenylbenzoate derivatives increase the viscosity of the composition, the layer structure can be stabilized, and it is preferable for suppressing orientation disorder. Moreover, the effect that a melting point falls by mixing with a phenylbenzoate derivative is acquired, and it is preferable. However, the use of the phenylbenzoate derivative increases the viscosity and slows the response speed. Therefore, the phenyl benzoate derivative is preferably used within a range where a desired response speed can be obtained.

In order to obtain a ferroelectric liquid crystal phase having a low melting point and stable at low temperatures, a compound of the general formula (II) and a compound having a ring structure at the end of the compound, or a pyridine ring, pyrazine ring or pyridazine as the ring structure It is preferable to use a compound having a ring or a compound having both structures in combination. A compound having a pyridine ring, a pyrazine ring or a pyridazine ring as a ring structure is preferable for lowering the melting point, but due to the polar nature of the structure, the amount used does not adversely affect the switching behavior when used as a device. Is preferred. Among these compounds, a compound having a pyridine ring is particularly preferable as an effect of decreasing the melting point. It is preferable to use a compound having fluorine introduced in the ring structure of these compounds in order to lower the melting point. In addition, it is preferable to use a compound having a branched structure introduced in the alkyl chain of these compounds in order to lower the melting point. However, since the upper limit temperature of the liquid crystal phase also changes at the same time, it is preferable to adjust the amount of use so that the desired smectic C phase temperature range is obtained.

As the compound having a ring structure at the molecular end, a compound represented by the general formula (IV-a) is particularly preferable. Even if only one compound (IV-a) represented by the general formula (IV-a) is used in combination with the liquid crystal compound (II), an effect is seen. Among the compounds (IV-a), the alkyl chain length In addition, a plurality of alkyl chains having different structures, different bond structures, ring structures, and different numbers of rings may be contained.

As the chiral component for expressing the ferroelectricity of the ferroelectric liquid crystal composition, known and commonly used chiral compounds can be used. As the chiral compound, a compound having an asymmetric atom or a compound having an axial irregularity is preferably used, and a compound having an irregular carbon or a compound having an irregularity around a carbon-carbon bond is preferably used. The irregular carbon may be introduced into a part of the chain structure or may be introduced into a part of the cyclic structure. As the irregular carbon, it is more preferable that a fluorine atom, a methyl group, or a CF ₃ group is introduced on the carbon. In particular, a chiral compound (Va) represented by the general formula (Va) is used. It is still preferred. As for the chiral compound, one compound having the structure represented by (Va) may be used, or plural compounds having different chiral structure, alkyl chain length, alkyl chain structure, bond structure, ring structure, and ring number may be used. It may be used. In order to suppress the helical structure in the liquid crystal phase generated based on the chiral effect, it is preferable to use a combination of a plurality of chiral compounds having different directions of twist to be generated. At this time, if the combination of chiral compounds is selected so that the directions of spontaneous polarization are aligned, or if a combination of a compound that generates sufficiently large spontaneous polarization and a compound that induces a twisted structure but has a small spontaneous polarization value is selected, The value is preferred because it is not canceled. It is also preferable to introduce a plurality of chiral structures having different twist directions to be introduced into the same compound in order to suppress the generation of a helical structure that occurs in the liquid crystal phase based on the chiral effect. At this time, if a combination of chiral structures is selected so that the directions of spontaneous polarization are aligned, or if a combination of structures that induce sufficiently large spontaneous polarization and a torsional structure is induced but has a small spontaneous polarization value, The value is preferred because it is not canceled.

  The two substrates of the liquid crystal cell can be made of a transparent material having flexibility such as glass or plastic, and one of them can be an opaque material such as silicon. A transparent substrate having a transparent electrode layer can be obtained, for example, by sputtering indium tin oxide (ITO) on a transparent substrate such as a glass plate.

  The color filter can be prepared by, for example, a pigment dispersion method, a printing method, an electrodeposition method, or a dyeing method. A method for producing a color filter by a pigment dispersion method will be described as an example. A curable coloring composition for a color filter is applied on the transparent substrate, subjected to patterning treatment, and cured by heating or light irradiation. By performing this process for each of the three colors red, green, and blue, a pixel portion for a color filter can be created. In addition, a pixel electrode provided with an active element such as a TFT, a thin film diode, or a metal insulator metal specific resistance element may be provided on the substrate.

  The said board | substrate is made to oppose so that a transparent electrode layer may become an inner side. In that case, you may adjust the space | interval of a board | substrate through a spacer. In this case, it is preferable to adjust the thickness of the obtained cell to be 1 to 100 μm. The cell thickness is more preferably 1 to 10 μm, still more preferably 1 to 3 μm. When a polarizing plate is used, it is preferable to adjust the product of the refractive index anisotropy Δn of the liquid crystal and the cell thickness d so that the contrast is maximized. In addition, when there are two polarizing plates, the polarizing axis of each polarizing plate can be adjusted so that the viewing angle and contrast are good. Furthermore, a retardation film for widening the viewing angle can also be used. Examples of the spacer include glass particles, plastic particles, alumina particles, and a photoresist material. Thereafter, a sealant such as an epoxy thermosetting composition is screen-printed on the substrates with a liquid crystal inlet provided, the substrates are bonded together, and heated to thermally cure the sealant.

  As a method for sandwiching the polymer-stabilized ferroelectric liquid crystal composition between two substrates, a normal vacuum injection method, an ODF method, or the like can be used. At this time, the polymer-stabilized ferroelectric liquid crystal composition only needs to be compatible with various liquid crystal compounds and the monomer of the present invention, and is preferably in a uniform isotropic state or a (chiral) nematic phase. . In the smectic phase, handling during device fabrication becomes difficult.

  As a method for polymerizing the radically polymerizable compound, ultraviolet irradiation is suitable. As a lamp for generating ultraviolet rays, a metal halide lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, or the like can be used. In addition, the wavelength of the ultraviolet rays to be irradiated is an absorption wavelength region of the photopolymerization initiator contained in the polymer-stabilized ferroelectric liquid crystal composition, and a wavelength that is not the absorption wavelength region of the contained liquid crystal composition. It is preferable to irradiate ultraviolet rays in the region. Specifically, it is preferable to cut and use ultraviolet rays of 330 nm or less using a metal halide lamp, high-pressure mercury lamp, or ultra-high pressure mercury lamp, and cut ultraviolet rays of 350 nm or less. And more preferably used.

Intensity of ultraviolet light irradiation, can be appropriately adjusted to obtain a light control layer of interest, preferably 10000 mJ / cm ² from but 10 depends on the reactivity of the monomers used, is 5000 mJ / cm ² from 50 More preferred. The time for irradiation with ultraviolet rays is appropriately selected depending on the intensity of ultraviolet rays to be irradiated, but is preferably 5 to 600 seconds.

  The temperature at the time of ultraviolet irradiation is an important factor for stabilizing the desired initial alignment of the liquid crystal by determining the characteristics of the light control layer. In the case of fixing the isotropic phase state, a temperature slightly higher than the isotropic-nematic transition point of the composition for a polymer-stabilized liquid crystal display element is preferable, and specifically, the transition point +0.1 to 10 ° C. is preferable. The transition point + 0.1 ° C. to 3 ° C. is more preferable. In addition, the device can be manufactured at a temperature showing a nematic phase, a smectic phase, or a cholesteric phase.

  The alignment state of the liquid crystal to stabilize the polymer includes bend alignment, twist alignment, splay alignment, etc. found in smectic and nematic phases, multi-domains combining them, and monodomains with uniaxial alignment in multiple directions. Necessary orientation states such as arranged multi-domains can be mentioned. These alignment states can be achieved by changing the temperature, changing the voltage by applying an external electric field, or processing the alignment treatment direction of the polyimide alignment film or photo-alignment film existing at the substrate interface in one direction or multiple directions. It is preferable to align the liquid crystal, create the desired alignment state by various methods, and stabilize the polymer by ultraviolet exposure.

  The polymer-stabilized liquid crystal display element of the present invention stabilizes the alignment state of low-molecular liquid crystals by polymerizing the polymer-stabilized ferroelectric liquid crystal composition of the present invention and forming a polymer chain in the liquid crystal phase. It is a thing. Such a polymer-stabilized liquid crystal display device maintains a desired alignment state by applying an external electric field to the polymer-stabilized ferroelectric liquid crystal composition or controlling the alignment of the polymerizable liquid crystal by an alignment film. However, it can be obtained by ultraviolet exposure and polymerization.

  A specific example of the compound used in the polymer-stabilized ferroelectric liquid crystal composition of the present invention is shown below.

<Polymerizable compound (I)>
The polymerizable compound (I) used in the polymer-stabilized ferroelectric liquid crystal composition of the present invention is represented by the general formula (Ia)
A polymerizable compound represented by the formula is used.

In the present invention, unless otherwise specified, the “alkylene group” is a divalent group “— (CH ₂ ) _n, wherein one hydrogen atom is removed from carbon atoms at both ends of an aliphatic linear hydrocarbon. -"(Where n is an integer of 1 or more), and the substitution from a hydrogen atom to a halogen atom or an alkyl group, or from a methylene group to an oxygen atom, -CO-, -COO- or -OCO- If there is a substitution, this shall be specifically refused. Further, the “alkylene chain length” refers to n in the general formula “— (CH ₂ ) _n —” of the “alkylene group”.
As a preferable structure of the polymerizable compound (I) represented by the general formula (Ia), the following general formula (Ic)

(In the formula (Ic), A ¹¹ and A ¹⁹ each independently represent a hydrogen atom or a methyl group,
A ¹² and A ¹⁸ are each independently a single bond or an alkylene group having 1 to 15 carbon atoms (one or two or more methylene groups present in the alkylene group are such that oxygen atoms are not directly bonded to each other) Each independently may be substituted with an oxygen atom, -CO-, -COO- or -OCO-, and one or more hydrogen atoms present in the alkylene group are each independently a fluorine atom, Which may be substituted with a methyl group or an ethyl group)
A ¹³ and A ¹⁶ are each independently a linear alkyl group having 2 to 20 carbon atoms (one or two or more methylene groups present in the linear alkyl group are such that oxygen atoms are not directly bonded to each other) And may be independently substituted with an oxygen atom, -CO-, -COO-, or -OCO-).
A ¹⁴ and A ¹⁷ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (one or two or more methylene groups present in the alkyl group are such that oxygen atoms are not directly bonded to each other) Each independently may be substituted with an oxygen atom, -CO-, -COO- or -OCO-, and one or more hydrogen atoms present in the alkyl group are each independently a halogen atom or carbon. Which may be substituted with an alkyl group of 1 to 9 atoms).
A ¹⁵ represents an alkylene group having 9 to 16 carbon atoms (in the alkylene group, at least 1 to 5 methylene groups, one of the hydrogen atoms in the methylene group is independently 1 carbon atom) To one or more methylene groups present in the alkylene group are each independently an oxygen atom, assuming that the oxygen atoms are not directly bonded to each other. , -CO-, -COO- or -OCO- may be substituted). ), A compound represented by the general formula (Id)

(In Formula (Id), A ²¹ and A ²² each independently represents a hydrogen atom or a methyl group, and a represents an integer of 6 to 22), a general formula (I- e)

(In Formula (Ie), A ³¹ and A ³² each independently represent a hydrogen atom or a methyl group, b and c each independently represent an integer of 1 to 10, and d is an integer of 1 to 10) Represents
e represents an integer of 0 to 6; And a compound represented by formula (If)

(In formula (If), A ⁴¹ and A ⁴² each independently represents a hydrogen atom or a methyl group, and m, n, p and q each independently represents an integer of 1 to 10). 1 type or more chosen from the group which consists of a compound to be mentioned. Among these, it is preferable that the compound represented by Formula (Ic) is included.

As a preferable structure of the polymerizable compound represented by the general formula (Ic), it is preferable that both A ¹¹ and A ¹⁹ are hydrogen atoms. The effects of the present invention are also exhibited in compounds in which these substituents A ¹¹ and A ¹⁹ are methyl groups, but compounds having hydrogen atoms are advantageous in that the polymerization rate is faster.

A ¹² and A ¹⁸ are preferably each independently a single bond or an alkylene group having 1 to 3 carbon atoms. The distance between the two polymerizable functional groups can be adjusted by independently changing the length of the carbon number of A ¹² and A ¹⁸ and A ¹⁵ , respectively. The feature of the compound represented by the general formula (Ic) is that the distance between the polymerizable functional groups (distance between the crosslinking points) is long, but if this distance is too long, the polymerization rate becomes extremely slow. Therefore, there is an upper limit to the distance between polymerizable functional groups. On the other hand, the distance between the two side chains of A ¹³ and A ¹⁶ also affects the mobility of the main chain. That is, if the distance between A ¹³ and A ¹⁶ is short, the side chains A ¹³ and A ¹⁶ will interfere with each other, resulting in a decrease in mobility. Therefore, in the compound represented by the general formula (Ic), the distance between polymerizable functional groups is determined by the sum of A ¹² , A ¹⁸ , and A ¹⁵ , but among these, A ¹² and A ¹⁸ are made longer than A ¹² is made longer. It is preferable to lengthen ¹⁵ .

On the other hand, in the side chains A ¹³ , A ¹⁴ , A ¹⁶ and A ¹⁷ , it is preferable that the length of these side chains has the following aspect.

In the general formula (Ic), A ¹³ and A ¹⁴ are bonded to the same carbon atom of the main chain. When these lengths are different, the longer side chain is referred to as A ¹³ ( If the length and the length of ^{a 14} of a ¹³ are equal, one to one and ^{a 13).} Similarly, when the length of the length and A ¹⁷ of A ¹⁶ are different, if the length and the length of A ¹⁷ in the longer side chain of is referred to as A ¹⁶ (A ¹⁶ are equal, either the one and a ^16).

In the present application, such A ¹³ and A ¹⁶ are each independently a linear alkyl group having 2 to 20 carbon atoms (one or two or more methylene groups present in the linear alkyl group are oxygen As the atoms are not directly bonded to each other, each may be independently substituted with an oxygen atom, -CO-, -COO-, or -OCO-).
Preferably, each independently a linear alkyl group having 2 to 18 carbon atoms (one or two or more methylene groups present in the linear alkyl group are such that oxygen atoms are not directly bonded to each other, Each independently may be substituted with an oxygen atom, -CO-, -COO- or -OCO-).
More preferably, each independently a linear alkyl group having 3 to 15 carbon atoms (one or two or more methylene groups present in the linear alkyl group are such that oxygen atoms are not directly bonded to each other). And each may be independently substituted with an oxygen atom, —CO—, —COO— or —OCO—.

  Since the side chain has higher mobility than the main chain, its presence contributes to improvement of the mobility of the polymer chain at low temperature, but as mentioned above, spatial interference occurs between the two side chains. On the contrary, motility decreases. In order to prevent such spatial interference between side chains, it is effective to increase the distance between the side chains and to shorten the side chain length within a necessary range.

Furthermore, for A ¹⁴ and A ¹⁷ , in the present application, each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (one or two or more methylene groups present in the alkyl group have an oxygen atom Each may be independently substituted with an oxygen atom, —CO—, —COO—, or —OCO— so that one or two or more hydrogen atoms present in the alkyl group are each independently May be substituted with a halogen atom or an alkyl group having 1 to 9 carbon atoms).
Preferably, each independently represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms (one or two or more methylene groups present in the alkyl group are independently represented as those in which oxygen atoms are not directly bonded to each other). An oxygen atom, -CO-, -COO- or -OCO- may be substituted).
More preferably, they are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms (one or two or more methylene groups present in the alkyl group are independent as those in which oxygen atoms are not directly bonded to each other). May be substituted with an oxygen atom, -CO-, -COO- or -OCO-).
More preferably, they are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms (one or two or more methylene groups present in the alkyl group are independent as those in which oxygen atoms are not directly bonded to each other). May be substituted with an oxygen atom, -CO-, -COO-, or -OCO-).

This A ¹⁴ and A ¹⁷ also, the possible length too long is not preferable for inducing the spatial interference between side chains. On the other hand, when A ¹⁴ and A ¹⁷ are alkyl chains having a short length, they can be side chains having high mobility and have a function of inhibiting the proximity of adjacent main chains. It is thought that it acts to prevent interference between polymer main chains, and it is thought that the mobility of the main chains is enhanced. This is effective in improving the display characteristics in the low temperature region of the device.

A ¹⁵ located between the two side chains is preferably longer in terms of changing the distance between the side chains and increasing the distance between the crosslinking points to lower the glass transition temperature. However to come formula compatibility with the liquid crystal composition has too high a molecular weight (I-c) compounds represented by is reduced when A ¹⁵ is too long, and the polymerization rate slows down too phase separation The length is naturally set to an upper limit because of adverse effects on the length.

Therefore, in the present invention, A ¹⁵ represents an alkylene group having 9 to 16 carbon atoms (in the methylene group of at least 1 to 5 carbon atoms present in the alkylene group, one of the hydrogen atoms in the methylene group is Independently substituted with a linear or branched alkyl group having 1 to 10 carbon atoms, wherein one or more methylene groups present in the alkylene group are such that oxygen atoms are not directly bonded to each other. And each may be independently substituted with an oxygen atom, —CO—, —COO— or —OCO—.

That is, in the present invention, the alkylene chain length of A ¹⁵ is preferably 9 to 16 carbon atoms. A ¹⁵ has a structure in which a hydrogen atom in an alkylene group is substituted with an alkyl group having 1 to 10 carbon atoms as a structural feature. The number of substitution of the alkyl group is 1 or more and 5 or less, preferably 1 to 3, and more preferably 2 or 3 substitutions. The number of carbon atoms of the alkyl group to be substituted is preferably 1 to 5, and more preferably 1 to 3.

  The compound represented by the general formula (Ia) is described in Tetrahedron Letters, Vol. 30, pp 4985, Tetrahedron Letters, Vol. 23, No. 6, pp 681-684, and Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 34, pp217-225 and the like.

For example, in the general formula (I-c), Compound A ¹⁴ and A ¹⁷ are hydrogen, a compound having a plurality of epoxy groups, polymerizable acrylic acid or methacrylic acid having an active hydrogen reactive with epoxy groups It can be obtained by reacting with a compound to synthesize a polymerizable compound having a hydroxyl group and then reacting with a saturated fatty acid.
Furthermore, by reacting a compound having a plurality of epoxy groups with a saturated fatty acid, synthesizing a compound having a hydroxyl group, and then reacting with a polymerizable compound such as an acrylate chloride having a group capable of reacting with a hydroxyl group. Can be obtained.

When the radically polymerizable compound is, for example, A ¹⁴ and A ^{17 in} the general formula (Ic) are alkyl groups and A ¹² and A ¹⁸ are methylene groups having 1 carbon atom, an oxetane group is selected. A method of reacting a compound having a plurality of compounds with a fatty acid chloride or a fatty acid capable of reacting with an oxetane group, and further reacting with a polymerizable compound having active hydrogen such as acrylic acid, a compound having one oxetane group, It can be obtained by a method of reacting a polyvalent fatty acid chloride or a fatty acid capable of reacting with an oxetane group, and further reacting with a polymerizable compound having active hydrogen such as acrylic acid.

In the case where A ¹² and A ¹⁸ in the general formula (Ic) are an alkylene group having 3 carbon atoms (propylene group; —CH ₂ CH ₂ CH ₂ —), a plurality of furan groups are used instead of the oxetane group. It can obtain by using the compound which has. Further, when A ¹² and A ¹⁸ in the general formula (Ic) are an alkylene group having 4 carbon atoms (butylene group; —CH ₂ CH ₂ CH ₂ CH ₂ —), a pyran group is used instead of the oxetane group. It can obtain by using the compound which has two or more.
Of the compounds of the general formula (Ic) thus obtained, those having the following structures are particularly preferred.

（式（Ｉ−ｃ−１）中、Ａ^１１及びＡ^１９はそれぞれ独立して水素原子又はメチル基を表し、
Ａ^１２及びＡ^１８はそれぞれメチレン基を表し、
Ａ^１３及びＡ^１６はそれぞれ独立して炭素原子数２から２０の直鎖アルキル基（該直鎖アルキル基中に存在する１個又は２個以上のメチレン基は、酸素原子が相互に直接結合しないものとして、それぞれ独立に酸素原子、−ＣＯ−、−ＣＯＯ−又は−ＯＣＯ−で置換されていても良い。）を表し、
Ａ^１４及びＡ^１７はそれぞれ独立して炭素原子数１から１０のアルキル基を表し、
Ａ^１５は炭素原子数９から１６のアルキレン基（該アルキレン基中に存在する少なくとも１個以上５個以下のメチレン基において、該メチレン基中の水素原子の一つはそれぞれ独立に炭素原子数１から１０の直鎖又は分岐のアルキル基で置換されている。該アルキレン基中に存在する１個又は２個以上のメチレン基は、酸素原子が相互に直接結合しないものとして、それぞれ独立に酸素原子、−ＣＯ−、−ＣＯＯ−又は−ＯＣＯ−で置換されていても良い。）を表す。）（１−ｃ−１）で表される化合物のうち、Ａ^１５に含まれる−ＣＯＯ−又は−ＯＣＯ−基の数が２以下で、かつ、Ａ^１３及びＡ^１６に含まれる−ＣＯＯ−又は−ＯＣＯ−基の数がそれぞれ１以下であるものが特に好ましく、具体的には、下記（I-1）から（I-9）の化合物が挙げられる。

(In the formula (Ic-1), A ¹¹ and A ¹⁹ each independently represent a hydrogen atom or a methyl group,
A ¹² and A ¹⁸ each represent a methylene group;
A ¹³ and A ¹⁶ are each independently a linear alkyl group having 2 to 20 carbon atoms (one or two or more methylene groups present in the linear alkyl group are such that oxygen atoms are not directly bonded to each other) And may be independently substituted with an oxygen atom, -CO-, -COO-, or -OCO-).
A ¹⁴ and A ¹⁷ each independently represents an alkyl group having 1 to 10 carbon atoms,
A ¹⁵ represents an alkylene group having 9 to 16 carbon atoms (in the alkylene group, at least 1 to 5 methylene groups, one of the hydrogen atoms in the methylene group is independently 1 carbon atom) To one or more methylene groups present in the alkylene group are each independently an oxygen atom, assuming that the oxygen atoms are not directly bonded to each other. , -CO-, -COO- or -OCO- may be substituted). ) Of the compounds represented by (1-c-1), the number of —COO— or —OCO— groups contained in A ¹⁵ is 2 or less, and —COO— contained in A ¹³ and A ¹⁶ or Those having —OCO— groups of 1 or less are particularly preferred, and specific examples thereof include the following compounds (I-1) to (I-9).

<Ferroelectric liquid crystal component>
In the polymer-stabilized ferroelectric liquid crystal composition of the present invention, the liquid crystal compound (II) has the general formula (II)
Among the compounds represented by the general formula (II), in order to obtain a tilted smectic phase necessary for the development of ferroelectricity, to increase the tilt angle of the molecule, or to increase the melting point In order to lower it, it is preferable that at least one fluorine atom, CF ₃ group, or OCF ₃ group is introduced as a substituent in the ring portion of the molecule. It is preferable to introduce fluorine having a small shape as a substituent in terms of maintaining a stable liquid crystal phase and maintaining high-speed response. The number of substituents is preferably 1 to 4, and more preferably 1 to 3.
Since the viscosity is low and the response speed is high, the coupler connecting the rings includes a single bond, —CH ₂ O—, —OCH ₂ —, —CF ₂ O—, —OCF ₂ —, —CH ₂ CH ₂ —, —CH. ═CH— or —C≡C— is preferable, and a single bond or —CH ₂ O— is particularly preferable. Single bonds are preferred when necessary to obtain good switching to suppress local polarization of the molecule. On the other hand, as the material for maintaining the stability of the layer structure, it is preferable that the viscosity is high. In that case, -CO-O-, -O-CO-, -CO-S-, -S-CO- It is preferably used, and in particular, —CO—O— and —O—CO— are preferably used.
On the other hand, in terms of increasing the effect of lowering the melting point, it is preferable to use an alkylcarbonyloxy group, an alkyloxycarbonyl group, or an alkyloxycarbonyloxy group in the side chain.
As a compound suitable for TFT driving, showing a stable ferroelectric liquid crystal phase and having a low viscosity and suitable for high-speed response, the following general formula (II-b)

（式中、Ｒ^２１１及びＲ^２１２は各々独立に炭素原子数１〜１８の直鎖状又は分岐状のアルキル基を示し、但し、Ｒ^２１１とＲ^２１２が同時にフッ素原子となることはなく、さらに、１つ又は２つの隣接していない−ＣＨ_２−基が−Ｏ−、−ＣＨ＝ＣＨ−、あるいは−Ｃ≡Ｃ−で置き換えられてもよく、Ｘ^２１１〜Ｘ^２１７は各々独立に水素原子、フッ素原子を示し、Ｌ^２１１、Ｌ^２１２、Ｌ^２１３、Ｌ^２１４は各々独立に単結合、、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−であり、ａ^１、ｂ^１、ｃ^１、ｄ^１は各々独立に０又は１の整数を示し、但し、ａ^１＋ｂ^１＋ｃ^１＋ｄ^１は１、２又は３であり、ａ^１が０の場合はｄ^１は０であり、ａ^１が１の場合はｃ^１は０である。）の化合物が好ましい。

その中でも、Ｒ^２１１及びＲ^２１２は各々独立に炭素原子数１〜１８の直鎖状又は分岐状のアルキル基を示し、但し、Ｒ^２１１とＲ^２１２が同時にフッ素原子となることはなく、さらに、１つ又は２つの隣接していない−ＣＨ_２−基が−Ｏ−で置き換えられてもよく、Ｘ^２１１〜Ｘ^２１７は各々独立に水素原子、フッ素原子を示し、但し、Ｘ^２１１〜Ｘ^２１７の少なくともひとつはフッ素原子であり、Ｌ^２１１、Ｌ^２１２、Ｌ^２１３、Ｌ^２１４は各々独立に単結合、、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、ａ^１、ｂ^１、ｃ^１、ｄ^１は各々独立に０又は１の整数を示し、但し、ａ^１＋ｂ^１＋ｃ^１＋ｄ^１は１、２又は３であり、ａ^１が０の場合はｄ^１は０であり、ａ^１が１の場合はｃ^１は０である化合物がさらに好ましい。
一般式（ＩＩ−ｂ）で表される化合物のうち、特に好ましく用いられる化合物を次に示す。

(Wherein R ²¹¹ and R ²¹² each independently represents a linear or branched alkyl group having 1 to 18 carbon atoms, provided that R ²¹¹ and R ²¹² do not simultaneously become a fluorine atom, One or two non-adjacent —CH ₂ — groups may be replaced by —O—, —CH═CH—, or —C≡C—, wherein X ^{211 to} X ²¹⁷ are each independently a hydrogen atom. Represents a fluorine atom, L ²¹¹ , L ²¹² , L ²¹³ , and L ²¹⁴ each independently represent a single bond, —CH ₂ O—, —OCH ₂ —, —CF ₂ O—, —OCF ₂ —, ¹ , b ¹ , c ¹ and d ¹ each independently represents an integer of 0 or 1, provided that a ¹ + b ¹ + c ¹ + d ¹ is 1, 2 or 3, and d ¹ when a ¹ is 0 preferred is 0, compounds of if ^{a 1} is 1 ^{c 1} is zero.) is There.

Among them, R ²¹¹ and R ²¹² each independently represent a linear or branched alkyl group having 1 to 18 carbon atoms, provided that R ²¹¹ and R ²¹² do not simultaneously become a fluorine atom, One or two non-adjacent —CH ₂ — groups may be replaced by —O—, and X ^{211 to} X ²¹⁷ each independently represent a hydrogen atom or a fluorine atom, provided that X ^{211 to} X ²¹⁷ are At least one is a fluorine atom, L ²¹¹ , L ²¹² , L ²¹³ , and L ²¹⁴ are each independently a single bond, —CH ₂ O—, —OCH ₂ —, a ¹ , b ¹ , c ¹ , d ¹ are Each independently represents an integer of 0 or 1, provided that a ¹ + b ¹ + c ¹ + d ¹ is 1, 2 or 3; if a ¹ is 0, d ¹ is 0; and a ¹ is 1 further preferred compounds are c ¹ is 0
Of the compounds represented by the general formula (II-b), particularly preferred compounds are shown below.

（式中、Ｙ^２、Ｚ^２は各々独立に直鎖あるいは分岐の炭素原子数１〜１８のアルキル基、ただし、アルキル基中のひとつの−ＣＨ_２−基が−Ｏ−に置き換えられていてもよい、を示し、Ｕ^２、Ｗ^２は炭素原子数１〜１８のアルキル基を示す。）

(In the formula, Y ² and Z ² are each independently a linear or branched alkyl group having 1 to 18 carbon atoms, provided that one —CH ₂ — group in the alkyl group is replaced by —O—. And U ² and W ² each represent an alkyl group having 1 to 18 carbon atoms.)

More preferably, the number of carbon atoms of Y ² , Z ² , U ² , and W ² is 6 to 12, in order to maintain the stability of the smectic C phase and to keep the upper limit temperature high, or to reduce the viscosity and thus the response speed. In order to increase the speed, the alkyl moiety is preferably linear, while in order to lower the melting point, the alkyl moiety preferably has a branched structure. As the branched structure, an ethyl group or a methyl group branch is preferable, and a methyl branch is particularly preferable because liquid crystallinity is not excessively lowered.
In order to obtain a display element with high transmittance, the birefringence (Δn) must be adjusted depending on the cell thickness. A thicker cell is preferable in terms of manufacturing a display element and obtaining a high-speed response because molecular movement is easy in the cell. In that case, it is necessary to use a liquid crystal having a small Δn. Specific examples of the liquid crystal having a small Δn include those having a cyclohexyl structure as the ring structure of the general formula (II). It is preferable that one or two cyclohexyl structures exist in one molecule. Alternatively, it is preferable to mix cyclohexyl or a compound having a 1,3,4-thiadiazole-2,5-diyl structure with the compound represented by the general formula (II) in order to reduce Δn. In this case, the compound to be added is preferably a compound having one or two cyclohexyl structures in one molecule, and one 1,3,4-thiadiazole-2,5-diyl is present in one molecule. Are preferred. Since a compound having a 1,3,4-thiadiazole-2,5-diyl structure has high polarity, it is desirable to use an amount that does not adversely affect TFT driving.

In terms of stability of the liquid crystal phase, among these compounds, the total number of fluorine introduced into the ring is preferably 0 to 3, and particularly preferably 0 to 2. When anisotropy of negative dielectric constant is required to improve optical properties, a ring structure (difluorophenyl structure) in which two fluorine atoms adjacent to one benzene ring are introduced is included in the molecular structure Preferably there is. A compound having a difluorophenyl structure is also preferred when it is necessary to lower the melting point while keeping the upper limit temperature of the smectic C phase high. Further, in order to keep the melting point low and the viscosity low and thus keep the response speed high, it is preferable to use a bicyclic compound, and the proportion of the bicyclic compound is 20% or more of the entire ferroelectric liquid crystal composition. It is preferably 30% or more, more preferably 40% or more. On the other hand, in order to maintain the stability of the smectic C phase and keep the maximum temperature high, it is preferable to use a tricyclic compound. In order to lower the melting point, it is preferable to select and mix compounds having different structures.
Moreover, it is also preferable to contain the compound of general formula (IV-a) in addition to the compound of general formula (II) for further expansion of a temperature range, especially expansion of a low temperature region.

（Ｒ^４１は炭素原子数１〜１８の直鎖状又は分岐状のアルキル基を表し、該アルキル基中の、１つ又は２つの隣接していない−ＣＨ_２−基は−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯ−Ｏ−、−Ｏ−ＣＯ−、−ＣＯ−Ｓ−、−Ｓ−ＣＯ−、−Ｏ−ＣＯ−Ｏ−、−ＣＨ＝ＣＨ−、−Ｃ≡Ｃ−、シクロプロピレン基又は−Ｓｉ（ＣＨ_３）_２−で置き換えられてもよく、該アルキル基中の１つ又はそれ以上の水素原子はフッ素原子あるいはＣＮ基で置き換えられていてもよく、Ａ^４、Ｂ^４及びＣ^４は各々独立に１つ又は２つの水素原子がフッ素原子、ＣＦ_３基、ＯＣＦ_３基、又はＣＮ基、あるいはこれらの複数の基で置き換えられてもよい１，４−フェニレン基、１つ又は２つの水素原子がフッ素原子で置換されていてもよいピラジン−２，５−ジイル基、ピリダジン−３，６−ジイル基、ピリジン−２，５−ジイル基、ピリミジン−２，５−ジイル基、１つ又は２つの水素原子がシアノ基あるいはメチル基あるいはその両方で置き換えられてもよいトランス−１，４−シクロへキシレン基、又は、１，３，４−チアジアゾール−２，５−ジイル基、１，３−ジオキサン−２，５−ジイル基、１，３−ジチアン−２，５−ジイル基、１，３−チアゾール−２，４−ジイル基、１，３−チアゾール−２，５−ジイル基、チオフェン−２，４−ジイル基、チオフェン−２，５−ジイル基、ピペラジン−１，４−ジイル基、ピペラジン−２，５−ジイル基、ナフタレン−２，５−ジイル基を表し、Ｌ^４１、及びＬ^４２は各々独立に単結合、−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、−ＣＯ−Ｏ−、−Ｏ−ＣＯ−、−ＣＯ−Ｓ−、−Ｓ−ＣＯ−、−Ｏ−ＣＯ−Ｏ−、−ＣＨ_２ＣＨ_２−、−ＣＨ＝ＣＨ−又は−Ｃ≡Ｃ−を表し、ａ^４、ｂ^４、及びｃ^４は０又は１を表し、ａ^４、ｂ^４及びｃ^４の合計は２又は３を表し、Ｘ^４は一般式（ＩＶ−ｂ）

(R ⁴¹ represents a linear or branched alkyl group having 1 to 18 carbon atoms, and one or two non-adjacent —CH ₂ — groups in the alkyl group are —O—, —S. -, -CO-, -CO-O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH = CH-, -C≡C-, A cyclopropylene group or —Si (CH ₃ ) ₂ — may be substituted, and one or more hydrogen atoms in the alkyl group may be substituted with a fluorine atom or a CN group, and A ⁴ , B ⁴ and C ⁴ are each independently a 1,4-phenylene group in which one or two hydrogen atoms may be replaced by a fluorine atom, a CF ₃ group, an OCF ₃ group, or a CN group, or a plurality of these groups, One or two hydrogen atoms may be substituted with fluorine atoms, pyrazine-2,5- Diyl group, pyridazine-3,6-diyl group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, one or two hydrogen atoms are replaced by cyano group or methyl group or both Trans-1,4-cyclohexylene group, or 1,3,4-thiadiazole-2,5-diyl group, 1,3-dioxane-2,5-diyl group, 1,3-dithian-2 , 5-diyl group, 1,3-thiazole-2,4-diyl group, 1,3-thiazole-2,5-diyl group, thiophene-2,4-diyl group, thiophene-2,5-diyl group, Represents piperazine-1,4-diyl group, piperazine-2,5-diyl group, naphthalene-2,5-diyl group, and L ⁴¹ and L ⁴² each independently represents a single bond, —O—, —S—, _{-CO -, - CH 2 O -} , - O _{H 2 -, - CF 2 O} -, - OCF 2 -, - CO-O -, - O-CO -, - CO-S -, - S-CO -, - O-CO-O -, - CH 2 CH ₂ —, —CH═CH— or —C≡C— is represented, a ⁴ , b ⁴ , and c ⁴ represent 0 or 1, and the sum of a ⁴ , b ^4, and c ⁴ represents 2 or 3 , X ⁴ represents the general formula (IV-b)

（式中、Ｒ^４２は単結合又は炭素原子数１〜１８の直鎖状又は分岐状のアルキレン基を表し、該アルキレン基中の１つ又は２つの隣接していない−ＣＨ_２−基は−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯ−Ｏ−、−Ｏ−ＣＯ−、−ＣＯ−Ｓ−、−Ｓ−ＣＯ−、−Ｏ−ＣＯ−Ｏ−、−ＣＨ＝ＣＨ−、−Ｃ≡Ｃ−、シクロプロピレン基又は−Ｓｉ（ＣＨ_３）_２−で置き換えられてもよく、さらにアルキレン基の１つ又はそれ以上の水素原子がフッ素原子あるいはＣＮ基で置き換えられていてもよい。）
又は、一般式（ＩＶ−ｃ）

(Wherein R ⁴² represents a single bond or a linear or branched alkylene group having 1 to 18 carbon atoms, and one or two non-adjacent —CH ₂ — groups in the alkylene group are — O-, -S-, -CO-, -CO-O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH = CH-,- C≡C—, a cyclopropylene group, or —Si (CH ₃ ) ₂ — may be substituted, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a CN group. )
Or general formula (IV-c)

（ただし、Ｒ^４３は単結合又は炭素原子数１〜１８の直鎖状又は分岐状のアルキレン基を表し、該アルキレン基中の１つ又は２つの隣接していない−ＣＨ_２−基は−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯ−Ｏ−、−Ｏ−ＣＯ−、−ＣＯ−Ｓ−、−Ｓ−ＣＯ−、−Ｏ−ＣＯ−Ｏ−、−ＣＨ＝ＣＨ−又は−Ｃ≡Ｃ−で置き換えられてもよく、Ｒ^４４、Ｒ^４５及びＲ^４６は各々独立に水素原子又は炭素原子数１〜１８の直鎖状又は分岐状のアルキル基を表し、該アルキル基中の１つの隣接していない−ＣＨ_２−基は−Ｏ−、−ＣＯ−Ｏ−、−Ｏ−ＣＯ−、−ＣＨ＝ＣＨ−又は−Ｃ≡Ｃ−に置き換えられてもよい。）を表す。）
一般式（ＩＶ−ａ）で表される化合物としては、下記に示す化合物、

(However, R ⁴³ represents a single bond or a linear or branched alkylene group having 1 to 18 carbon atoms, and one or two non-adjacent —CH ₂ — groups in the alkylene group are —O -, -S-, -CO-, -CO-O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH = CH- or -C. R ⁴⁴ , R ⁴⁵ and R ⁴⁶ each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms, and 1 in the alkyl group Two non-adjacent —CH ₂ — groups may be replaced by —O—, —CO—O—, —O—CO—, —CH═CH— or —C≡C—. )
Examples of the compound represented by the general formula (IV-a) include the following compounds:

（式中、Ｙ^４及びＺ^４のいずれか一方は炭素数１〜２２の直鎖あるいは分岐のアルキル鎖であって、１個の−ＣＨ_２−基が、−Ｏ−、シクロプロピレン基、−ＣＨ＝ＣＨ−、−ＣＯＯ−又は−Ｓｉ（ＣＨ_３）_２−で置き換えられていてもよく、他の一方は、

(In the formula, any one of Y ⁴ and Z ⁴ is a linear or branched alkyl chain having 1 to 22 carbon atoms, and one —CH ₂ — group is —O—, cyclopropylene group, — May be replaced by CH═CH—, —COO— or —Si (CH ₃ ) ₂ —,

（ここで、Ｒ^４２０は、単結合、−ＣＯＯ−、−ＯＣＯ−、−ＯＣＯ−Ｃ_ｔＨ_２ｔ＋１−又は−Ｏ−Ｃ_ｔＨ_２ｔ＋１−（ｔは１から１０の整数）である）、又は、下記の化合物

Where R ⁴²⁰ is a single bond, —COO—, —OCO—, —OCO—C _t H _{2t + 1} — or —O—C _t H _{2t + 1} — (t is an integer from 1 to 10), or The following compounds

（式中、Ｓ^４及びＴ^４のいずれか一方は炭素数１〜２２の直鎖あるいは分岐のアルキル鎖であって、１個の−ＣＨ_２−基が、−Ｏ−、シクロプロピレン基、−ＣＨ＝ＣＨ−、−ＣＯＯ−又は−Ｓｉ（ＣＨ_３）_２−で置き換えられていてもよく、他の一方は下記一般式（ＩＶ−ｃ）、

(In the formula, any one of S ⁴ and T ⁴ is a linear or branched alkyl chain having 1 to 22 carbon atoms, and one —CH ₂ — group is —O—, cyclopropylene group, — CH═CH—, —COO— or —Si (CH ₃ ) ₂ — may be substituted, and the other one is represented by the following general formula (IV-c),

（ただし、Ｒ^４３は単結合又は炭素原子数１〜１８の直鎖状又は分岐状のアルキレン基を表し、該アルキレン基中の１つ又は２つの隣接していない−ＣＨ_２−基は−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯ−Ｏ−、−Ｏ−ＣＯ−、−ＣＯ−Ｓ−、−Ｓ−ＣＯ−、−Ｏ−ＣＯ−Ｏ−、−ＣＨ＝ＣＨ−又は−Ｃ≡Ｃ−で置き換えられてもよく、Ｒ^４４、Ｒ^４５及びＲ^４６は各々独立に水素原子又は炭素原子数１〜１８の直鎖状又は分岐状のアルキル基を表し、該アルキル基中の１つの隣接していない−ＣＨ_２−基は−Ｏ−、−ＣＯ−Ｏ−、−Ｏ−ＣＯ−、−ＣＨ＝ＣＨ−又は−Ｃ≡Ｃ−に置き換えられてもよい。）を表す。）が好ましく用いられる。
より具体的には次の構造を持つ化合物が好ましい。

(However, R ⁴³ represents a single bond or a linear or branched alkylene group having 1 to 18 carbon atoms, and one or two non-adjacent —CH ₂ — groups in the alkylene group are —O -, -S-, -CO-, -CO-O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH = CH- or -C. R ⁴⁴ , R ⁴⁵ and R ⁴⁶ each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms, and 1 in the alkyl group Two non-adjacent —CH ₂ — groups may be replaced by —O—, —CO—O—, —O—CO—, —CH═CH— or —C≡C—. ) Is preferably used.
More specifically, a compound having the following structure is preferred.

（式中、ｎとｍは、それぞれ独立に５〜１１を示す）
これら化合物の中で環Ａ^４、環Ｂ^４、環Ｃ^４がフェニル基あるいはシクロヘキシル基である場合には、化合物の持つ分極性が低いため、その含有量を増やしてもＴＦＴ駆動には影響を与えない面で好ましい。液晶の温度範囲を広げ、融点を低下させるという面では、ピリジン環、ピリミジン環等の複素環を有する化合物を使うことが良いが、その場合には化合物の持つ分極性が比較的大きいため、ＴＦＴ駆動に悪影響を与えない含有量以下で使用することが好ましい。
強誘電性液晶組成物の強誘電性を発現するためのキラル成分としては、公知慣用のキラル化合物を用いることができる。キラル化合物としては不斉原子を持つ化合物、あるいは軸不斉を持つ化合物を用いることが好ましく、さらに、不斉炭素を持つ化合物、あるいは炭素−炭素結合を軸とした不斉を持つ化合物を用いることが好ましい。不斉炭素は鎖状構造の一部に導入されていても、環状構造の一部に導入されていても良い。不斉炭素としては、炭素上にフッ素原子、メチル基、ＣＦ３基が導入されているのもが好ましく、また特に、一般式（Ｖ−ａ）、あるいは、一般式（Ｖ−ｅ）で表される化合物の環構造としては具体的には次の構造を持つことが好ましい。

(In the formula, n and m each independently represent 5 to 11)
Among these compounds, when ring A ⁴ , ring B ⁴ , or ring C ⁴ is a phenyl group or a cyclohexyl group, the polarizability of the compound is low, so even if the content is increased, TFT driving is affected. It is preferable in terms of not giving. In terms of expanding the temperature range of the liquid crystal and lowering the melting point, it is preferable to use a compound having a heterocyclic ring such as a pyridine ring or a pyrimidine ring. It is preferable to use at a content below that does not adversely affect driving.
As the chiral component for expressing the ferroelectricity of the ferroelectric liquid crystal composition, known and commonly used chiral compounds can be used. As the chiral compound, a compound having an asymmetric atom or a compound having axial asymmetry is preferably used, and a compound having an asymmetric carbon or a compound having an asymmetry around a carbon-carbon bond is used. Is preferred. The asymmetric carbon may be introduced into a part of the chain structure or may be introduced into a part of the cyclic structure. As the asymmetric carbon, it is preferable that a fluorine atom, a methyl group, or a CF3 group is introduced on the carbon. In particular, the asymmetric carbon is represented by the general formula (Va) or (Ve). Specifically, the ring structure of the compound preferably has the following structure.

一般式（Ｖ−ｅ）の不斉構造として具体的には下記構造のものが好ましい。

Specifically, the following structure is preferable as the asymmetric structure of the general formula (Ve).

（式中、ｓは１〜４の整数を表し、ｒは１〜１０の整数を表し、Ｑ_３は炭素数３〜８のアルキル基を表し、Ｑ_４は炭素数２〜１０のアルキル基を表し、Ｑ_５は炭素数１〜１０のアルキル基を表し、Ｑ_６は炭素数１〜４のアルキル基を表す。）
一般式（Ｖ−ａ）の化合物としては下記構造のものが特に好ましく用いられる。

(In the formula, s represents an integer of 1 to 4, r represents an integer of 1 to 10, Q ₃ represents an alkyl group having 3 to 8 carbon atoms, and Q ₄ represents an alkyl group having 2 to 10 carbon atoms. represents, _{Q 5} represents an alkyl group having 1 to 10 carbon atoms, _{Q 6} represents an alkyl group having 1 to 4 carbon atoms.)
As the compound of the general formula (Va), those having the following structures are particularly preferably used.

（式中、Ｒ_ａａは炭素数１〜１８の直鎖状あるいは分岐状のアルキル基又はアルコキシ基、Ｒ_ｂｂは炭素数１〜１８の直鎖状あるいは分岐状のアルキル基、Ｍ_ａａは炭素数１〜３のメチレン基、Ｍ_ｂｂは炭素数１〜２のメチレン基を表す。）

(Wherein R _aa is a linear or branched alkyl group or alkoxy group having 1 to 18 carbon atoms, R _bb is a linear or branched alkyl group having 1 to 18 carbon atoms, and M _aa is the number of carbon atoms. 1 to 3 methylene groups, and M _bb represents a methylene group having 1 to 2 carbon atoms.)

Among these optically active compounds, when ring A ⁵ , ring B ⁵ , ring C ⁵ , ring A ⁶ , ring B ⁶ , or ring C ⁶ is a phenyl group or a cyclohexyl group, the polarizability of the compound is low. It is most preferable in terms of not affecting the TFT driving even if the content is increased. In terms of expanding the temperature range of the liquid crystal and lowering the melting point, it is preferable to use a compound having a heterocyclic ring such as a pyridine ring or a pyrimidine ring. It is preferable to use at a content below that does not adversely affect driving.

  In order to obtain a large spontaneous polarization, s = 1 to 3 is preferable, and s = 1 is particularly preferable. In order to suppress crystallization, it is preferable to use a compound having two rings. In order to increase the stability (maximum temperature) of the ferroelectric phase, the effect of suppressing crystallization is maintained. It is preferable to use a compound having three rings in the range. In order to obtain good orientation, it is important to increase the helical pitch of the chiral nematic phase, in particular, to increase the helical pitch of the chiral nematic phase during the transition between the nematic phase and the smectic phase. Therefore, when the amount of (Va) added increases and the helical pitch of the chiral nematic phase during the transition between the nematic phase and the smectic phase becomes short enough to disturb the orientation, the compound of (Va) It is preferable to increase the helical pitch of the chiral nematic phase by using in addition to (Va) a chiral compound having an effect of inducing sense opposite to the chirality (sense) of the induced chiral nematic phase. There is no particular limitation on the use of the chiral compound at this time, and a known and commonly used chiral compound can be used. However, a compound having the same polarity of spontaneous polarization as that used (Va) or a value of spontaneous polarization was used. A compound that is sufficiently smaller than (Va) is preferable because it can suppress a decrease due to cancellation of spontaneous polarization.

  In the ferroelectric phase, when orientation is performed using the surface stabilization effect, it is preferable that the helical pitch in the ferroelectric phase is long. In this case, the ferroelectric phase is induced by the compound (Va). It is preferable to increase the helical pitch of the ferroelectric phase by using, in addition to (Va), a chiral compound that has an effect of inducing a sense opposite to the palmarity (sense) of the ferroelectric phase. There is no particular limitation on the use of the chiral compound at this time, and a known and commonly used chiral compound can be used. However, a compound having the same polarity of spontaneous polarization as that used (Va) or a value of spontaneous polarization was used. A compound that is sufficiently smaller than (Va) is preferable because it can suppress a decrease due to cancellation of spontaneous polarization. When the polymer stabilizing effect is simply used without using the surface stabilizing effect, it is not particularly necessary to add a chiral compound having such an effect of inducing reverse sense to (Va). When used in a relatively thick cell thickness (3 μm or more), the polymer stabilization process or the state after the polymer stabilization is improved, the mobility of the liquid crystal molecules is increased and the polymer stabilization process is facilitated. If a short helical pitch is required to facilitate the development of gray scale after polymer stabilization, it is preferable to add a chiral compound with a short helical pitch of the ferroelectric phase . There is no particular limitation on the use of the chiral compound used at the time of addition, and a known and conventional chiral compound can be used. However, the compound having the same polarity of spontaneous polarization as (Va) used, or the value of spontaneous polarization Is preferably a compound that is sufficiently smaller than the (Va) used because it can suppress a decrease due to cancellation of spontaneous polarization. As an additive, it is more preferable to select a chiral compound that has a sufficiently long helical pitch induced in the chiral nematic liquid crystal or that can cancel the helical pitch induced in (Va).

<Polymerizable liquid crystal compound (III)>
The polymerizable liquid crystal compound (III) used in the polymer-stabilized liquid crystal composition of the present invention has the following general formula (III-a):

(In formula (III-a), R ³ and R ⁴ each independently represent a hydrogen atom or a methyl group,
C ⁴ and C ⁵ are each independently 1,4-phenylene group, 1,4-cyclohexylene group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, pyridazine-3,6- Diyl group, 1,3-dioxane-2,5-diyl group, cyclohexene-1,4-diyl group, decahydronaphthalene-2,6-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6 -Diyl group, 2,6-naphthylene group or indane-2,5-diyl group (among these groups 1,4-phenylene group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, The 2,6-naphthylene group and indan-2,5-diyl group are unsubstituted or have one fluorine atom, chlorine atom, methyl group, trifluoromethyl group or trifluoromethoxy group as a substituent. May have two or more.) Represent,
Z ³ and Z ⁵ are each independently a single bond or an alkylene group having 1 to 15 carbon atoms (one or two or more methylene groups present in the alkylene group are such that oxygen atoms are not directly bonded to each other) Each independently may be substituted with an oxygen atom, -CO-, -COO- or -OCO-, and one or more hydrogen atoms present in the alkylene group are each independently a fluorine atom, Which may be substituted with a methyl group or an ethyl group)
Z ⁴ is a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —CH ₂ CH ₂ O—, —OCH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ O—, _{-OCH 2 CH 2 CH 2 -,} - CH 2 CH 2 OCO -, - COOCH 2 CH 2 -, - CH 2 CH 2 COO -, - OCOCH 2 CH 2 -, - CH = CH -, - C≡C- _{, -CF 2 O -, - OCF} 2 -, - COO- or an -OCO-,
n ² represents 0, 1 or 2. However, when n ² represents 2, a plurality of C ⁴ and Z ⁴ may be the same or different. ),

  Formula (III-b)

（式（ＩＩＩ−ｂ）中、Ｒ^５及びＲ^６はそれぞれ独立して水素原子又はメチル基を表し、Ｃ^６は１，４−フェニレン基、１，４−シクロへキシレン基、ピリジン−２，５−ジイル基、ピリミジン−２，５−ジイル基、ピリダジン−３，６−ジイル基、１，３−ジオキサン−２，５−ジイル基、シクロヘキセン−１，４−ジイル基、デカヒドロナフタレン−２，６−ジイル基、１，２，３，４−テトラヒドロナフタレン−２，６−ジイル基、２，６−ナフチレン基又はインダン−２，５−ジイル基（これらの基のうち１，４−フェニレン基、１，２，３，４−テトラヒドロナフタレン−２，６−ジイル基、２，６−ナフチレン基及びインダン−２，５−ジイル基は、非置換であるか又は置換基としてフッ素原子、塩素原子、メチル基、トリフルオロメチル基若しくはトリフルオロメトキシ基を１個若しくは２個以上有することができる。）を表し、
Ｃ^７及びＣ^８はそれぞれ独立してベンゼン−１，２，４−トリイル基、ベンゼン−１，３，４−トリイル基、ベンゼン−１，３，５−トリイル基、シクロヘキサン−１，２，４−トリイル基、シクロヘキサン−１，３，４−トリイル基又はシクロヘキサン−１，３，５−トリイル基を表し、Ｚ^６及びＺ^８はそれぞれ独立して単結合又は炭素原子数１から１５のアルキレン基（該アルキレン基中に存在する１個又は２個以上のメチレン基は、酸素原子が相互に直接結合しないものとして、それぞれ独立に酸素原子、−ＣＯ−、−ＣＯＯ−又は−ＯＣＯ−で置換されていても良く、該アルキレン基中に存在する１個又は２個以上の水素原子はそれぞれ独立にフッ素原子、メチル基又はエチル基で置換されていても良い。）を表し、
Ｚ^７及びZ^９それぞれ独立して単結合、−ＣＨ_２ＣＨ_２−、−ＣＨ_２Ｏ−、−ＯＣＨ_２−、−ＣＨ_２ＣＨ_２Ｏ−、−ＯＣＨ_２ＣＨ_２−、−ＣＨ_２ＣＨ_２ＣＨ_２Ｏ−、−ＯＣＨ_２ＣＨ_２ＣＨ_２−、−ＣＨ_２ＣＨ_２ＯＣＯ−、−ＣＯＯＣＨ_２ＣＨ_２−、−ＣＨ_２ＣＨ_２ＣＯＯ−、−ＯＣＯＣＨ_２ＣＨ_２−、−ＣＨ＝ＣＨ−、−Ｃ≡Ｃ−、−ＣＦ_２Ｏ−、−ＯＣＦ_２−、−ＣＯＯ−又は−ＯＣＯ−を表し、
ｎ^３は、０、１又は２を表すが、、ｎ^３が２を表す場合、複数あるＣ^６及びＺ^７は同じであっても異なっていても良く、ｎ^５及びｎ^６はそれぞれ独立して１、２及び３を表す。）
及び一般式（ＩＩＩ−ｃ）

(In formula (III-b), R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group, and C ⁶ represents a 1,4-phenylene group, a 1,4-cyclohexylene group, pyridine-2, 5-diyl group, pyrimidine-2,5-diyl group, pyridazine-3,6-diyl group, 1,3-dioxane-2,5-diyl group, cyclohexene-1,4-diyl group, decahydronaphthalene-2 , 6-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, 2,6-naphthylene group or indane-2,5-diyl group (among these groups, 1,4-phenylene Group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, 2,6-naphthylene group and indan-2,5-diyl group are unsubstituted or substituted with fluorine atom, chlorine Atom, methyl group, trif The Oromechiru group or a trifluoromethoxy group may have one or two or more.) Represent,
C ⁷ and C ⁸ are each independently benzene-1,2,4-triyl group, benzene-1,3,4-triyl group, benzene-1,3,5-triyl group, cyclohexane-1,2,4. -Represents a triyl group, a cyclohexane-1,3,4-triyl group or a cyclohexane-1,3,5-triyl group, Z ⁶ and Z ⁸ are each independently a single bond or an alkylene group having 1 to 15 carbon atoms. (One or two or more methylene groups present in the alkylene group are each independently substituted with an oxygen atom, —CO—, —COO— or —OCO—, assuming that the oxygen atoms are not directly bonded to each other. And one or two or more hydrogen atoms present in the alkylene group may each independently be substituted with a fluorine atom, a methyl group or an ethyl group).
Z ⁷ and Z ⁹ are each independently a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —CH ₂ CH ₂ O—, —OCH ₂ CH ₂ —, —CH ₂ CH _{2. CH 2 O -, - OCH 2} CH 2 CH 2 -, - CH 2 CH 2 OCO -, - COOCH 2 CH 2 -, - CH 2 CH 2 COO -, - OCOCH 2 CH 2 -, - CH = CH-, _{-C≡C -, - CF 2 O -} , - OCF 2 -, - COO- or an -OCO-,
n ³ represents 0, 1 or 2, but when n ³ represents 2, a plurality of C ⁶ and Z ⁷ may be the same or different, and n ⁵ and n ⁶ are each independently 1, 2 and 3 are represented. )
And general formula (III-c)

(In formula (III-c), R ⁷ represents a hydrogen atom or a methyl group,
6-membered rings T ¹ , T ² and T ³ are each independently

(Where m represents an integer of 1 to 4),
n ⁴ represents an integer of 0 or 1,
Y ¹ and Y ² are each independently a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —COO—, —OCO—, —C≡C—, —CH═CH—. , —CF═CF—, — (CH ₂ ) ₄ —, —CH ₂ CH ₂ CH ₂ O—, —OCH ₂ CH ₂ CH ₂ —, —CH ₂ ═CHCH ₂ CH ₂ — or —CH ₂ CH ₂ CH = CH-
Y ³ represents a single bond, —COO—, or —OCO—,
R ⁸ represents a hydrocarbon group having 1 to 18 carbon atoms. At least one polymerizable compound (III) selected from the group consisting of:
More specifically, general formulas (III-d) and (III-e)

(In the formulas (III-d) and (III-e), m ¹ represents 0 or 1,
Y ¹¹ and Y ¹² each independently represent a single bond, —O—, —COO— or —OCO—,
Y ¹³ and Y ¹⁴ each independently represent —COO— or —OCO—,
Y ¹⁵ and Y ¹⁶ each independently represent —COO— or —OCO—,
r and s each independently represent an integer of 2 to 14. The 1,4-phenylene group present in the formula may be unsubstituted or have one or more fluorine, chlorine, methyl, trifluoromethyl or trifluoromethoxy groups as substituents. it can. It is preferable to use a compound represented by any one of (2), since an optically anisotropic body excellent in mechanical strength and heat resistance can be obtained.

  Specific examples of the compound represented by the general formula (III-a) can include the following (III-1) to (III-11).

(Wherein j and k each independently represents an integer of 2 to 14)
Specific examples of the compound represented by any one of the general formulas (III-d) and (III-e) can be given in the following (III-12) to (III-21).

(Wherein j and k each independently represents an integer of 2 to 14)
Specific examples of the compound represented by the general formula (III-b) can be listed in the following (III-30) and (III-31).

（式中、ｊ及びｋはそれぞれ独立的に２〜１４の整数を表す。）

(Wherein j and k each independently represents an integer of 2 to 14)

<Polymerization method of polymer stabilized liquid crystal composition>
As a polymerization method for polymerizing the composition for a polymer-stabilized liquid crystal display element of the present invention, radical polymerization, anion polymerization, cationic polymerization, and the like can be used, but polymerization is preferably performed by radical polymerization.

As the radical polymerization initiator, a thermal polymerization initiator or a photopolymerization initiator can be used, but a photopolymerization initiator is preferable. Specifically, the following compounds are preferable.
Diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- ( 2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl-phenylketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl- Acetophenone series such as 2-dimethylamino-1- (4-morpholinophenyl) -butanone;

Benzoins such as benzoin, benzoin isopropyl ether and benzoin isobutyl ether;
Acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide;
Benzyl, methylphenylglyoxyesters;
Benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4,4′-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4′-methyl-diphenyl sulfide, acrylated benzophenone, 3,3 ′, 4,4 ′ -Benzophenone series such as tetra (t-butylperoxycarbonyl) benzophenone, 3,3'-dimethyl-4-methoxybenzophenone;
Thioxanthone systems such as 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone;
Aminobenzophenone series such as Michler's ketone and 4,4′-diethylaminobenzophenone;
10-butyl-2-chloroacridone, 2-ethylanthraquinone, 9,10-phenanthrenequinone, camphorquinone and the like are preferable. Of these, benzyldimethyl ketal is most preferred.

<Composition ratio of polymer-stabilized ferroelectric liquid crystal composition>
The polymer-stabilized ferroelectric liquid crystal composition of the present invention comprises a liquid crystal compound represented by compound (II), and a polymerizable compound represented by polymerizable compound (I) and polymerizable compound (III). Is done. The composition ratio between the liquid crystal compound and the polymerizable compound has an optimum composition ratio because if the composition ratio of the polymerizable compound is too large, the characteristics as the polymer-stabilized ferroelectric liquid crystal composition are impaired. Specifically, the polymerizable compound is preferably 0.1% to 8%, more preferably 1% to 8%, and particularly preferably 2% to 6%.
In the polymer-stabilized ferroelectric liquid crystal composition of the present invention, the content of the polymerizable compound (III) is 0.05% to 7%, and the polymerizable compound (III) and the polymerizable compound (I And (III) :( I) = 1: 1 to 49: 1.

  As the liquid crystal composition, the content of the compound represented by the general formula (II) is preferably 5 to 90%, more preferably 10% to 85%, and particularly preferably 20% to 80%.

These liquid crystal compositions may be subjected to a purification treatment with silica, alumina or the like for the purpose of removing impurities or the like or further increasing the specific resistance value. The specific resistance value is preferably 10 ¹² Ω · cm or more, and more preferably 10 ¹³ Ω · cm or more. Furthermore, dopants such as chiral compounds, dyes, and ion scavengers can be added to the liquid crystal composition according to the purpose.

  In addition, antioxidants, UV absorbers, non-reactive oligomers and inorganic fillers, organic fillers, polymerization inhibitors, antifoaming agents, leveling agents, plasticizers, silane coupling agents, etc. are added as necessary. You may do it.

  The polymer-stabilized ferroelectric liquid crystal composition of the present invention comprises a liquid crystal compound represented by compound (II), and a polymerizable compound represented by polymerizable compound (I) and polymerizable compound (III). However, when the polymer-stabilized ferroelectric liquid crystal composition is polymerized, it preferably contains a polymerization initiator. When the polymerization initiator is contained, the content other than the polymerization initiator is preferably 98% to 99.9%, and the polymerization initiator is preferably 0.1% to 2%.

In the present invention, a polyfunctional liquid crystalline monomer may be added in addition to the polymerizable liquid crystal compound (III). As this polyfunctional liquid crystalline monomer, acryloyloxy group, methacryloyloxy group, acrylamide group, methacrylamide group, epoxy group, vinyl group, vinyloxy group, ethynyl group, mercapto group, maleimide group, ClCH = _{CHCONH-, CH 2 = CCl-, CHCl} = CH-, RCH = CHCOO- ( wherein R is chlorine, fluorine, or a hydrocarbon group having 1 to 18 carbon atoms), but can be exemplified acryloyl among these An oxy group, a methacryloyloxy group, an epoxy group, a mercapto group, and a vinyloxy group are preferable, a methacryloyloxy group or an acryloyloxy group is particularly preferable, and an acryloyloxy group is most preferable.

As the molecular structure of the polyfunctional liquid crystalline monomer, there are at least two liquid crystal skeletons having two or more ring structures, a polymerizable functional group, and a flexible group for connecting the liquid crystal skeleton and the polymerizable functional group. Those having three flexible groups are more preferable. Examples of the flexible group include an alkylene spacer group represented by — (CH ₂ ) _n — (where n represents an integer) or — (Si (CH ₃ ) ₂ —O) _n — (where n is A siloxane spacer group represented by the formula (4), and an alkylene spacer group is preferred. Bonds such as —O—, —COO—, and —CO— may be present in the bonding portion between these flexible groups and the liquid crystal skeleton or polymerizable functional group.

  The liquid crystal skeleton can be used without particular limitation as long as it is generally recognized as a liquid crystal skeleton (mesogen) in this technical field, but those having at least two or more ring structures are preferable. The ring that can be used as the ring structure is benzene, pyridine, pyrazine, pyridazine, pyrimidine, 1,2,4-triazine, 1,3,5-triazine, tetrazine, dihydrooxazine, cyclohexane, cyclohexene, cyclohexadiene, cyclohexanone, piperidine , Piperazine, tetrahydropyran, dioxane, tetrahydrothiopyran, dithiane, oxathiane, dioxaborinane, naphthalene, dioxanaphthalene, tetrahydronaphthalene, quinoline, coumarin, quinoxaline, decahydronaphthalene, indane, benzoxazole, benzothiazole, phenanthrene, dihydrophenance Len, perhydrophenanthrene, dioxaperhydrophenanthrene, fluorene, fluorenone, cycloheptane, cyclohexane Tatrienone, cholesterol, bicyclo [2.2.2] octane, bicyclo [2.2.2] octene, 1,5-dioxaspiro (5.5) undecane, 1,5-dithiaspiro (5.5) undecane, triphenylene, Examples include torquesen, porphyrin, and phthalocyanine. Among these, benzene, cyclohexane, phenanthrene, naphthalene, tetrahydronephthalene, and decahydronephthalene are preferable. One or more of these rings may be substituted with an alkyl group having 1 to 7 carbon atoms, an alkoxy group, an alkanoyl group, a cyano group, or a halogen atom. As the alkyl group, a methyl group, an ethyl group, an n-propyl group, and an n-butyl group are desirable, and a methyl group and an ethyl group are particularly preferable. As an alkoxy group, a methoxy group, an ethoxy group, a propoxy group, and a butoxy group are preferable. As an alkanoyl group, an acetyl group, a propionyl group, and a butyroyl group are preferable. As a halogen atom, a fluorine atom, a bromine atom, and a chlorine atom are preferable. A fluorine atom and a chlorine atom are particularly preferable. In addition to the polyfunctional liquid crystalline monomer, a monofunctional liquid crystalline monomer may be added.

<Liquid crystal display element>
The liquid crystal display element of the present invention is a polymer-stabilized liquid crystal display element in which a low-molecular liquid crystal is fixed in the form of nanoparticles dispersed in a liquid crystal, or a high-order liquid crystal display element in which a three-dimensional network polymer chain is formed in the liquid crystal. A molecule-stabilized liquid crystal display device, wherein the polymer has a low-molecular liquid crystal dispersion structure, and the polymer-stabilized ferroelectric liquid crystal composition according to the present invention described above is exposed to ultraviolet rays to align the low-molecular liquid crystal with a polymer. Stabilized.

When the polymer-stabilized ferroelectric liquid crystal composition is exposed to ultraviolet light, it is preferably exposed to ultraviolet light while applying an alternating current to the polymer-stabilized ferroelectric liquid crystal composition.
Moreover, it is preferable to expose to ultraviolet rays while applying an alternating current at a temperature at which the liquid crystal phase of the low molecular liquid crystal exhibits a chiral smectic C phase. The alternating current to be applied is preferably an alternating current having a frequency of 500 Hz to 10 kHz, and more preferably a rectangular wave having a frequency of 1 kHz to 10 kHz.

More preferably, UV exposure is performed while applying a rectangular wave having a frequency of 1 kHz to 10 kHz at a voltage ± 15 V or less at a temperature at which the liquid crystal phase of the low-molecular liquid crystal exhibits a chiral smectic C phase.
More preferably, when the phase transition temperature between the smectic A phase and the chiral smectic C phase exhibited by the polymer-stabilized ferroelectric liquid crystal composition is T (° C.), it is (T-40) ° C. or more and (T + 5) ° C. or less. In addition, it is desirable that the polymer-stabilized liquid crystal composition is exposed to ultraviolet rays while applying an alternating current at a temperature of 35 ° C. or higher.
In ultraviolet exposure, it is desirable to expose ultraviolet rays of 1000 mJ / cm ² or more.

  The liquid crystal display element of the present invention can be applied to a liquid crystal display element driven by an active element such as a thin film transistor element, a metal insulator metal element, or a thin film diode element. In particular, when the auxiliary capacitor Cs is connected in parallel between the active element and the liquid crystal pixel electrode, and the liquid crystal pixel electrode is Cflc, Cs / Cfls is preferably 0.1 or more and 3 or less. In addition, a liquid crystal display element driven by a field sequential method is preferable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited only to these Examples. Unless otherwise specified, “%” means “mass%”.

(Production and evaluation method of polymer-stabilized liquid crystal display element)
The polymer-stabilized liquid crystal display elements in the examples were produced by the following method.
The polymer-stabilized ferroelectric liquid crystal composition was heated above the chiral nematic phase transition and injected by vacuum injection. As the cell, an alignment cell of parallel rubbing with ITO coated with a polyimide alignment film having a cell gap of 2 μm was used so that the liquid crystal was uniaxially aligned (homogeneous alignment).

A light control layer forming material comprising a liquid crystal composition, a radical polymerizable composition, a photopolymerization initiator, and a small amount of a polymerization inhibitor was injected into the glass cell by a vacuum injection method. The degree of vacuum was set to be 2 Pascals. After the injection, the glass cell was taken out and the inlet was sealed with a sealing agent 3026E (manufactured by ThreeBond). After confirming the uniaxial orientation with a crossed Nichols polarizing microscope, a quartz glass is passed through an ultraviolet cut filter L-37 (manufactured by Hoya Candeo Optronics Co., Ltd.) while switching by applying a rectangular wave of 5 V at a frequency of 2 KHz. The liquid crystal cell installed on the microscope stage was guided by UV light and exposed. Stabilize the polymer content by irradiating a metal halide lamp adjusted so that the irradiation intensity of the cell sample surface is 5 mW / cm ² for 300 seconds to polymerize the polymerizable compound of the polymer-stabilized ferroelectric liquid crystal composition. A liquid crystal display element was obtained.

  The previously applied voltage was turned off, and the alignment state after UV exposure was observed with a polarizing microscope to examine whether the bent orientation obtained by applying the voltage was maintained in the absence of an electric field due to polymer stabilization. Furthermore, the transmittance was compared by applying 8 V to the polymer-stabilized cell placed on the microscope stage so that the rubbing direction of the liquid crystal cell was 45 degrees with respect to the polarization direction on the light incident side. The transmittance was 0% when the two polarizing plates were orthogonal, and 100% when they were parallel.

(Adjustment of polymer-stabilized ferroelectric liquid crystal composition)
A polymer-stabilized ferroelectric liquid crystal composition was prepared by blending at least one ferroelectric liquid crystal composition and compound groups (I) and (III) as monomer components. The structure and ratio of each component of the ferroelectric liquid crystal composition (FLC-1) are as follows.

強誘電性液晶組成物（ＦＬＣ−１）と化合物群（Ｉ）及び（ＩＩＩ）をそれぞれ少なくとも一種以上モノマー成分として配合し、高分子安定化強誘電性液晶組成物を調整した（ＭＦＬＣ−１）。高分子安定化強誘電性液晶組成物（ＭＦＬＣ−１）の各成分の構造あるいは内容と割合は下記のとおりである。

Ferroelectric liquid crystal composition (FLC-1) and compound groups (I) and (III) were blended as at least one monomer component to prepare a polymer-stabilized ferroelectric liquid crystal composition (MFLC-1). . The structure, content, and ratio of each component of the polymer-stabilized ferroelectric liquid crystal composition (MFLC-1) are as follows.

ここで、化合物（Ｉ−Ａ）は一般式（Ｉ）より選ばれた非液晶性モノマーであり、（ＩＩＩ−Ａ）、及び（ＩＩＩ−Ｂ）は一般式（ＩＩＩ）より選ばれた液晶性モノマーである。
（実施例１）
このようにして作製した高分子安定化強誘電性液晶組成物（ＭＦＬＣ−１）について、上述の高分子安定化液晶表示素子の作成方法によって高分子安定化強誘電性液晶組成物中のアクリレート化合物を重合させて液晶表示素子を作製した。このようにして得られた表示素子は室温で安定なＶ型のスイッチング挙動を示し、透過率５０％の時の印加電圧（Ｖｒ５０）は４０℃で３Ｖ，２０℃で３Ｖ，０℃で３Ｖと低い値で、かつ温度依存性が少ない良好なものであった。また、２０℃で直流電界を印加して測定したチルト角は２０°と大きいものであった。
（比較例１）
モノマー組成物として一般式（Ｉ）で表される化合物を含まないこと以外は実施例と同様に強誘電性液晶組成物（ＦＬＣ−１）、（ＩＩＩ−Ａ）、（ＩＩＩ−Ｂ）及びイルガキュア６５１を下記の割合で混合し、比較用高分子安定化強誘電性液晶組成物（ＭＦＬＣ−Ｃ１）を作製した。

Here, compound (IA) is a non-liquid crystalline monomer selected from general formula (I), and (III-A) and (III-B) are liquid crystal selected from general formula (III). Monomer.
Example 1
For the polymer-stabilized ferroelectric liquid crystal composition (MFLC-1) thus prepared, the acrylate compound in the polymer-stabilized ferroelectric liquid crystal composition by the above-described method for preparing a polymer-stabilized liquid crystal display element Was polymerized to produce a liquid crystal display element. The display element thus obtained exhibits a V-type switching behavior that is stable at room temperature, and the applied voltage (Vr50) when the transmittance is 50% is 3 V at 40 ° C., 3 V at 20 ° C., and 3 V at 0 ° C. Good value with low value and low temperature dependency. Further, the tilt angle measured by applying a DC electric field at 20 ° C. was as large as 20 °.
(Comparative Example 1)
Ferroelectric liquid crystal compositions (FLC-1), (III-A), (III-B) and Irgacure in the same manner as in Examples except that the monomer composition does not contain the compound represented by formula (I) 651 was mixed at the following ratio to prepare a comparative polymer-stabilized ferroelectric liquid crystal composition (MFLC-C1).

実施例１と同様にして高分子安定化強誘電性液晶組成物中のアクリレート化合物を重合させて液晶表示素子を作製し、Ｖｒ５０を測定すると、４０℃で６Ｖ，２０℃で５Ｖ，０℃で４Ｖと、実施例１よりも電圧が高く、かつ、温度依存が大きく好ましくなかった。また、２０℃で直流電界を印加して測定したチルト角は１５°と実施例よりも小さくなり好ましくなかった。

In the same manner as in Example 1, the acrylate compound in the polymer-stabilized ferroelectric liquid crystal composition was polymerized to produce a liquid crystal display device, and when Vr50 was measured, it was 6 V at 40 ° C., 5 V at 20 ° C., 0 ° C. The voltage was 4 V, which was higher than that of Example 1, and the temperature dependence was not preferable. Further, the tilt angle measured by applying a DC electric field at 20 ° C. was 15 °, which was smaller than that of the example, which was not preferable.

Claims (7)

Formula (Ia)

(In the formula (Ia), A ¹ represents a hydrogen atom or a methyl group,
A ² represents a single bond or an alkylene group having 1 to 15 carbon atoms (one or two or more methylene groups present in the alkylene group are each independently an oxygen atom on the assumption that oxygen atoms are not directly bonded to each other). , —CO—, —COO— or —OCO— may be substituted, and one or two or more hydrogen atoms present in the alkylene group are each independently substituted with a fluorine atom, a methyl group or an ethyl group May be)
A ³ and A ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 18 carbon atoms (one or two or more methylene groups present in the alkyl group are such that oxygen atoms are not directly bonded to each other) Each independently may be substituted with an oxygen atom, -CO-, -COO- or -OCO-, and one or more hydrogen atoms present in the alkyl group are each independently a halogen atom or carbon. Which may be substituted with an alkyl group of 1 to 17 atoms).
A ⁴ and A ⁷ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (one or two or more methylene groups present in the alkyl group are such that oxygen atoms are not directly bonded to each other). Each independently substituted with an oxygen atom, -CO-, -COO- or -OCO-, and one or more hydrogen atoms present in the alkyl group are each independently a halogen atom or a carbon atom. Which may be substituted with an alkyl group of the formula 1 to 9),
k represents 1 to 40;
B ¹ , B ² and B ³ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms (one or two or more methylene groups present in the alkyl group are The oxygen atoms may be independently substituted with oxygen atoms, —CO—, —COO—, or —OCO— as those in which oxygen atoms are not directly bonded to each other), or the general formula (Ib)

(In formula (Ib), A ⁹ represents a hydrogen atom or a methyl group,
A ⁸ is a single bond or an alkylene group having 1 to 15 carbon atoms (one or two or more methylene groups present in the alkylene group are each independently an oxygen atom, assuming that oxygen atoms are not directly bonded to each other). , —CO—, —COO— or —OCO— may be substituted, and one or two or more hydrogen atoms present in the alkylene group are each independently substituted with a fluorine atom, a methyl group or an ethyl group Represents a group represented by: However, the number of the groups represented by the general formula (Ib) among B ¹ , B ^2, and B ³ that are 2k + 1 is 0 to 3. )
A polymerizable compound (I) having a glass transition temperature of −100 ° C. to 25 ° C. of the polymerized polymer of the polymerizable compound, and a general formula (II)

(In the formula, R ¹¹ and R ¹² each independently represent a linear or branched alkyl group having 1 to 18 carbon atoms or a fluorine atom, but R ¹¹ and R ¹² are not simultaneously a fluorine atom. Furthermore, one or two non-adjacent —CH ₂ — groups are —O—, —S—, —CO—, —CO—O—, —O—CO—, —CO—S—, —S. —CO—, —O—CO—O—, —CH═CH—, —C≡C—, a cyclopropylene group or —Si (CH ₃ ) ₂ — may be substituted, and one of the alkyl groups or More hydrogen atoms may be replaced by fluorine atoms or CN groups,
X ^{11 to} X ¹⁷ each independently represents a hydrogen atom, a fluorine atom, a CF ₃ group or an OCF ₃ group,
L ¹¹ , L ¹² , L ¹³ and L ¹⁴ are each independently a single bond, —O—, —S—, —CO—, —CH ₂ O—, —OCH ₂ —, —CF ₂ O—, —OCF _2. —, —CO—O—, —O—CO—, —CO—S—, —S—CO—, —O—CO—O—, —CH ₂ CH ₂ —, —CH═CH— or —C≡. C-
a ¹ , b ¹ , c ¹ and d ¹ each independently represents an integer of 0 or 1, but a ¹ + b ¹ + c ¹ + d ¹ is 1, 2 or 3, and d ¹ when a ¹ is 0 Is 0, and when a ¹ is 1, c ¹ is 0. )
A liquid crystal compound (II) represented by the general formula (III-a)

(In formula (III-a), R ³ and R ⁴ each independently represent a hydrogen atom or a methyl group,
C ⁴ and C ⁵ are each independently 1,4-phenylene group, 1,4-cyclohexylene group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, pyridazine-3,6- Diyl group, 1,3-dioxane-2,5-diyl group, cyclohexene-1,4-diyl group, decahydronaphthalene-2,6-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6 -Diyl group, 2,6-naphthylene group or indane-2,5-diyl group (among these groups 1,4-phenylene group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, The 2,6-naphthylene group and indan-2,5-diyl group are unsubstituted or have one fluorine atom, chlorine atom, methyl group, trifluoromethyl group or trifluoromethoxy group as a substituent. May have two or more.) Represent,
Z ³ and Z ⁵ are each independently a single bond or an alkylene group having 1 to 15 carbon atoms (one or two or more methylene groups present in the alkylene group are such that oxygen atoms are not directly bonded to each other) Each independently may be substituted with an oxygen atom, -CO-, -COO- or -OCO-, and one or more hydrogen atoms present in the alkylene group are each independently a fluorine atom, Which may be substituted with a methyl group or an ethyl group)
Z ⁴ is a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —CH ₂ CH ₂ O—, —OCH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ O—, _{-OCH 2 CH 2 CH 2 -,} - CH 2 CH 2 OCO -, - COOCH 2 CH 2 -, - CH 2 CH 2 COO -, - OCOCH 2 CH 2 -, - CH = CH -, - C≡C- _{, -CF 2 O -, - OCF} 2 -, - COO- or an -OCO-,
n ² represents 0, 1 or 2. However, when n ² represents 2, a plurality of C ⁴ and Z ⁴ may be the same or different. ),
Formula (III-b)

(In formula (III-b), R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group,
C ⁶ is 1,4-phenylene group, 1,4-cyclohexylene group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, pyridazine-3,6-diyl group, 1,3- Dioxane-2,5-diyl group, cyclohexene-1,4-diyl group, decahydronaphthalene-2,6-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, 2,6 A naphthylene group or an indan-2,5-diyl group (among these groups 1,4-phenylene group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, 2,6-naphthylene group and The indane-2,5-diyl group can be unsubstituted or have one or more fluorine, chlorine, methyl, trifluoromethyl or trifluoromethoxy groups as substituents. Represents)
C ⁷ and C ⁸ are each independently benzene-1,2,4-triyl group, benzene-1,3,4-triyl group, benzene-1,3,5-triyl group, cyclohexane-1,2,4. -Represents a triyl group, a cyclohexane-1,3,4-triyl group or a cyclohexane-1,3,5-triyl group, Z ⁶ and Z ⁸ are each independently a single bond or an alkylene group having 1 to 15 carbon atoms. (One or two or more methylene groups present in the alkylene group are each independently substituted with an oxygen atom, —CO—, —COO— or —OCO—, assuming that the oxygen atoms are not directly bonded to each other. And one or two or more hydrogen atoms present in the alkylene group may each independently be substituted with a fluorine atom, a methyl group or an ethyl group).
Z ⁷ and Z ⁹ are each independently a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —CH ₂ CH ₂ O—, —OCH ₂ CH ₂ —, —CH ₂ CH _{2. CH 2 O -, - OCH 2} CH 2 CH 2 -, - CH 2 CH 2 OCO -, - COOCH 2 CH 2 -, - CH 2 CH 2 COO -, - OCOCH 2 CH 2 -, - CH = CH-, _{-C≡C -, - CF 2 O -} , - OCF 2 -, - COO- or an -OCO-,
n ³ represents 0, 1 or 2, but when n ³ represents 2, a plurality of C ⁶ and Z ⁷ may be the same or different, and n ⁵ and n ⁶ are each independently Represents 1, 2 or 3. )
And general formula (III-c)

(In formula (III-c), R ⁷ represents a hydrogen atom or a methyl group,
6-membered rings T ¹ , T ² and T ³ are each independently

(Where m represents an integer of 1 to 4),
n ⁴ represents an integer of 0 or 1,
Y ¹ and Y ² are each independently a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —COO—, —OCO—, —C≡C—, —CH═CH—. , —CF═CF—, — (CH ₂ ) ₄ —, —CH ₂ CH ₂ CH ₂ O—, —OCH ₂ CH ₂ CH ₂ —, —CH ₂ ═CHCH ₂ CH ₂ — or —CH ₂ CH ₂ CH = CH-
Y ³ represents a single bond, —COO—, or —OCO—,
R ⁸ represents a hydrocarbon group having 1 to 18 carbon atoms. And a polymer-stabilized ferroelectric liquid crystal composition comprising at least one polymerizable compound (III) selected from the group consisting of: As a compound of general formula (II), when b ¹ of general formula (II) is 0, at least one of X ^{13 to} X ¹⁶ is a fluorine atom, a CF ₃ group, or an OCF ₃ group, and c ¹ is 0 In this case, at least one of X ¹¹ , X ¹² , X ¹⁵ , X ¹⁶ , and X ¹⁷ is a fluorine atom, a CF ₃ group, or an OCF ₃ group, and when b ¹ = c ¹ = 1, a ¹ = d ^2. The polymer-stabilized ferroelectric liquid crystal according to claim 1, wherein a compound in which ¹ = 0 and at least one of X ^{11 to} X ¹⁷ is a fluorine atom, a CF ₃ group, or an OCF ₃ group is used. Composition. As the compound of the general formula (II), when b ¹ of the general formula (II) is 0, at least one of X ^{13 to} X ¹⁶ is a fluorine atom, and when c ¹ is 0, X ¹¹ , X ¹² , At least one of X ¹⁵ , X ¹⁶ , and X ¹⁷ is a fluorine atom. When b ¹ = c ¹ = 1, a ¹ = d ¹ = 0 and at least one of X ^{11 to} X ¹⁷ is a fluorine atom. 2. The polymer-stabilized ferroelectric liquid crystal composition according to claim 1, wherein a certain compound is used. Formula (IV-a)

(R ⁴¹ represents a linear or branched alkyl group having 1 to 18 carbon atoms, and one or two non-adjacent —CH ₂ — groups in the alkyl group are —O—, —S. -, -CO-, -CO-O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH = CH-, -C≡C-, A cyclopropylene group or —Si (CH ₃ ) ₂ — may be substituted, and one or more hydrogen atoms in the alkyl group may be substituted with a fluorine atom or a CN group, and A ⁴ , B ⁴ and C ⁴ are each independently a 1,4-phenylene group in which one or two hydrogen atoms may be replaced by a fluorine atom, a CF ₃ group, an OCF ₃ group, or a CN group, or a plurality of these groups, One or two hydrogen atoms may be substituted with fluorine atoms, pyrazine-2,5- Diyl group, pyridazine-3,6-diyl group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, one or two hydrogen atoms are replaced by cyano group or methyl group or both Trans-1,4-cyclohexylene group, or 1,3,4-thiadiazole-2,5-diyl group, 1,3-dioxane-2,5-diyl group, 1,3-dithian-2 , 5-diyl group, 1,3-thiazole-2,4-diyl group, 1,3-thiazole-2,5-diyl group, thiophene-2,4-diyl group, thiophene-2,5-diyl group, Represents piperazine-1,4-diyl group, piperazine-2,5-diyl group, naphthalene-2,5-diyl group, and L ⁴¹ and L ⁴² each independently represents a single bond, —O—, —S—, _{-CO -, - CH 2 O -} , - O _{H 2 -, - CF 2 O} -, - OCF 2 -, - CO-O -, - O-CO -, - CO-S -, - S-CO -, - O-CO-O -, - CH 2 CH ₂ —, —CH═CH— or —C≡C— is represented, a ⁴ , b ⁴ , and c ⁴ represent 0 or 1, and the sum of a ⁴ , b ^4, and c ⁴ represents 2 or 3 , X ⁴ represents the general formula (IV-b)

(Wherein R ⁴² represents a single bond or a linear or branched alkylene group having 1 to 18 carbon atoms, and one or two non-adjacent —CH ₂ — groups in the alkylene group are — O-, -S-, -CO-, -CO-O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH = CH-,- C≡C—, a cyclopropylene group, or —Si (CH ₃ ) ₂ — may be substituted, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a CN group. )
Or general formula (IV-c)

(However, R ⁴³ represents a single bond or a linear or branched alkylene group having 1 to 18 carbon atoms, and one or two non-adjacent —CH ₂ — groups in the alkylene group are —O -, -S-, -CO-, -CO-O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH = CH- or -C. R ⁴⁴ , R ⁴⁵ and R ⁴⁶ each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms, and 1 in the alkyl group Two non-adjacent —CH ₂ — groups may be replaced by —O—, —CO—O—, —O—CO—, —CH═CH— or —C≡C—. The polymer-stabilized ferroelectric liquid crystal composition according to claim 1, which contains at least one liquid crystalline compound selected from the group consisting of: General formula (Va)

(Wherein R ⁵¹ represents a linear or branched alkyl group having 1 to 18 carbon atoms, and one or two non-adjacent —CH ₂ — groups in the alkylene group are —O— , —S—, —CO—, —CO—O—, —O—CO—, —CO—S—, —S—CO—, —O—CO—O—, —CH═CH—, —C≡. C—, a cyclopropylene group or —Si (CH ₃ ) ₂ — may be substituted, and one or more hydrogen atoms in the alkylene group may be substituted with a fluorine atom or a CN group, and R ⁵² represents a linear or branched alkyl group having 1 to 18 carbon atoms, and one or two non-adjacent —CH ₂ — groups in the alkyl group are —O—, —S—, -CO-, -CO-O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH = CH-,- C≡C—, a cyclopropylene group, or —Si (CH ₃ ) ₂ — may be substituted, and one or more hydrogen atoms in the alkylene group may be substituted with a fluorine atom or a CN group, A ⁵ , B ⁵ and C ⁵ are each independently one or two hydrogen atoms being a fluorine atom, a CF ₃ group, an OCF ₃ group, a CN group, a CH ₃ group, an OCH ₃ group, or a plurality of these groups 1,4-phenylene group which may be substituted, pyrazine-2,5-diyl group, pyridazine-3,6-diyl group, pyridine-2 in which one or two hydrogen atoms may be substituted with fluorine atoms , 5-diyl group, pyrimidine-2,5-diyl group, trans-1,4-cyclohexylene group in which one or two hydrogen atoms may be replaced by cyano group or methyl group or both, or 1,3,4-thiadiazole-2,5-diyl group, 1,3-dioxane-2,5-diyl group, 1,3-dithian-2,5-diyl group, 1,3-thiazole-2,4 -Diyl group, 1,3-thiazole-2,5-diyl group, thiophene-2,4-diyl group, thiophene-2,5-diyl group, piperazine-1,4-diyl group, piperazine-2,5- A diyl group, naphthalene-2,5-diyl group, a ⁵ , b ⁵ , and c ⁵ each independently represent 0 or 1, * represents an asymmetric carbon, and L ⁵¹ and L ⁵² each independently Single bond, —O—, —S—, —CO—, —CH ₂ O—, —OCH ₂ —, —CF ₂ O—, —OCF ₂ —, —CO—O—, —O—CO—, — CO-S -, - S- CO -, - O-CO-O -, - CH 2 CH 2 -, - CH = CH- or -C Represents C- ^{a, L 53} is represented by the following general formula (V-b) ~ (V -c)

(Wherein d ⁵ , e ⁵ and f ⁵ each independently represents an integer of 0 or more and 6 or less). )
And the general formula (Ve)

(In the formula, R ⁶¹ represents a linear or branched alkyl group having 1 to 18 carbon atoms, provided that one or two non-adjacent —CH ₂ — groups are —O—, —S—. , —CO—, —CO—O—, —O—CO—, —CO—S—, —S—CO—, —O—CO—O—, —CH═CH—, —C≡C—, cyclo A propylene group or —Si (CH ₃ ) ₂ — may be substituted, and one or more hydrogen atoms of the alkyl group may be substituted with a fluorine atom or a CN group, and R ⁶² is a single bond or 1 represents a linear or branched alkylene group having 1 to 18 carbon atoms, provided that one or two non-adjacent —CH ₂ — groups are —O—, —S—, —CO—, —CO. -O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH = CH-, -C≡C -, cyclopropylene group, or -Si (CH ₃₎ 2 _- may be replaced by, may have further one or more of the hydrogen atoms of the alkylene radical are replaced by fluorine atoms or CN groups, R ⁶³ is 1 represents a linear or branched alkyl group having 1 to 18 carbon atoms, provided that one or two non-adjacent —CH ₂ — groups are —O—, —S—, —CO—, —CO. -O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH = CH-, -C≡C-, a cyclopropylene group or -Si (CH ₃ ) It may be replaced with _2- , and one or more hydrogen atoms of the alkylene group may be replaced with a fluorine atom or a CN group, or the following general formula (Vf)

(However, R ⁶⁴ represents a single bond or a linear or branched alkylene group having 1 to 18 carbon atoms, provided that one or two non-adjacent —CH ₂ — groups are —O—, — S-, -CO-, -CO-O-, -O-CO-, -CO-S-, -S-CO-, -O-CO-O-, -CH = CH-, -C≡C- , A cyclopropylene group or —Si (CH ₃ ) ₂ —, and one or more hydrogen atoms of the alkylene group may be replaced with a fluorine atom or a CN group, and R ^65. Can be replaced by hydrogen, a linear or branched alkylene group having 1 to 18 carbon atoms, or fluorine.), And A ⁶ , B ⁶ , and C ⁶ are each independently one or two A hydrogen atom is a fluorine atom, CF ₃ group, OCF ₃ group, CN group, CH ₃ group, or OCH ₃ group, or 1,4-phenylene group which may be replaced by a plurality of these groups, pyrazine-2,5-diyl, pyridazine- in which one or two hydrogen atoms may be replaced by fluorine atoms 3,6-diyl, pyridine-2,5-diyl, pyrimidine-2,5-diyl, trans-1,4- in which one or two hydrogen atoms may be replaced by a cyano group or a methyl group or both Cyclohexylene or 1,3,4-thiadiazole-2,5-diyl, 1,3-dioxane-2,5-diyl, 1,3-dithian-2,5-diyl, 1,3-thiazole- 2,4-diyl, 1,3-thiazole-2,5-diyl, thiophene-2,4-diyl, thiophene-2,5-diyl, piperazine-1,4-diyl, piperazine-2,5-dii , Naphthalene-2,5-diyl, L ⁶¹ and L ⁶² are each independently a single bond, —O—, —S—, —CO—, —CH ₂ O—, —OCH ₂ —, —CF _{2. O -, - OCF 2 -,} - CO-O -, - O-CO -, - CO-S -, - S-CO -, - O-CO-O -, - CH 2 CH 2 -, - CH = CH—, —C≡C—, a ⁶ , b ⁶ , and c ⁶ represent an integer of 0 or 1, and * represents an asymmetric carbon. The polymer-stabilized ferroelectric liquid crystal composition according to claim 1, which contains at least one optically active compound selected from the group consisting of: The content of the polymerizable compound (III) is 0.05% to 7%, and the composition ratio of the polymerizable compound (III) to the polymerizable compound (I) is (III) :( I) = The polymer-stabilized ferroelectric liquid crystal composition according to any one of claims 1 to 5, which is 1: 1 to 49: 1. A liquid crystal display device using the polymer-stabilized ferroelectric liquid crystal composition according to claim 1.