JPH09302345A - Antiferroelectric liquid crystal composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antiferroelectric liquid crystal composition suppressing drop of tilt angle, manifesting low threshold value, excellent in high speed response, suitable for simple matrix type liquid crystal display device, etc., by respectively compounding specific liquid crystal compounds and a specific optically active compound. SOLUTION: The composition comprising a liquid crystal compound of formula I (R<1> is a linear chain alkyl; X<1> , X<2> are each H, F; (m) is 2 to 8; (n) is 1 to 5; C* is an asymmetric carbon) manifesting a wide range of antiferroelectric properties in the series of its liquid crystal phase, preferably, 5 to 40mol.% (in the composition) of a liquid crystal compound of formula I having a smaller (m) than the above compound of formula I and 10 to 50mol.% of an optically active compound of formula II (R<2> is R<1> ; Y<1> and Y<2> are each H, F; Z<1> and Z<2> are each H, F; (p) is 4 to 8). The preferable transferring threshold voltage value of this composition transferring from antiferroelectric state to ferroelectric state is <=10V/μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antiferroelectric liquid crystal composition suitable for use in a simple matrix type liquid crystal display device.

[0002]

2. Description of the Related Art Liquid crystal display devices have been used for various small display devices to date because of their low voltage operability, low power consumption, and thin display capability. However, with the recent information, the application of liquid crystal display elements to the OA related equipment field, or the television field, and the expansion of applications, the CR
The demand for a high-performance large-sized liquid crystal display device having a display capacity and display quality higher than that of a T display device has been rapidly increasing.

However, as long as the current nematic liquid crystal is used, even an active matrix drive liquid crystal display element used for a liquid crystal television has a large size and a low cost due to the complexity of the manufacturing process and low yield. Is not easy. Even with a simple matrix driven STN type liquid crystal display element, large capacity driving is not always easy, and the response time is limited, making it difficult to display moving images. Further, a narrow viewing angle of a display element using a nematic liquid crystal has become a serious problem.
Therefore, the nematic liquid crystal display element cannot satisfy the demand for the above-mentioned high performance large liquid crystal display element.

In such a situation, a liquid crystal display element using a ferroelectric liquid crystal has attracted attention as a high-speed liquid crystal display element. The surface-stabilized ferroelectric liquid crystal (SSFLC) device, announced by Clark and Lagavar, is noted for its unprecedented fast response speed and wide viewing angle, and its switching characteristics are detailed. In order to optimize various physical constants, many ferroelectric liquid crystals have been synthesized. However, the threshold characteristics are inadequate, the layer structure has a chevron structure, and the contrast is poor. High-speed response is not realized. Alignment control is difficult, which is one of the most important features of SSFLC.
However, there are problems such as difficulty in realizing bistability, which is difficult, and difficulty in recovering the orientation due to mechanical shock, and it is necessary to overcome these problems for practical use.

[0005] Apart from this, the development of elements having a switching mechanism different from that of SSFLC is also proceeding at the same time. Switching between the three stable states of a liquid crystal material having an antiferroelectric phase (hereinafter referred to as an antiferroelectric liquid crystal material) is one of these new switching mechanisms (Japanese Journal of A).
pplied Physics, Vol.27, pp.L729, 1988). The antiferroelectric liquid crystal device has three stable states. That is, the two uniform states (Ur,
Ul) and the third state. Chandani et al. Report that this third state is an antiferroelectric phase (Japanese Journa
l of Applied Physics, Vol.28, pp.L1261, 1989, Japa
nese Journal of Applied Physics, Vol.28, pp.L1265,
1989). Such switching between the three stable states is the first feature of the antiferroelectric liquid crystal device.

A second feature of the antiferroelectric liquid crystal element is that a clear threshold value exists for an applied voltage. Furthermore, it has a memory property, which is the third feature of the antiferroelectric liquid crystal element. By utilizing these excellent characteristics, it is possible to realize a liquid crystal display device having a high response speed and a good contrast.

Another major feature is that the layer structure is easily switched by an electric field.
(Japanese Journal of Applied Physics, Vol.28, pp.L
119,1989, Japanese Journal of Applied Physics, Vo
l.29, pp.L111, 1990). This makes it possible to manufacture a liquid crystal display element having a very small number of defects and a self-healing ability for alignment, and to realize a liquid crystal element having excellent contrast. Furthermore, it has been demonstrated that voltage gradation that is almost impossible with ferroelectric liquid crystal is possible with antiferroelectric liquid crystal, opening the way to full color, and the importance of antiferroelectric liquid crystal is further increasing. (Proceedings of the 4th International Conference on Ferroelectric Liquid Crystals, p. 77, 1993).

As described above, the superiority of the antiferroelectric liquid crystal is becoming clear, but the response temperature for expanding the driving temperature range and realizing a high-definition device is further improved, and the driving speed is improved.
It is desired to improve anti-ferroelectric liquid crystal having a smectic A phase for improving the reduction of driving voltage for reducing the load on the IC and for realizing good alignment.
Of the above, improving the response speed is the most important issue. The demands on the display quality of liquid crystal displays have become stricter year by year, and in particular, the realization of high-definition displays with a large number of scanning lines has become indispensable. In order to realize a display with a large number of scanning lines, it is necessary to increase the response speed.

In the case of antiferroelectric liquid crystals, there are two switchings from the antiferroelectric state to the ferroelectric state and from the ferroelectric state to the antiferroelectric state. Two switching speeds by the voltage, that is, a response speed is an important factor that determines the display quality of the display element. The response speed from the antiferroelectric state to the ferroelectric state (hereinafter referred to as the response speed I) is the writing speed per scan line in simple matrix drive for line-sequential scanning, so one screen is configured. This is the most important because it determines the number of scan lines to be scanned. Response speed I
The faster the number, the more the number of scanning lines can be increased, and a high-definition element can be realized.

Further, the response speed from the ferroelectric state to the antiferroelectric state (hereinafter referred to as response speed II) changes depending on the design of the driving method of the element. For example, it changes depending on the set voltage of the offset voltage. However, if the response speed II is too fast, the ferroelectric state cannot be maintained (maintaining the bright or dark state). Conversely, if the response speed II is too slow, the ferroelectric state changes to the antiferroelectric state (bright or dark). Is not rewritten from the dark state to the dark or bright state), which is inconvenient. The response speed II is set to an optimum value after the drive method is determined. As described above, it is extremely important that the response speed I be high in order to realize a high definition element.

[0011]

In order to use the antiferroelectric liquid crystal as a practical material, in particular, the tilt angle of a certain value or more is maintained, the response speed, the driving voltage, and the temperature range of the antiferroelectric phase. Need to be improved. In addition to these requirements, it is desirable that the smectic A phase be present in terms of orientation. According to M. Nakagawa, the response speed has been shown to depend on the rotational viscosity of liquid crystal molecules in the case of antiferroelectric liquid crystals (Masahiro Nakagawa, Japanese Journal
of Applied Physics, 30, 1759 (1991)). That is, the lower the viscosity, the faster the response speed. Therefore, one method of improving the response speed is to reduce the viscosity of the liquid crystal.

Another method for improving the response speed is to increase the voltage applied to the liquid crystal as much as possible. Normally, the applied voltage must be considered to be constant, so
The substantial voltage (effective voltage) applied to the liquid crystal increases as the threshold voltage decreases. That is, the magnitude of the threshold voltage directly influences the magnitude of the effective voltage applied to the liquid crystal, and if the applied voltage applied to the liquid crystal is considered to be constant, the smaller the threshold voltage is, the more substantial voltage ( Since the effective voltage) becomes large, high-speed response can be expected. Further, as a matter of course, the liquid crystal having a small threshold voltage can reduce the applied voltage, which is convenient because the load on the driving IC can be reduced.

Generally, when an antiferroelectric liquid crystal device as a display is considered, the temperature of the device is considered to be at least about 40 ° C. due to the backlight. Therefore, in order to drive the device normally, the upper limit of the antiferroelectric phase is required. The temperature must be at least 40 ° C or higher, preferably 50 ° C or higher. It is particularly desirable that the smectic A phase is present on the higher temperature side than this temperature in order to obtain good orientation. On the low-temperature side, it is necessary that the element can be driven at least at 10 ° C. Therefore, the lower limit temperature of the antiferroelectric phase is preferably 0 ° C. or lower for normal driving of the device.

The present invention has been made from such a viewpoint, has a large tilt angle, and has a smectic A phase.
An object of the present invention is to obtain an antiferroelectric liquid crystal composition which can secure an antiferroelectric phase in a wide temperature range, has a low threshold voltage, and responds at high speed.

[0015]

That is, the present invention provides a liquid crystal compound represented by the following general formula (1), which has a wide antiferroelectric phase in the liquid crystal phase series: ,
A liquid crystal compound represented by the following general formula (1), wherein the liquid crystal compound (1 ') having a smaller (m) than the liquid crystal compound (1) and an optically active compound represented by the following general formula (2) are mixed. The antiferroelectric liquid crystal composition obtained by

[0016]

Embedded image (Wherein R ¹ and R ² are linear alkyl groups, X ¹ and X ² are hydrogen atoms or one is a fluorine atom and the other is a hydrogen atom, Y ¹ and Y ² are hydrogen atoms or one is a fluorine atom and the other is Hydrogen atom, Z ¹ , Z ²
Is a hydrogen atom or one is a fluorine atom and the other is a hydrogen atom,
m is an integer of 2-8, n is an integer of 1-5, p is an integer of 4-8, and C * is an asymmetric carbon).

The compound represented by the above general formula (1) of the present invention has a terminal long-chain alkyl group (R ¹ ), the presence or absence of fluorine substitution in the phenyl group near the asymmetric carbon side of the core part, m, n It has been confirmed by various studies by the present inventors that the liquid crystal phase series becomes different due to the existence of antiferroelectric phase, ferrielectric phase, and ferroelectric phase.

The liquid crystal compound having an antiferroelectric phase of the general formula (1) used in the present invention has R ¹ having 8 to 10 carbon atoms,
An antiferroelectric liquid crystal in which m is 5, X ¹ is an F atom and n is 2 is preferable. The liquid crystal compound (1 ') has 8 to ¹ carbon atoms in R ^1.
It is preferable that 0, m is 3 or 4, and n is 2, and a liquid crystal compound having a ferrielectric phase in its liquid crystal phase series is preferable. Further, the addition amount thereof is in the range of 1 to 50 mol% of the composition, preferably in the range of 5 to 40 mol%. Further, as the optically active compound of the general formula (2), R ² has 8 to 8 carbon atoms.
It is preferable that 12 and p are 6. Further, the addition amount thereof is in the range of 1 to 60 mol% of the composition, preferably in the range of 10 to 50 mol%.

The liquid crystal compound having the antiferroelectric phase of the general formula (1) or the antiferroelectric liquid crystal having no smectic A phase is usually used in the present invention. Therefore, the orientation is poor and it is difficult to use it alone. From this point, the antiferroelectric liquid crystal composition prepared in the present invention preferably has a smectic A phase on the higher temperature side than the antiferroelectric phase. Further, from the practical temperature range of the liquid crystal display element, at least 0 to
The antiferroelectric phase is preferably in the range of 40 ° C, more preferably in the range of at least 0 to 50 ° C. The threshold voltage when the composition transitions from the antiferroelectric state to the ferroelectric state is preferably 10 V / μm or less, particularly 5 V / μm or less, in view of driving voltage and response speed of the liquid crystal element. Preferably there is.

In the present invention, a simple matrix liquid crystal display device characterized in that the antiferroelectric liquid crystal composition according to claim 1 is sandwiched between substrates in which scanning electrodes and signal electrodes are arranged on a matrix. And the driving of the element by voltage is performed by switching between one antiferroelectric state and two ferroelectric states.

Next, the liquid crystal compound of the general formula (1) used in the present invention is obtained by the method already disclosed by the present inventors.
3-198155). The outline of the manufacturing method is as follows. (B) AcO-Ph (X) -COOH + SOCl ₂ → AcO-Ph (X) -COCl (b) (b) + R * OH → AcO-Ph (3X) -COO-R * (c) (b) ) + Ph-CH ₂ NH ₂ → HO-Ph (3X) -COO-R * (d) RO-Ph-Ph-COOH + SOCl ₂ → RO-Ph-Ph-COCl (e) (ha) + (d) ) → Target liquid crystal compound Ph in the formula is a 1,4-phenylene group, Ph (X) is a fluorine-substituted (X ¹ o
rX ² ), optionally 1,4-phenylene group, R * is of the formula: -C * H
The residue of the optically active alcohol represented by (CF ₃ )-(CH ₂ ) _m OC _n H _{2n + 1} is shown.

The above manufacturing method will be briefly described as follows. (A) is chlorination of p-acetoxybenzoic acid with thionyl chloride. (B) is an ester produced by the reaction of chloride (B) with an optically active alcohol. (C) is deacetylation of ester (B) with benzylamine. (D) is chlorination of 4'-alkyloxybiphenyl-4-carboxylic acid with thionyl chloride. (E) is the formation of the target liquid crystal compound by the reaction of (c) and (d).

The optically active compound used in the present invention can be easily produced by the method already disclosed by the present inventors (JP-A-6-316810). The outline of the manufacturing method is as follows. (1) HO-Ph (Y) -COOH + R ³ COCl → R ³ COO-Ph (X) -COOH (2) AcO-Ph (Z) -COOH + SOCl ₂ → AcO-Ph (X) -COCl ( 3) (2) + R * OH → AcO-Ph (X) -COOR * (4) (3) + PhCH ₂ NH ₂ → HO-Ph (X) -COOR * (5) (1) + SOCl ₂ → R ³ COO-Ph (X) -COCl (6) (4) + (5) → objective optically active compound Ph in the formula is 1,4-phenylene group, Ph (Y), Ph (Z) are fluorine-substituted ( ^{Y 1 orY 2, Z 1 orZ} 2) and each may be a 1,4-phenylene group,
R * represents an optically active alcohol residue.

The above manufacturing method will be briefly described as follows. (1) is the formation of an ester by the reaction of p-hydroxybenzoic acid with an aliphatic acid chloride. (2) is the formation of acid chloride by thionyl chloride of p-acetoxybenzoic acid. (3) is (2)
Of an ester by the reaction of an acid chloride of a salt with an optically active alcohol. (4) is deacetylation of (3) with benzylamine. (5) is the formation of a chlorinated product from thionyl chloride in (1). (6) is the formation of the target optically active compound by (4) and (5).

[0025]

The antiferroelectric liquid crystal composition of the present invention has a low threshold voltage and exhibits a high-speed response, although the tilt angle is small.

[0026]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Example 1 In an antiferroelectric liquid crystal (1A) represented by the following chemical formula, 10 mol% of a liquid crystal compound (1'A) and 38 mol% of an optically active compound (2A) were used.
At a rate of 1A _: C ₈ H ₁₇ -O-Ph-Ph-COO-Ph (3F) -COO-C * H (CF ₃ ) (CH ₂ ) ₅ OC ₂ H ₅ 1'A: C ₈ H ₁₇ -O-Ph -Ph-COO-Ph (3F) -COO-C * H (CF ₃ ) (CH ₂ ) ₃ OC ₂ H ₅ 2A: C ₉ H ₁₉ -COO-Ph-COO-Ph-COO-C * H (CH ₃ ) C ₆ H _{13 In the} formula, Ph is a 1,4-phenylene group, Ph (3F) is a 1,4-phenylene group substituted with fluorine at the 3-position (X ² ), and C * is an asymmetric carbon.

The results of measuring the physical properties of the obtained composition are shown in Tables 1 and 2 below. The composition had a smectic A phase, the temperature range of the antiferroelectric phase was preferable as a practical material, the threshold voltage was low, and high-speed response was exhibited. The phase was identified by texture observation, conoscopic image observation, and DSC (differential differential scanning calorimeter) measurement.

The optical response of the obtained liquid crystal composition was examined at 30 ° C. The cell was produced by the following procedure. After the glass substrate with the ITO electrode was coated with polyimide, only one of the pair of glass substrates was rubbed. A pair of glass substrates were bonded together via a spacer having a particle diameter of 1.6 μm to form a test cell. The cell thickness was 2 μm. The liquid crystal was heated to a temperature at which the liquid crystal was in an isotropic phase, and the liquid crystal was injected into the test cell by a capillary phenomenon. Then, the liquid crystal was aligned in parallel by slow cooling at a rate of 1 ° C./minute, and further cooled to 30 ° C. to measure the physical properties.

Next, a triangular wave voltage of ± 40 V and 50 mHz was applied to the test cell to drive it, and the change in transmitted light was examined. The threshold voltage I is defined as the voltage at which the transmitted light intensity is 90% when the phase transition from the antiferroelectric phase to the ferroelectric phase takes place, with the minimum transmitted light intensity being 0% and the maximum being 100%. The value voltage was measured.
The response time is defined as the response time, which is the time required for the transmitted light intensity to change by 90% when a pulse voltage with a frequency of 10 Hz and 30 V is applied. The response time II is the phase transition from the ferroelectric phase to the antiferroelectric phase. The obtained results are shown in Tables 1 and 2 below.

Example 2 To the antiferroelectric liquid crystal (1A) used in Example 1, 30 mol% of the following ferrielectric liquid crystal (1'B) and 25% of the optically active compound (2B) were added.
Mixed at a molar percentage. 1'B: C ₈ H ₁₇ -O-Ph-Ph-COO-Ph-COO-C * H (CF ₃ ) (CH ₂ ) ₄ OC ₂ H ₅ 2B: C ₁₀ H ₂₁ -COO-Ph-COO- Ph-COO-C * H ( CH 3) C 6 H 13 in formula C * is an asymmetric carbon. The obtained composition had a smectic A phase, and the temperature range of the antiferroelectric phase was preferable as a practical material.

Example 3 In the following antiferroelectric liquid crystal (1B), 16 mol% of the ferrielectric liquid crystal (1'B) used in Example 2 and 20% of the optically active compound (2B) were used.
Mixed at a molar percentage. 1B: C ₉ H ₁₉ -O-Ph-Ph-COO-Ph (3F) -COO-C * H (CF ₃ ) (CH ₂ ) ₅ OC ₂ H _{5 In the} formula, Ph is a 1,4-phenylene group, Ph (3F) is a 1,4-phenylene group substituted with fluorine at the 3-position (X ² ), and C * is an asymmetric carbon.
The obtained composition had a smectic A phase, and the temperature range of the antiferroelectric phase was preferable as a practical material.

Example 4 In the antiferroelectric liquid crystal (1B) used in Example 3, 10 mol% of the following ferrielectric liquid crystal (1'C) and 20% of the optically active compound (2C) were added.
Mixed at a molar percentage. 1'C: C ₉ H ₁₉ -O-Ph-Ph-COO-Ph (3F) -COO-C * H (CF ₃ ) (CH ₂ ) ₄ OC ₂ H ₅ 2C: C ₉ H ₁₉ -COO-Ph (2F) -COO-Ph-COO-C * H (CH ₃ ) C ₆ H _{13 In the} formula, Ph is a 1,4-phenylene group, and Ph (3F) is fluorine-substituted at the 3-position (X ² ) 1 The 1,4-phenylene group and C * represent an asymmetric carbon.
The temperature range of the antiferroelectric phase of the obtained composition was preferable as a practical material.

Example 5 15 mol% of the ferrielectric liquid crystal (2B) used in Example 2 was added to the antiferroelectric liquid crystal (1B) used in Example 2, and the optical structure represented by the following chemical structure was used. The active compound (3D) was mixed in a proportion of 30 mol%. 2D: C ₉ H ₁₉ -COO-Ph-COO-Ph (3F) -COO-C * H (CH ₃ ) C ₆ H _{13 In the} formula, Ph is 1,4-phenylene group and Ph (3F) is 3-position Fluorine-substituted 1,4-phenylene group in (Z ² ), C * represents an asymmetric carbon.
The temperature range of the antiferroelectric phase of the obtained composition was preferable as a practical material.

The physical properties of the compositions obtained in Examples 2 to 5 were measured in the same manner as in Example 1 and the results are shown in Tables 1 and 2 below. In addition, the results of similarly measuring the physical properties of the components used are also shown. The optically active compound represented by the general formula (2) does not have a liquid crystal phase and has melting points of 2A (27), 2B (47),
It was 2C (-7), 2D (45) (melting point (° C) in parentheses).

[0035]

[Table 1] Phase system Sequence component Molar ratio Example 1 Cr (<-20) SCA * (61) SA (73) I 1A / 1'A / 2A = 52/10 / 38〃 2Cr (<-20) SCA * (63) SC * (67) SA (77) I 1A / 1'B / 2B = 45/30/25 〃 3 Cr (<-20) SCA * (61) SC * (71) SA (76) I 1B / 1'B / 2B = 64/16/20 〃 4 Cr (<-20) SCA * (56) SC * (67) SA (72) I 1B / 1'C / 2C = 70/10/20 〃 5 Cr (<-20) SCA * (58) SC * (60) SA (67) I 1B / 1'B / 2D = 70/10/20 LCD 1A Cr (40) SCA * (77) SC * ( 83) I 1B Cr (<-50) SCA * (77) SC * (83) I LCD 1'A Cr (56) SC * (108) SX (110) I 1'B Cr (57) SCγ * (101 ) SA (111) I 1'C Cr (<-20) SCγ * (89) SX (91) I In the above phase series, () indicates the phase transition temperature (° C) and SCA * is the antiferroelectric phase. , SA is a smectic A phase, SC * is a chiral smectic C phase (ferroelectric phase), SCγ * is a ferrielectric phase, Cr is a crystalline phase, and I is an isotropic phase.

[0036]

[Table 2] Threshold voltage I Response time (μsec) Tilt angle (V / μm) I II ° Example 1 4.8 23 1180 29 〃 2 3.0 23 5950 31 〃 3 4.0 35 2000 35 〃 4 4.9 23 3490 33 〃 5 3.6 28 7550 34 LCD 1A 4.2 55 1300 33 1B 4.5 58 3600 37

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hironori Motoyama 22 Wadai, Tsukuba, Ibaraki Mitsubishi Gas Chemical Co., Ltd.

Claims (15)

[Claims] 1. A liquid crystal compound represented by the following general formula (1), which is a liquid crystal compound (1) having a wide antiferroelectric phase in its liquid crystal phase series. Anti-ferroelectric liquid crystal composition obtained by mixing a liquid crystal compound (1 ′) having a smaller (m) than the liquid crystal compound (1) and an optically active compound represented by the following general formula (2) Stuff. Embedded image (Wherein R ¹ and R ² are linear alkyl groups, X ¹ and X ² are hydrogen atoms or one is a fluorine atom and the other is a hydrogen atom, Y ¹ and Y ² are hydrogen atoms or one is a fluorine atom and the other is Hydrogen atom, Z ¹ , Z ²
Is a hydrogen atom or one is a fluorine atom and the other is a hydrogen atom,
m is an integer of 2-8, n is an integer of 1-5, p is an integer of 4-8, and C * is an asymmetric carbon). 2. The liquid crystal compound (1) in the general formula (1), wherein R ¹ has 8 to 10 carbon atoms and m is 5 to 8;
The antiferroelectric liquid crystal composition according to claim 1, which is selected from antiferroelectric liquid crystals having the widest antiferroelectric phase in the liquid crystal phase series. 3. The antiferroelectric liquid crystal composition according to claim 2, wherein the liquid crystal compound (1) is an antiferroelectric liquid crystal in which m is 5 and n is 2 in the general formula (1). 4. The liquid crystal compound (1 ′) according to the general formula (1), wherein R ¹ has 8 to 10 carbon atoms, m is 2 to 4 and n is 2 to 4; The antiferroelectric liquid crystal composition according to claim 1, which is selected from liquid crystal compounds having a ferrielectric phase in the phase sequence. 5. The content of the liquid crystal compound (1 ′) is 5 to 5% of the composition.
The antiferroelectric liquid crystal composition according to claim 1, which is in the range of 40 mol%. 6. The carbon number of R ² in the general formula (2) is 8 to
The antiferroelectric liquid crystal composition according to claim 1, which is 12. 7. The antiferroelectric liquid crystal composition according to claim 1, wherein p in the general formula (2) is 6. 8. The antiferroelectric liquid crystal composition according to claim 1, wherein the content of the optically active compound represented by the general formula (2) is 10 to 50 mol% of the composition. 9. The antiferroelectric liquid crystal composition according to claim 1, wherein the liquid crystal composition has a smectic A phase on a higher temperature side than the antiferroelectric phase. 10. The antiferroelectric liquid crystal composition according to claim 1, which has an antiferroelectric phase in a temperature range of at least 0 to 40 ° C. 11. The antiferroelectric liquid crystal composition according to claim 1, which has an antiferroelectric phase at least in the range of 0 to 50 ° C. 12. The antiferroelectric liquid crystal composition according to claim 1, wherein the threshold voltage at the time of transition from the antiferroelectric state to the ferroelectric state of the composition is 10 V / μm or less. 13. The antiferroelectric liquid crystal composition according to claim 1, wherein the threshold voltage when the composition transitions from the antiferroelectric state to the ferroelectric state is 5 V / μm or less. 14. A simple matrix liquid crystal display device, characterized in that the antiferroelectric liquid crystal composition according to claim 1 is sandwiched between substrates on which scan electrodes and signal electrodes are arranged on a matrix. 15. The liquid crystal composition according to claim 14, wherein the driving by the voltage of the simple matrix liquid crystal element is switched between one antiferroelectric state and two ferroelectric states.