JPH08157397A - Liquid crystal compound, liquid crystal composition containing the same, liquid crystal element containing the same, liquid crystal device using them and displaying method - Google Patents

Abstract

PURPOSE: To obtain a new compound providing a liquid crystal composition useful as a liquid crystal element having excellent switching characteristics, high-speed response, low temperature dependence of optical response rate and a high contrast because of high spontaneous polarization ability. CONSTITUTION: This compound is shown by the formula R1 -A1 -A2 -A3 -A2 (R1 and R2 are each F or CN; A1 is 1,4-cyclohexylene; A2 is 1,4-cyclohexenylene; A3 is thiophene-2,5-diyl or thiazol-2,5-diyl) such as 2-[4-(trans-4-butylcyclohexyl) cyclohex-1-ene]-6-hexylbenzothiazole. The compound, for example, is obtained by reacting a carboxylic acid derivative of the formula R1 -A1 --A2 -COOH with a compound of the formula Z3 -R2 (Z3 is a group to become A3 by reaction with a carboxylic acid derivative and ring formation).

Description

Detailed Description of the Invention

[0001]

The present invention relates to a novel liquid crystalline compound,
The present invention relates to a liquid crystal composition containing the same, a liquid crystal element using the same, and a liquid crystal device, and more specifically, a novel liquid crystal composition having improved response characteristics to an electric field, a liquid crystal display element using the same, a liquid crystal-optical shutter, and the like. And a liquid crystal device using the liquid crystal element for display.

[0002]

2. Description of the Related Art Conventionally, liquid crystals have been applied as electro-optical elements in various fields. Most of the liquid crystal elements currently in practical use are, for example, M. Sch.
adt) and W. Helfri
ch) "Applied Physics Letters"
("Applied Physics Letter
s ") Vol. 18, No. 4 (1971.2.15)
P. 127-128 "Voltage Depend"
ent Optical Activity of a
Twisted Nematic Liquid Cr
TN (Twisted Nem)
atic) type liquid crystal is used.

These are based on the dielectric alignment effect of liquid crystals, and utilize the effect that the average molecular axis direction is directed in a specific direction by an applied electric field due to the dielectric anisotropy of liquid crystal molecules. The optical response speed limit of these devices is said to be milliseconds, which is too slow for many applications.

On the other hand, in the application to a large flat display, the simple matrix drive is the most effective in consideration of price, productivity and the like. The simple matrix method employs an electrode configuration in which a scan electrode group and a signal electrode group are arranged in a matrix, and in order to drive the scan electrode group, an address signal is sequentially and selectively selected and applied to the scan electrode group. Employs a time-division drive system in which a predetermined information signal is synchronized with an address signal and selectively applied in parallel.

However, when the above-mentioned TN type liquid crystal is adopted for the element of such a driving system, the scan electrode is selected and the signal electrode is not selected, or the scan electrode is not selected and the signal electrode is selected. An electric field is applied to a finite amount (so-called "half selection point").

If the difference between the voltage applied to the selection point and the voltage applied to the half selection point is sufficiently large and the voltage threshold value required to align the liquid crystal molecules perpendicularly to the electric field is set to an intermediate voltage value, The display element works normally,
When the number of scanning lines (N) is increased, the time (duty ratio) during which an effective electric field is applied to one selected point while scanning the entire screen (one frame) is reduced by 1 / N. Resulting in.

For this reason, the voltage difference as the effective value applied to the selected point and the non-selected point in the case of repeating scanning is
As the number of scanning lines increases, the number becomes smaller, and as a result, deterioration of image contrast and crosstalk are inevitable drawbacks.

Such a phenomenon is caused by a liquid crystal having no bistability (a stable state in which liquid crystal molecules are aligned horizontally with respect to an electrode surface, and a vertical state only while an electric field is effectively applied). This is an essentially unavoidable problem that occurs when driving (that is, repeatedly scanning) using the temporal accumulation effect.

In order to improve this point, the voltage averaging method, 2
The frequency drive method and the multi-matrix method have already been proposed, but none of them is sufficient, and the increase in the screen size and the density of the display element are stopped because the number of scanning lines cannot be increased sufficiently. This is the current situation.

In order to improve the drawbacks of the conventional liquid crystal device, the use of a liquid crystal device having bistability is explained by Clark and Lagerwell.
11) (Japanese Patent Laid-Open No. 56-10721).
6 gazette, US Pat. No. 4,367,924, etc.). Ferroelectric liquid crystals having a chiral smectic C phase (SmC ^* phase) or H phase (SmH ^* phase) are generally used as the bistable liquid crystal.

This ferroelectric liquid crystal has a bistable state consisting of a first optical stable state and a second optical stable state with respect to an electric field, and therefore the optical modulation used in the above-mentioned TN type liquid crystal. Unlike the element, for example, the liquid crystal is oriented in the first optically stable state with respect to one electric field vector, and the liquid crystal is oriented in the second optically stable state with respect to the other electric field vector. Further, this type of liquid crystal has a property (bistability) of taking one of the two stable states described above in response to an applied electric field and maintaining that state when no electric field is applied.

In addition to the above-mentioned characteristic of having bistability, the ferroelectric liquid crystal has an excellent characteristic of high-speed response. This is because the spontaneous polarization of the ferroelectric liquid crystal and the applied electric field act directly to induce the transition of the alignment state.
It is 3 to 4 orders faster than the response speed due to the effect of the dielectric anisotropy and the electric field.

As described above, the ferroelectric liquid crystal potentially has extremely excellent characteristics, and by utilizing such characteristics, many of the problems of the conventional TN type element described above are solved. A fairly substantial improvement is obtained. In particular, application to high-speed optical optical shutters, high-density, large-screen displays is expected. For this reason, there has been extensive research on ferroelectric liquid crystal materials, but the ferroelectric liquid crystal materials that have been developed to date are sufficient for use in liquid crystal devices, including low-temperature operating characteristics, high-speed response, and contrast. It is hard to say that it has such characteristics.

Between the response time τ, the magnitude Ps of spontaneous polarization and the viscosity η, the following equation [1]

[0015]

[Equation 1] (However, E is the applied electric field.)

Therefore, in order to increase the response speed, there are methods of (a) increasing the magnitude Ps of spontaneous polarization (b) decreasing the viscosity η (c) increasing the applied electric field E.

However, the applied electric field has an upper limit because it is driven by an IC or the like, and it is desirable that the applied electric field be as low as possible. Therefore, it is actually necessary to reduce the viscosity η or increase the value of the spontaneous polarization magnitude Ps.

Generally, in a ferroelectric chiral smectic liquid crystal compound having a large spontaneous polarization, the internal electric field of the cell caused by the spontaneous polarization is also large, and there is a tendency that there are many restrictions on the device structure capable of assuming a bistable state. Further, even if the spontaneous polarization is unnecessarily increased, the viscosity tends to increase accordingly, and as a result, the response speed may not be so fast.

When the operating temperature range of the actual display is, for example, about 5 to 40 ° C., the response speed generally changes about 20 times, which exceeds the limit of adjustment by the drive voltage and frequency. The current situation.

In general, in the case of a liquid crystal element utilizing the birefringence of liquid crystal, the transmittance under the crossed Nicols is expressed by the following formula [2].

[0021]

[Equation 2] In the formula [2], I ₀ is the incident light intensity, I is the transmitted light intensity, θ
_a is the apparent tilt angle defined below, Δn is the refractive index anisotropy, d is the thickness of the liquid crystal layer, and λ is the wavelength of incident light.

The tilt angle θ _a in the above-mentioned non-helical structure
Appears as an angle in the average molecular axis direction of the twisted liquid crystal molecules in the first and second alignment states.
According to the equation [2], the apparent tilt angle θ _a is 22.5.
The maximum transmittance is obtained at an angle of °, and the tilt angle θ _a in the non-helical structure that realizes the bistability needs to be as close as possible to 22.5 °.

However, when it is applied to the ferroelectric liquid crystal having a non-helical structure exhibiting the bistability announced by Clark and Lagerwall, it has the following problems and causes a decrease in contrast. Has become.

First, the apparent tilt angle θ _a in the ferroelectric liquid crystal having a non-helical structure obtained by orienting with a conventional rubbing-treated polyimide film (the angle formed by the molecular axes of two stable states is 1 / 2) is the tilt angle in the ferroelectric liquid crystal (angle θ that is 1/2 the apex angle of the triangular pyramid shown in FIG. 4 described later)
Since it is smaller than that, the transmittance is low.

Secondly, even if the contrast is high in the static state in which no electric field is applied, when driving display is performed by applying a voltage, liquid crystal molecules fluctuate due to a slight electric field during the non-selection period in matrix driving, so that black is produced. It becomes pale.

As described above, in order to put the ferroelectric liquid crystal device into practical use, a liquid crystal composition having a chiral smectic phase having a high-speed response, a small temperature dependence of the response speed, and a high contrast. Is required.

Further, the spontaneous polarization of the liquid crystal composition, the chiral smectic C pitch, the cholesteric pitch, and the temperature at which the liquid crystal phase is taken for uniform switching of the display, good viewing angle characteristics, low temperature storage stability, and reduction of load on the driving IC. It is necessary to optimize the range, optical anisotropy, tilt angle, dielectric anisotropy and the like.

[0028]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a liquid crystal compound effective for allowing the above-mentioned ferroelectric liquid crystal device to be put into practical use, a liquid crystal composition containing the same, and particularly a ferroelectric chiral compound. It is to provide a liquid crystal composition showing a smectic phase, a liquid crystal element using the liquid crystal composition, a liquid crystal device using the same, and a display method.

Another object of the present invention is to provide a liquid crystal element having high operating characteristics and display characteristics and a liquid crystal device using the same, and more specifically, a novel liquid crystal compound having a large spontaneous polarization imparting ability. The present invention provides a liquid crystal element and a liquid crystal device which have excellent switching characteristics, have high-speed response, have low temperature dependence of optical response speed, and have high contrast.

[0030]

The present invention has the following general formula (I):

[0031]

Embedded image R ₁ -A ₁ -A ₂ -A ₃ -R ₂ (I)

[In the formula, R ₁ and R ₂ are F, CN, CF ₃ or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms (one or 2 of the alkyl groups). One or more —CH ₂ — is —O under the condition that heteroatoms are not adjacent.
^{-, - S -, - CO} -, - * CY 1 Y 2 -, - CH = C
It may be replaced with H- and -C≡C-. Also,
One or more —CH ₃ in the alkyl group is C
It may be replaced with H ₂ F, CHF ₂ or CN. Y ₁ and Y ₂ are H, F, CH ₂ F, CHF ₂ and CF
₃ , CN or a linear alkyl group having 1 to 5 carbon atoms is shown. ^* C represents an asymmetric carbon atom. ). A
₁ is 1,4-cyclohexylene, A ₂ is 1,4-cyclohexenylene, A ₃ is thiophene-2,5-diyl, thiazole-2,5-diyl, thiadiazole-2,5-
Diyl, benzoxazole-2,5-diyl, benzoxazole-2,6-diyl, benzothiazole-
2,5-diyl, benzothiazole-2,6-diyl,
It is selected from indane-2,5-diyl and coumarane-2,5-diyl. ]

A liquid crystal compound represented by the formula, a liquid crystal composition containing at least one of the liquid crystal compounds, a liquid crystal element having the liquid crystal composition arranged between a pair of electrode substrates, and the liquid crystal composition. A display method used and a liquid crystal device using the liquid crystal element are provided.

Among the liquid crystalline compounds represented by the above general formula (I), A ₃ is a thiophene-containing compound as a preferable compound from the viewpoints of temperature range of the liquid crystal phase, miscibility, viscosity, orientation and the like.
2,5-diyl, thiazole-2,5-diyl, benzoxazole-2,5-diyl, benzothiazole-
Examples of the liquid crystal compound include 2,6-diyl and indane-2,5-diyl.

Further preferred compounds include liquid crystal compounds in which A ₃ is benzothiazole-2,6-diyl. Further, R ₁ and R ₂ are preferably the following (i) to
Selected from (v).

[0036]

[Chemical 4]

(Where a is an integer from 1 to 16, d and g are integers from 0 to 7, b, e, h and j are integers from 1 to 10,
f represents 0 or 1. However, b + d ≦ 16, e + f
The condition of + g ≦ 16 is satisfied. Z ₁ is a single bond, -O-,-
COO -, - OCO- indicates, _{Z 2} is -COO -, - C
_{H 2 O -, - CH 2} - shows a. )

Next, an example of a method for synthesizing the liquid crystal compound represented by the general formula (I) will be shown.

[0039]

Embedded image

(R ₁ , R ₂ , A ₁ , A ₂ and A ₃ are as defined above. Z ₃ is reacted with a carboxylic acid derivative,
It is a group which is cyclized to A ₃ . )

The specific structural formula of the liquid crystalline compound represented by formula (I) is shown below. The abbreviations used hereinafter in the present invention represent the following groups.

[0042]

[Chemical 6]

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

[0046]

[Table 4]

The liquid crystal composition of the present invention can be obtained by mixing at least one liquid crystal compound represented by the general formula (I) with at least one other liquid crystal compound in an appropriate ratio. The number of other liquid crystal compounds used in combination is 1 to
The range is 50, preferably 1 to 30, and more preferably 3 to 30. The liquid crystal composition according to the present invention is preferably a ferroelectric liquid crystal composition, particularly a ferroelectric chiral smectic liquid crystal composition.

Other liquid crystal compounds used in the present invention are disclosed in JP-A-4-272989 (23) to (39).
Compounds (III) to (XII), preferred compounds (IIIa) to (XIId), and more preferred compounds (IIIaa) to (XIIdb) described on the page are mentioned.

Further, the following general formulas (XIII) to (XXI)
A liquid crystal compound represented by II) can also be used.

[0050]

[Chemical 7]

[0051] A _'4 is PhY' shows a ₉ or Np,
A _'5 is PhY' shows a _9, Cy or Tn.

Ph, Py2, Tn, Tz1, Cy, N
The abbreviations of p, Boa2, Btb2, Ep2, and Gp2 are in accordance with the above definition, and other abbreviations are the following groups.

[0053]

Embedded image

[0054] _{Y '7, Y' 8,} Y '9 represents H or F, respectively. N, Q, and R each represent 0 or 1, and E represents an integer of 2 to 10. X ′ ₇ is a single bond, −
COO -, - OCO -, - CH 2 O- or -OCH
₂ - _{shows, Z '1, Z' 2} , Z '3 are each a single bond, -O -, - COO -, - OCO- shows a.

Here, R ′ ₇ and R ′ ₈ are a hydrogen atom, a fluorine atom, or a linear or branched alkyl group having 1 to 18 carbon atoms, and one or two or more of the alkyl groups. -CH ₂ -is -O unless hetero atoms are adjacent to each other.
-, - CHF -, - CH (CF 3) -, - CO -, - C
H (CN) -, - C (CN) (CH 3) - it may be replaced by.

[0056] Moreover R _'7, R' ₈ is preferably below i)
~ X).

I) a straight-chain alkyl group having 1 to 15 carbon atoms

[0058]

[Chemical 9] p represents an integer of 0 to 5 and q represents an integer of 2 to 11. It may be optically active.

[0059]

[Chemical 10] r is 0 to 6, s is 0 or 1, and t is an integer of 1 to 14. It may be optically active.

[0060]

[Chemical 11] w represents an integer of 1 to 14. It may also be optically active.

[0061]

[Chemical 12] A represents an integer of 0 to 2 and B represents an integer of 1 to 15. It may also be optically active.

[0062]

[Chemical 13] C represents an integer of 0 to 2 and D represents an integer of 1 to 14. It may also be optically active.

Vii) -H viii) -F

[0064]

Embedded image u is an integer of 0, 1 and v is an integer of 1-15. It may also be optically active.

[0065]

[Chemical 15] x represents an integer of 0 to 2 and y represents an integer of 1 to 15. It may also be optically active.

Preferred compounds of the formula (XIII) include (XIIIa) and (XIIIb).

[0067]

Embedded image _{R '7 -Py2-Ph-OCO} -Tn-R' 8 (XIIIa) R '7 -Py2-Ph3F-OCO-Tn-R' 8 (XIIIb)

Preferred compounds of the formula (XVI) are (X
VIa) to (XVIf).

[0069]

Embedded image _{R '7 -Tz1-Ph-O} -R' 8 (XVIa) R '7 -Ph-Tz1-Ph-R' 8 (XVIb) R '7 -Ph-Tz1-Ph-O-R' _{8 (XVIc) R '7 -Ph} -Tz1-Ph-OCO-R' 8 (XVId) R '7 -Ph-Tz1-Ph3F-O-R' 8 (XVIe) R '7 -Ph-Tz1-Ph3F- OCO-R ' ₈ (XVIf)

Preferred compounds of the formula (XVII) include (XVIIa) and (XVIIb).

[0071]

Embedded image _{R '7 -Boa2-Ph-O} -R' 8 (XVIIa) R '7 -Boa2-Np-O-R' 8 (XVIIb)

Preferred compounds of the formula (XVIII) include (XVIIIa) to (XVIIIc).

[0073]

Embedded image _{R '7 -Btb2-Ph-R} ' 8 (XVIIIa) R '7 -Btb2-Ph-O-R' 8 (XVIIIb) R '7 -Btb2-Np-O-R' 8 (XVIIIc)

Preferred compounds of the formula (XIX) are (X
IXa) to (XIXe).

[0075]

Embedded image _{R '7 -Ep2-Ph-R} ' 8 (XIXa) R '7 -Ep2-Ph-O-R' 8 (XIXb) R '7 -Ep2-Ph-OCO-R' 8 (XIXc) _{R '7 -O-Ep2-Ph} -R' 8 (XIXd) R '7 -O-Ep2-Ph-O-R' 8 (XIXe)

Preferred compounds of the formula (XX) are (XX
a) to (XXe).

[0077]

Embedded image _{R '7 -Gp2-Ph-R} ' 8 (XXa) R '7 -Gp2-Ph-O-R' 8 (XXb) R '7 -Gp2-Ph-OCO-R' 8 (XXc) _{R '7 -O-Gp2-Ph} -R' 8 (XXd) R '7 -O-Gp2-Ph-O-R' 8 (XXe)

Preferred compounds of formula (XXI) are (X
XIa) to (XXIg).

[0079]

Embedded image _{R '7 -Py2-Ph- (CH} 2) E -Ph-R' 8 (XXIa) R '7 -Py2-Ph-O- (CH 2) E -Ph-R' 8 (XXIb) _{R '7 -O-Py2-Ph-} (CH 2) E -Ph-R' 8 (XXIc) R '7 -Py2-Ph- (CH 2) E -Cy-R' 8 (XXId) R '7 - _{Py2-Ph-O- (CH 2} ) E -Cy-R '8 (XXIe) R' 7 -O-Py2-Ph- (CH 2) E -Cy-R '8 (xXIf) R' 7 -Py2- _{Ph-O- (CH 2) E} -Tn-R '8 (XXIg)

Preferred compounds of the formula (XXII) include (XXIIa) to (XXIId).

[0081]

Embedded image _{R '7 -Ph- (CH 2)} E -Py2-Ph-R' 8 (XXIIa) R '7 -Ph- (CH 2) E -O-Py2-Ph-R' 8 (XXIIb) _{R '7 -Cy- (CH 2)} E -Py2-Ph-R' 8 (XXIIc) R '7 -Cy- (CH 2) E -O-Py2-Ph-R' 8 (XXIId)

Preferred compounds of the formula (XXIII) include (XXIIIa) and (XXIIIb).

[0083]

Embedded image _{R '7 -Ph-Tz1-Ph-} (CH 2) E -Ph-R' 8 (XXIIIa) R '7 -Ph-Tz1-Ph- (CH 2) E -Cy-R' 8 ( XXIIIa)

When the liquid crystalline compound of the present invention is mixed with one or more kinds of the above liquid crystalline compounds or the liquid crystal composition, the liquid crystalline compound of the present invention occupies in the liquid crystal composition obtained by mixing. The proportion is preferably in the range of 1% by weight to 80% by weight depending on the combination of the compounds to be mixed. In order to put a ferroelectric liquid crystal device into practical use, it is indispensable to satisfy many conditions such as liquid crystallinity in a wide temperature range, high speed response, high contrast and uniform switching. However, it is difficult to satisfy all of them with a single compound, and it is common to prepare a liquid crystal composition using various compounds that are excellent in each aspect. In this respect, the proportion of the liquid crystal compound of the present invention in the liquid crystal composition is preferably 1% by weight to 60% by weight, and further considering that the characteristics of the other liquid crystal compounds constituting the composition are also taken into consideration, 1% by weight to 40% by weight is particularly desirable. If it is less than 1% by weight, the effect of the compound of the present invention is too small, and the characteristics may not be utilized.

When two or more liquid crystal compounds of the present invention are used, the proportion of the mixture of two or more optically active compounds of the present invention in the liquid crystal composition obtained by mixing is 1% by weight to. 80% by weight, preferably 1% by weight in terms of preparing a liquid crystal composition composed of various compounds as described above.
It is particularly desirable that the content is ˜60% by weight, and further 1% by weight to 40% by weight in consideration of taking advantage of the characteristics of the other liquid crystal compounds constituting the composition.

Further, the ferroelectric liquid crystal layer in the ferroelectric liquid crystal device of the present invention comprises a liquid crystal composition containing the liquid crystal compound of the present invention prepared as described above in an isotropic liquid in vacuum. It is preferably obtained by heating to a temperature, enclosing in an element cell, gradually cooling to form a liquid crystal layer, and returning to normal pressure.

FIG. 1 is a schematic cross-sectional view showing an example of a liquid crystal element having a ferroelectric liquid crystal layer of the present invention for explaining the structure of the ferroelectric liquid crystal element.

Referring to FIG. 1, in the liquid crystal element, a liquid crystal layer 1 exhibiting a chiral smectic phase is arranged between a pair of glass substrates 2 provided with a transparent electrode 3 and an insulating orientation control layer 4, respectively, and the layer is formed. The thickness is set by a spacer 5, and a voltage is applied between a pair of transparent electrodes 3 via a lead wire 6 so that a voltage can be applied from a power supply 7. Also, a pair of substrates 2
Are sandwiched between a pair of crossed Nicol polarizing plates 8, and a light source 9 is arranged outside one of them.

The two glass substrates 2 were each provided with In ₂
A transparent electrode 3 made of a thin film of O ₃ , SnO ₂ or ITO (Indium Tin Oxide) is covered. An insulating alignment control layer 4 for arranging the liquid crystal in the rubbing direction is formed by rubbing a polymer thin film such as polyimide with gauze or acetate flocking cloth or the like.

As the insulating material, for example, silicon nitride, silicon nitride containing hydrogen, silicon carbide, silicon carbide containing hydrogen, silicon oxide,
An inorganic material insulating layer such as boron nitride, hydrogen-containing boron nitride, cerium oxide, aluminum oxide, zirconium oxide, titanium oxide or magnesium fluoride is formed, and polyvinyl alcohol, polyimide or polyamide is formed thereon. Align organic insulating materials such as imides, polyester imides, polyparaxylene, polyesters, polycarbonates, polyvinyl acetals, polyvinyl chlorides, polyvinyl acetates, polyamides, polystyrenes, cellulose resins, melamine resins, urea resins, acrylic resins and photoresist resins As the control layer, the insulating orientation control layer 4 may be formed of two layers, or may be an inorganic material insulating orientation control layer or an organic material insulating orientation control layer single layer.

If the insulating orientation control layer is an inorganic type, it can be formed by a vapor deposition method or the like. If it is an organic type, a solution in which an organic insulating substance is dissolved, or a precursor solution thereof (0.1 to 20 in a solvent) is used.
% By weight, preferably 0.2 to 10% by weight) and applied by a spinner coating method, a dip coating method, a screen printing method, a spray coating method, a roll coating method, etc. under predetermined curing conditions (for example, under heating). ) And can be formed by curing.

The layer thickness of the insulating orientation control layer 4 is usually 10Å
1 μm, preferably 10 Å to 3000 Å, more preferably 10 Å to 1000 Å are suitable.

The two glass substrates 2 are held by the spacer 5 at arbitrary intervals. For example, there is a method in which silica beads and alumina beads having a predetermined diameter are sandwiched between two glass substrates as spacers, and the periphery is sealed with a sealing material, for example, an epoxy adhesive material. Other,
A polymer film or glass fiber may be used as the spacer. A ferroelectric liquid crystal, that is, the liquid crystal composition of the present invention as described above is enclosed between the two glass substrates.

The ferroelectric liquid crystal layer 1 in which the ferroelectric liquid crystal is enclosed is generally 0.5 to 20 μm, preferably 1 to 5 μm.
m.

The transparent electrode 3 is connected to an external power source 7 by a lead wire. A polarizing plate 8 is attached to the outside of the glass substrate 2. The example of FIG. 1 is a transmissive type, and includes a light source 9.

FIG. 2 is a schematic drawing of an example of a cell for explaining the operation of the ferroelectric liquid crystal element. 21a and 2
1b is In ₂ O ₃ , SnO ₂ or ITO (indium tin oxide; Indium).
It is a substrate (glass plate) covered with a transparent electrode composed of a thin film such as Tin Oxide), in which liquid crystal of SmC ^* phase or SmH ^* phase in which the liquid crystal molecular layer 22 is oriented perpendicular to the glass surface is enclosed. ing. A thick line 23 represents a liquid crystal molecule, and this liquid crystal molecule 23
Is the dipole moment (P⊥) in the direction orthogonal to the molecule
Has 24. When a voltage of a certain threshold value or more is applied between the electrodes on the substrates 21a and 21b, the helical structure of the liquid crystal molecules 23 is unraveled, and the dipole moment (P⊥) 24 is entirely oriented in the electric field direction. Can be changed. The liquid crystal molecule 23 has an elongated shape and exhibits refractive index anisotropy in the major axis direction and the minor axis direction thereof,
Therefore, it is easily understood that, for example, by disposing crossed Nicols polarizers above and below a glass surface, a liquid crystal optical modulation element whose optical characteristics change depending on the polarity of voltage application is obtained.

The liquid crystal cell preferably used in the liquid crystal element of the present invention has a sufficiently thin thickness (for example, 10 μm).
You can do the following). As shown in FIG. 3, as the liquid crystal layer becomes thinner, the helical structure of the liquid crystal molecules unwinds even when no electric field is applied, and the dipole moment Pa or Pb of the liquid crystal molecule is directed upward (34a) or downward (34b). Take either state. When an electric field Ea or Eb having a polarity equal to or greater than a certain threshold is applied to such a cell by the voltage applying means 31a and 31b, the dipole moment corresponds to the electric field vector of the electric field Ea or Eb. The liquid crystal molecules are turned to the upward stable state 34a or the downward stable direction 34b, and accordingly, the liquid crystal molecules move to the first stable state 3
3a or the second stable state 33b.

As described above, there are two advantages of using such a ferroelectric liquid crystal element as an optical modulation element. The first is that the response speed is extremely fast, and the second is that the orientation of the liquid crystal molecules has bistability. The second point will be further explained with reference to FIG. 3, for example.
When a is applied, the liquid crystal molecules are aligned in the first stable state 33a, but this state is stable even when the electric field is cut off. When a reverse electric field Eb is applied, the liquid crystal molecules are oriented in the second stable state 33b and change their orientation, but they remain in this state even when the electric field is cut off. Further, as long as the applied electric field Ea or Eb does not exceed a certain threshold value, the previous alignment state is still maintained.

FIG. 5 shows an example of drive waveforms used in the present invention. In FIG. 5A, S _S is a selected scan waveform applied to the selected scan line, S _N is a non-selected scan waveform not selected, and I _S is selection information applied to the selected data line. waveform (black), I _N represents the non-selection information signal applied to the data line which is not selected (white). In the figure the _{(I S -S S) (I} N -S S) is the voltage waveforms applied to pixels on a selected scanning line, the voltage _{(I S} -S S) is applied pixel black take the display state, the pixel voltage (I N _{-S S)} is applied takes the display state of white.

FIG. 5B shows the drive waveform shown in FIG.
7 is a time series waveform when the display shown in FIG. 6 is performed. Figure 5
In the driving example shown in FIG. 3, the minimum application time Δt of the single polarity voltage applied to the pixel on the selected scan line is the writing phase t ₂
And the time of 1 line clear t ₁ phase is 2
It is set to Δt.

The values of the parameters V _S , V _I and Δt of the drive waveform shown in FIG. 5 are determined by the switching characteristics of the liquid crystal material used. Here, the bias ratio V _I / (V _I + V _S ) = 1/3 is fixed.

Although it is possible to increase the width of the appropriate driving voltage by increasing the bias ratio, increasing the bias ratio means increasing the amplitude of the information signal, and the flicker in image quality increases. However, the contrast is lowered, which is not preferable. In our study, the bias ratio is 1/3 ~
About 1/4 was practical.

A liquid crystal display device using the liquid crystal device of the present invention in a display panel section and taking a communication synchronizing means by a data format of image information having scanning line address information and a SYNC signal shown in FIGS. To realize.

In the figure, the symbols are as follows. 101 ferroelectric liquid crystal display device 102 graphics controller 103 display panel 104 scanning line driving circuit 105 information line driving circuit 106 decoder 107 scanning signal generating circuit 108 shift register 109 line memory 110 information signal generating circuit 111 driving control circuit 112 GCPU 113 host CPU 114 VRAM

The image information is generated by the graphics controller 102 on the main body side and transferred to the display panel 103 according to the signal transfer means shown in FIGS. 7 and 8. The graphics controller 102 is a CP
U (central processing unit, abbreviated as GCPU 112 hereafter) and VRAM (memory for storing image information) 114 are at the core of management of image information and communication between the host CPU 113 and the liquid crystal display device 101, and control of the present invention. The method is mainly implemented on the graphics controller 102. A light source is arranged on the back surface of the display panel.

[0106]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 2- [4- (trans-4-butylcyclohexyl)
Production of Cyclohex-1-ene] -6-hexylbenzothiazole (Exemplified Compound No. 41) (1) 4- (trans-4-butylcyclohexyl)
Preparation of cyclohex-1-enecarboxylic acid chloride 4- (trans-4-butylcyclohexyl) cyclohex-1-enecarboxylic acid 0.50 g (1.89 m)
M) and 5 ml of thionyl chloride were heated and stirred at 90 ° C. for 1 hour. The excess thionyl chloride was distilled off, and 4- (trans-
0.55 g of a crude product of 4-butylcyclohexyl) cyclohex-1-enecarboxylic acid chloride was obtained.

(2) Preparation of 2- [4- (trans-4-butylcyclohexyl) cyclohex-1-ene] -6-hexylbenzothiazole 5-hexyl-2-aminobenzenethiol zinc salt 0.1.
43 g (0.90 mM) and 0.55 g of 4- (trans-4-butylcyclohexyl) cyclohex-1-enecarboxylic acid chloride were stirred at 200 ° C. for 30 minutes. After the reaction was completed, a dilute aqueous sodium hydroxide solution was added, and the mixture was extracted with chloroform. The extract was washed with water, dried over anhydrous sodium sulfate and dried. After the solvent was distilled off, the residue was purified by silica gel column chromatography (toluene) and recrystallization (toluene / methanol) to give 2- [4- (tran.
0.27 g of s-4-butylcyclohexyl) cyclohex-1-ene] -6-hexylbenzothiazole was obtained. Yield 32%. The phase transition temperature (° C) of this compound is shown below.

[0109]

(Equation 3)

Example 2 The following compounds were mixed in the following parts by weight to prepare a liquid crystal composition A.

[0111]

[Chemical 25]

Further, with respect to this liquid crystal composition A, the following exemplary compounds were mixed in the respective parts by weight shown below to prepare a liquid crystal composition B.

[0113]

[Chemical formula 26]

Example 3 Two 0.7 mm thick glass plates were prepared, an ITO film was formed on each glass plate, and voltage application electrodes were prepared.
Further, SiO ₂ was vapor-deposited on this to form an insulating layer. Silane coupling agent on glass plate [K manufactured by Shin-Etsu Chemical Co., Ltd.
BM-602] 0.2% isopropyl alcohol solution was rotated at a rotation speed of 2000 r.p.m. p. m spinner applied for 15 seconds and surface-treated. After that, heat drying treatment was performed at 120 ° C. for 20 minutes.

A polyimide resin precursor [Toray Industries, Inc. SP-
510] Rotate the 1.5% dimethylacetamide solution at a rotation speed of 2
000r. p. m spinner for 15 seconds. After the film formation, the film was heat-condensed and baked at 300 ° C. for 60 minutes.
At this time, the film thickness of the coating film was about 250Å.

The coating film after firing was rubbed with an acetate flocked cloth, then washed with an isopropyl alcohol solution, and silica beads having an average particle diameter of 2 μm were dispersed on one glass plate, and then each rubbed treatment was performed. The axes were made parallel to each other, and glass plates were laminated using an adhesive sealant [Rixon Bond (Chisso Corporation)] and dried by heating at 100 ° C. for 60 minutes to prepare a cell.

The liquid crystal composition B prepared in Example 2 was poured into this cell in an isotropic liquid state and gradually cooled from the isotropic phase to 25 ° C. at 20 ° C./h to obtain a ferroelectric liquid crystal element. Created. When the cell thickness of this cell was measured with a Berek phase plate, it was about 2 μm.

Using this ferroelectric liquid crystal device, the optical response (transmission light amount change 0 to 90%) under orthogonal Nicols was detected by applying a voltage of peak-to-peak voltage Vpp = 20 V, and the response speed ( Hereinafter, the optical response speed) was measured. The measurement results are shown below.

[0119]

[Table 5] 10 ° C 25 ° C 40 ° C Response speed 492 μsec 253 μsec 141 μsec

Comparative Example 1 A ferroelectric liquid crystal device was prepared in the same manner as in Example 3 except that the liquid crystal composition A mixed in Example 2 was injected into the cell, and the optical response speed was measured. The measurement results are shown below.

[0121]

[Table 6] 10 ° C 25 ° C 40 ° C Response speed 668 μsec 340 μsec 182 μsec

Example 4 Instead of the exemplified compound used in Example 2, the exemplified compounds shown below were mixed in the respective parts by weight shown below to prepare a liquid crystal composition C.

[0123]

[Chemical 27]

A ferroelectric liquid crystal device was prepared in the same manner as in Example 3 except that the liquid crystal composition C was injected into the cell.
The optical response speed was measured and the switching state was observed.
The uniform alignment in this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

[0125]

[Table 7] 10 ° C. 25 ° C. 40 ° C. Response speed 479 μsec 248 μsec 139 μsec

Example 5 The following compounds were mixed in the following parts by weight to prepare a liquid crystal composition D.

[0127]

[Chemical 28]

Further, with respect to this liquid crystal composition D, the following exemplary compounds were mixed in the respective parts by weight shown below to prepare a liquid crystal composition E.

[0129]

[Chemical 29]

A ferroelectric liquid crystal device was prepared in the same manner as in Example 3 except that the liquid crystal composition E was injected into the cell.
The optical response speed was measured and the switching state was observed.
The uniform alignment in this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

[0131]

[Table 8] 10 ° C 25 ° C 40 ° C Response speed 596 μsec 293 μsec 166 μsec

Comparative Example 2 A ferroelectric liquid crystal device was prepared in the same manner as in Example 3 except that the liquid crystal composition D mixed in Example 5 was injected into the cell, and the optical response speed was measured. The results are shown below.

[0133]

[Table 9] 10 ° C 25 ° C 40 ° C Response speed 784 μsec 373 μsec 197 μsec

Example 6 Instead of the exemplified compounds mixed in Example 5, the following compounds were mixed in the respective weight parts shown below to prepare a liquid crystal composition F.

[0135]

Embedded image

A ferroelectric liquid crystal device was prepared in the same manner as in Example 3 except that the liquid crystal composition F was injected into the cell.
The optical response speed was measured and the switching state was observed.
The uniform alignment in this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

[0137]

[Table 10] 10 ° C 25 ° C 40 ° C Response speed 580 μsec 285 μsec 161 μsec

Example 7 The following compounds were mixed in the following parts by weight to prepare a liquid crystal composition G.

[0139]

[Chemical 31]

Further, with respect to this liquid crystal composition G, the following exemplary compounds were mixed in the respective parts by weight shown below to prepare a liquid crystal composition H.

[0141]

Embedded image

A ferroelectric liquid crystal device was prepared in the same manner as in Example 3 except that the liquid crystal composition H was injected into the cell.
The optical response speed was measured and the switching state was observed.
The uniform alignment in this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

[0143]

[Table 11] 10 ° C. 25 ° C. 40 ° C. Response speed 460 μsec 233 μsec 129 μsec

Comparative Example 3 A ferroelectric liquid crystal device was prepared in the same manner as in Example 3 except that the liquid crystal composition G mixed in Example 7 was injected into the cell, and the optical response speed was measured. The measurement results are shown below.

[0145]

[Table 12] 10 ° C. 25 ° C. 40 ° C. Response speed 653 μsec 317 μsec 159 μsec

Example 8 In place of the exemplary compound used in Example 7, the following exemplary compounds were mixed in the respective parts by weight shown below to prepare a liquid crystal composition I.

[0147]

[Chemical 33]

A ferroelectric liquid crystal device was prepared in the same manner as in Example 3 except that the liquid crystal composition I was injected into the cell.
The optical response speed was measured and the switching state was observed.
The uniform alignment in this liquid crystal element was good, and a monodomain state was obtained. The measurement results are shown below.

[0149]

[Table 13] 10 ° C 25 ° C 40 ° C Response speed 438 μsec 220 μsec 120 μsec

As is clear from Examples 3 to 8, the ferroelectric liquid crystal devices containing the liquid crystal compositions B, C, E, F, H and I according to the present invention have operating characteristics at low temperatures and high-speed response. It has been improved and the temperature dependence of the optical response speed has been reduced.

Example 9 Except that the polyimide resin precursor 1.5% dimethylacetamide solution used in Example 3 was replaced with a 2% aqueous solution of polyvinyl alcohol resin [PUA-117 manufactured by Kuraray Co., Ltd.]. Create a ferroelectric liquid crystal element by the method of
The optical response speed was measured in the same manner as in Example 3. The measurement results are shown below.

[0152]

[Table 14] 10 ° C 25 ° C 40 ° C Response speed 490 μsec 252 μsec 140 μsec

Example 10 A ferroelectric liquid crystal device was prepared and carried out in the same manner as in Example 3 except that the alignment control layer was prepared only with a polyimide resin without using SiO ₂ used in Example 3. The optical response speed was measured in the same manner as in Example 3. The measurement results are shown below.

[0154]

[Table 15] 10 ° C 25 ° C 40 ° C Response speed 491 μsec 254 μsec 141 μsec

As is apparent from Examples 9 and 10, even when the element structure was changed, the element containing the ferroelectric liquid crystal composition according to the present invention had much improved low temperature operation characteristics as in Example 3. Moreover, the temperature dependence of the response speed is reduced.

Example 11 Liquid crystal composition J was prepared by mixing the following compounds in the following parts by weight.

[0157]

Embedded image

Further, with respect to the liquid crystal composition J, the exemplified compounds shown below were mixed in the respective parts by weight shown below to prepare a liquid crystal composition K.

[0159]

Embedded image

Next, the optical response was observed using a cell prepared by the following procedure from these liquid crystal compositions. Two 0.7 mm-thick glass plates were prepared, an ITO film was formed on each glass plate, a voltage application electrode was prepared, and SiO ₂ was further vapor-deposited on this to form an insulating layer. Silane coupling agent on glass plate [KBM manufactured by Shin-Etsu Chemical Co., Ltd.
-602] A 0.2% isopropyl alcohol solution was rotated at a rotation speed of 2000 r.p. p. m spinner for 15 seconds,
A surface treatment was applied. After that, heat drying treatment was performed at 120 ° C. for 20 minutes.

Further, a polyimide resin precursor [Toray Industries, Inc. SP-
510] Rotate the 1.0% dimethylacetamide solution at a rotation speed of 3
000r. p. m spinner for 15 seconds. After the film formation, the film was heat-condensed and baked at 300 ° C. for 60 minutes.
The film thickness of the coating film at this time was about 120Å.

The coating film after firing was rubbed with an acetate flocked cloth, washed with an isopropyl alcohol solution, and silica beads having an average particle size of 1.5 μm were dispersed on one glass plate. The rubbing axes were made parallel to each other, the glass plates were laminated using an adhesive sealant [Rixon Bond (Chisso Corporation)], and heated and dried at 100 ° C. for 60 minutes to prepare a cell.

The cell thickness of this cell was measured by a Berek phase plate and found to be about 1.5 μm. The liquid crystal composition K was injected into this cell in an isotropic liquid state, and the
A ferroelectric liquid crystal element was prepared by gradually cooling to 25 ° C at a rate of ° C / h.

When the ferroelectric liquid crystal element was used to measure the contrast at the time of driving at 30 ° C. with the driving waveform (1/3 bias ratio) shown in FIG. 5, the result was 12.0.

Comparative Example 4 A ferroelectric liquid crystal device was prepared in the same manner as in Example 11 except that the liquid crystal composition J mixed in Example 11 was injected into the cell, and the same driving waveform was used at 30 ° C. The contrast at the time of driving was measured. As a result, the contrast was 6.7.

Example 12 A liquid crystal composition L was prepared by mixing the exemplified compounds shown below instead of the exemplified compound used in Example 11 in the respective parts by weight shown below.

[0167]

Embedded image

A ferroelectric liquid crystal device was prepared in the same manner as in Example 11 except that this liquid crystal composition was used, and the contrast at the time of driving at 30 ° C. was measured using the same driving waveform as in Example 11. did. As a result, the contrast is 1
It was 1.8.

Example 13 A liquid crystal composition M was prepared by mixing the exemplified compounds shown below instead of the exemplified compound used in Example 11 in the respective parts by weight shown below.

[0170]

Embedded image

A ferroelectric liquid crystal element was prepared in the same manner as in Example 11 except that this liquid crystal composition was used, and the contrast at the time of driving at 30 ° C. was measured using the same driving waveform as in Example 11. did. As a result, the contrast is 1
It was 3.4.

As is clear from Examples 11 to 13, the ferroelectric liquid crystal devices containing the liquid crystal compositions K, L and M according to the present invention have high contrast during driving.

Example 14 The procedure of Example 11 was repeated except that a 2% aqueous solution of polyvinyl alcohol resin [PUA-117 manufactured by Kuraray Co., Ltd.] was used in place of the 1.0% dimethylacetamide solution of the polyimide resin precursor used in Example 11. A ferroelectric liquid crystal device was produced by the same method as in Example 11, and the contrast at the time of driving at 30 ° C. was measured by the same method as in Example 11, and as a result, the contrast was 14.8.

Example 15 Except that the SiO ₂ used in Example 11 was not used and the alignment control layer was formed only with a polyimide resin, Example 1 was carried out at all.
A ferroelectric liquid crystal device was prepared in the same manner as in Example 1, and
As a result of measuring the contrast at the time of driving at 30 ° C. in the same manner as in 1, the contrast was 15.3.

Example 16 A polyamic acid (LQ1802 manufactured by Hitachi Chemical Co., Ltd.) 1% NMP solution was used in place of the polyimide resin precursor 1.0% dimethylacetamide solution used in Example 11.
A ferroelectric liquid crystal device was prepared in the same manner as in Example 11 except that it was baked at 270 ° C. for 1 hour, and the contrast during driving at 30 ° C. was measured in the same manner as in Example 11. As a result, the contrast was 15.3.

As is clear from Examples 14, 15 and 16, even when the element structure was changed, the element containing the ferroelectric liquid crystal composition according to the present invention showed high contrast as in Example 11. There is. Further, as a result of detailed examination even when the drive waveform was changed, it was found that a liquid crystal element containing the ferroelectric liquid crystal composition of the present invention similarly provided higher contrast.

[0177]

The liquid crystal composition containing the liquid crystalline compound of the present invention can be operated by utilizing the ferroelectricity of the liquid crystal composition. The ferroelectric liquid crystal element of the present invention that can be used in this manner is a liquid crystal element having excellent switching characteristics, high-speed response, temperature dependence of optical response speed, and high contrast. be able to.

A liquid crystal device in which the liquid crystal device of the present invention is used as a display device in combination with a light source, a drive circuit, etc. is a good device.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an example of a liquid crystal element using a liquid crystal exhibiting a chiral smectic phase.

FIG. 2 is a perspective view schematically showing an example of an element cell for explaining the operation of a liquid crystal element utilizing the ferroelectricity of liquid crystal.

FIG. 3 is a perspective view schematically showing an example of an element cell for explaining the operation of a liquid crystal element utilizing the ferroelectricity of liquid crystal.

FIG. 4 is an explanatory diagram showing a tilt angle (θ).

FIG. 5 is a waveform diagram of a driving method of a liquid crystal element used in the present invention.

6 is a schematic diagram of a display pattern when actual driving is performed with the time-series driving waveform shown in FIG. 5 (B).

FIG. 7 is a block configuration diagram showing a liquid crystal display device having a liquid crystal element utilizing ferroelectricity and a graphics controller.

FIG. 8 is a timing chart of image information communication between the liquid crystal display device and the graphics controller.

[Explanation of symbols]

1 Liquid Crystal Layer Having Chiral Smectic Phase 2 Glass Substrate 3 Transparent Electrode 4 Insulating Alignment Control Layer 5 Spacer 6 Lead Wire 7 Power Supply 8 Polarizing Plate 9 Light Source I ₀ Incident Light I Transmitted Light 21a Substrate 21b Substrate 22 Liquid Crystal Having Chiral Smectic Phase Layer 23 Liquid crystal molecule 24 Dipole moment (P⊥) 31a Voltage applying means 31b Voltage applying means 33a First stable state 33b Second stable state 34a Upward dipole moment 34b Downward dipole moment Ea Upward electric field Eb Downward Electric field 101 ferroelectric liquid crystal display device 102 graphics controller 103 display panel 104 scanning line driving circuit 105 information line driving circuit 106 decoder 107 scanning signal generating circuit 108 shift register 109 line memory 110 information signal generating circuit 111 Drive control circuit 112 GCPU 113 Host CPU 114 VRAM

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C07C 43/174 43/20 C 7419-4H 43/225 C 7419-4H 49/21 49/23 255 / 49 323/10 C07D 263/56 277/22 277/24 277/64 285/12 333/08 333/16 417/04 307 C09K 19/34 9279-4H G02F 1/13 500 1/141 (72) Invention Goji Kano Kano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yoko Kosaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (17)

[Claims] 1. A liquid crystal compound represented by the following general formula (I). Embedded image R ₁ -A ₁ -A ₂ -A ₃ -R ₂ (I) [wherein R ₁ and R ₂ are F, CN, CF ₃ or a straight chain having 1 to 20 carbon atoms] A branched or cyclic alkyl group (one or more -CH in the alkyl group
_2- is -O-, -S-, under the condition that hetero atoms are not adjacent to each other.
^{_{-CO -, - * CY 1 Y}} 2 -, - CH = CH -, - C≡
It may be replaced with C-. In addition, one or two or more —CH ₃ in the alkyl group is CH ₂ F or CH.
It may be replaced with F ₂ or CN. Y ₁ ,
Y ₂ represents H, F, CH ₂ F, CHF ₂ , CF ₃ , CN or a linear alkyl group having 1 to 5 carbon atoms.
^* C represents an asymmetric carbon atom. ). A ₁ is 1,4-
Cyclohexylene, A ₂ is 1,4-cyclohexenylene, A ₃ is thiophene-2,5-diyl, thiazole-
2,5-diyl, thiadiazole-2,5-diyl, benzoxazole-2,5-diyl, benzoxazole-2,6-diyl, benzothiazole-2,5-diyl, benzothiazole-2,6-diyl, Indan-
It is selected from 2,5-diyl and coumarane-2,5-diyl. ] Wherein _{A 3} is thiophene-2,5-diyl of the liquid crystal compound represented by formula (I), thiazole-2,5-diyl, benzoxazole-2,5-diyl, benzothiazole -2 , 6-jile, indane-
The liquid crystal compound according to claim 1, which is selected from 2,5-diyl. 3. The liquid crystal compound according to claim 1, wherein A ₃ of the liquid crystal compound represented by the general formula (I) is benzothiazole-2,6-diyl. 4. The liquid crystal compound represented by the general formula (I), wherein R ₁ and R ₂ are any of the following (i) to (v): Liquid crystalline compounds. Embedded image (In the formula, a is an integer of 1 to 16, d and g are integers of 0 to 7, b, e, h and j are integers of 1 to 10, and f is 0 or 1. However, b + d ≦ 16, The condition of e + f + g ≦ 16 is satisfied: Z ₁ is a single bond, —O—, —COO—, or −.
Indicates OCO-, Z ₂ is -COO-, -CH ₂ O-,-.
CH ₂ - shows the. ) 5. A liquid crystal composition comprising at least one of the liquid crystal compounds according to any one of claims 1 to 4. 6. The liquid crystal composition according to claim 5, which contains the liquid crystal compound represented by the general formula (I) in an amount of 1 to 80% by weight. 7. The liquid crystal composition according to claim 5, which contains the liquid crystal compound represented by the general formula (I) in an amount of 1 to 60% by weight. 8. The liquid crystal composition according to claim 5, containing 1 to 40% by weight of the liquid crystal compound represented by the general formula (I). 9. The liquid crystal composition according to claim 5, wherein the liquid crystal composition has a chiral smectic phase. 10. A liquid crystal device comprising the liquid crystal composition according to claim 5 disposed between a pair of electrode substrates. 11. The liquid crystal device according to claim 10, further comprising an alignment control layer provided on the electrode substrate. 12. The liquid crystal device according to claim 11, wherein the alignment control layer is a layer subjected to a rubbing treatment. 13. The liquid crystal device according to claim 10, wherein the pair of electrode substrates are arranged with a film thickness in which the spiral of liquid crystal molecules is released. 14. A display method using the liquid crystal composition according to any one of claims 5 to 9. 15. A liquid crystal device comprising the liquid crystal element according to claim 10. 16. A liquid crystal element drive circuit is provided.
5. The liquid crystal device according to item 5. 17. The liquid crystal device according to claim 15, further comprising a light source.