JPS61292125A - Liquid crystal element - Google Patents

Abstract

PURPOSE:To improve monodomain formability or initial orientation by holding a specific liquid crystal or a comsn. contg. said liquid crystal in place between substrates provided with a uniaxial orientation treatment effect. CONSTITUTION:This liquid crystal element has the cell structure sealed with the liquid crystalline compd. having the optically active group expressed by the formula or the liquid crystal compsn. contg. the liquid crystalline compd. having the optically active group expressed by the formula between a pair of the substrates. The smectic phase of the liquid crystal compd. or compsn. is formed by the phase transition from the phase on the higher temp. side than the smectic phase. The surface of at least one substrate of a pair of the substrates has the effect of preferentially arranging, in one direction, the molecular axis direction in contact with the boundary. The compsn. components which transfer the phases like isotropic phase-cholesteric phase-SmA-chiral smectic phase, isotropic phase-cholesteric phase-chiral smetic phase or isotropic phase- SmA-chiral smectic phase during the temp. decreasing process are used for the liquid crystal compsn.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a liquid crystal element applied to a liquid crystal display element, a liquid crystal-optical shutter array, etc., and more specifically, the present invention relates to a liquid crystal element applied to a liquid crystal display element, a liquid crystal-optical shutter array, etc. This invention relates to a liquid crystal element with improved driving characteristics.

[Conventional technology]

As a conventional liquid crystal element, for example, M-Shut (M,
5chadt) and W. Helfrich (W,
He1frich) Author: ``Applfed Physics Leaders''
Letters” Volume 18, No. 4 (published February 15, 1971).

"Voltage Dependent Optical Activity of a Twisted Nematic φ Liquid Crystal"("V
oltage Dependent 0pticalA
activity of a TwiSted
Twisted nematic shown in “NematicLiquid Crystal”
A device using a nematic liquid crystal is known. This TN liquid crystal has a problem in that crosstalk occurs during time division driving using a matrix electrode structure with high pixel density, so the number of pixels is limited.

Furthermore, a display element is known in which a switching element using a thin film transistor is connected to each pixel, and each pixel is switched. However, the process of forming the thin film transistor on the substrate is extremely complicated, and it is difficult to use a display element with a large area. There are some problems that make it difficult to create.

To improve the drawbacks of conventional liquid crystal devices, the use of bistable liquid crystal devices is proposed by Clark (C'
1ark) and Lagerouel (Lage rwa l)
l) (Japanese Unexamined Patent Publication No. 56-107216
(U.S. Pat. No. 4,367,924, etc.). As a liquid crystal having bistability, a ferroelectric liquid crystal having a chiral smectic C phase (S m 0 lines) or H phase (SmH lines) is generally used.

This liquid crystal has a bistable state consisting of a first optically stable state and a second optically stable state with respect to an electric field. Therefore, unlike the optical modulation element used in the TN type liquid crystal described above, for example, one The liquid crystal is aligned in a first optically stable state with respect to the electric field vector, and the liquid crystal is aligned in a second optically stable state with respect to the other electric field vector. In addition, this type of liquid crystal responds to an applied electric field and very quickly responds to the above-mentioned
It has the property of taking one of two stable states and maintaining that state when no electric field is applied. By utilizing such properties, many of the problems of the conventional TN type device described above can be significantly improved. This point will be explained in more detail below in connection with the present invention. However, in order for this ferroelectric liquid crystal with bistability to exhibit predetermined driving characteristics, the liquid crystal placed between a pair of parallel substrates must be in the above two stable states, regardless of the applied state of the electric field. It is necessary that the molecules be arranged in such a state that conversion between them can occur effectively. For example, Sm
For ferroelectric liquid crystals with C" or SmH" phase,
It is necessary to form a region (monodomain) in which the liquid crystal molecule layer having the SmC* or SmH" phase is perpendicular to the substrate surface, and therefore the liquid crystal molecular axes are arranged almost parallel to the substrate surface. However, in the conventional method, The reality is that in ferroelectric liquid crystal devices having bistability, sufficient characteristics cannot be obtained because the alignment state of the liquid crystal having such a domain structure is not necessarily formed satisfactorily.

For example, according to C1ark et al., in order to provide such an orientation state, there are methods of applying a magnetic field, methods of applying a shear force, and methods of applying parallel ridges at small intervals between substrates.
) have been proposed. However, none of these methods necessarily gave satisfactory results. For example, the method of applying a magnetic field is
There are disadvantages in that it requires large-scale equipment and is incompatible with thin-layer cells with good operating characteristics.Also, the method of applying shear force is incompatible with the method of injecting liquid crystal after creating the cell. There are some difficulties. Furthermore, the method of arranging parallel ridges within a cell cannot provide a stable alignment effect by itself.

[Problems to be Solved by the Invention] In view of the above-mentioned circumstances, the purpose of the present invention is to solve problems that have potential as display elements with high-speed response, high-density pixels, and large area, or optical shutters with high shutter speeds. The object of the present invention is to provide a ferroelectric liquid crystal element that can fully exhibit its characteristics by improving the monodomain formation property or initial orientation, which has been a problem in the past.

[For production]

As a result of research in line with the above-mentioned objective, the present inventors have discovered that a specific liquid crystal or a composition containing the liquid crystal is sandwiched between substrates that have been given a uniaxial alignment treatment effect, and a phase on the higher temperature side than the smectic phase, e.g. Cholesteric phase (chiral nematic phase), nematic phase When a phase transition from an isotropic phase is caused by slow cooling, for example, when forming SmA or a chiral smectic phase, a monodomain in which liquid crystal molecules are aligned in one direction is formed. We have discovered that as a result, we can obtain a liquid crystal device with a structure that allows both operation of the device based on the bistability of the ferroelectric liquid crystal and monodomain properties of the liquid crystal layer.

[Means for solving problems]

The liquid crystal element of the present invention is based on the above-mentioned findings,
More specifically, a liquid crystal composition containing a liquid crystal compound having an optically active group represented by the following general formula (I) between a pair of substrates, or a liquid crystal compound having an optically active group represented by the following general formula (1) The liquid crystal compound or composition has a cell structure in which a substance is encapsulated therein, and a smectic phase of the liquid crystal compound or composition is formed by phase transition from a phase on a higher temperature side than the smectic phase, and the surface of at least one of the pair of substrates is It is characterized in that it has the effect of preferentially arranging the molecular axes that meet at the interface in one direction.

General formula (I) CH3 R-0-CH-CH2- [In general formula (I), R represents a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms . The present invention shows asymmetric carbon atoms] [Examples] The present invention will be described in further detail below with reference to the drawings as necessary.

The liquid crystal used in the present invention has ferroelectricity, and specifically has a chiral smectic C phase (S m C
main), H phase (SmH main), I phase (SmH main), J phase (SmH main),
mJ book), phase (SmK”), phase G (SmG book) or F
A liquid crystal having a phase (SmF phase) can be used.

Specific examples of the liquid crystal compound having an optically active group represented by the general formula (I) are as follows.

In the above formula, R is a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. If the number of carbon atoms is 21 or more -F, the viscosity and molar volume of the final functional material will increase, which is not preferable. Moreover, the preferable number of carbon atoms of R is 4 to 16. Specific examples of R include a linear alkyl group, a branched alkyl group, a cycloalkyl group, a linear alkenyl group, a branched alkenyl group,
Cycloalkenyl group, linear alkabienyl group, branched alkabuenyl group, cycloalkabuenyl group, linear alkatrienyl group, branched alkabienyl group,
There are linear alkynyl groups, branched alkynyl groups, and aralkyl groups. Also, wood exhibits asymmetric carbon atoms.

In addition, azo-, azoxy derivatives, ring-assembled hydrocarbon derivatives into which an optically active group represented by the general formula (I) is introduced,
Condensed polycyclic hydrocarbon derivatives, heterocyclic derivatives, fused heterocyclic derivatives, ring-assembly heterocyclic derivatives, etc. can be used, and specifically, optically active groups represented by the general formula (I) have been introduced. Azobenzene derivatives, azoxybenzene derivatives,
Biphenyl derivatives, terphenyl derivatives, phenylcyclohexane derivatives, benzoic acid derivatives, pyrimidine derivatives, pyrazine derivatives, pyridine derivatives, stilbene derivatives, tolan derivatives, chalcone derivatives, bicyclohexane derivatives, cinnamic acid derivatives, etc. can also be used as liquid crystal compounds. can.

The lactic acid derivatives used in synthesizing these liquid crystal compounds can be synthesized by the following method.

(a) Book (b) Non (C) Ne (d) H3 Book (e) Non (f) RI in the above reaction formula can be selected from a wide range of carbon numbers, and specifically, iodobutane,
iodopentane, iodohetton, iodohebutane,
Linear saturated hydrocarbon iodides such as iodooctane, iodononane, iododecane, iodoundecane, iodododecane, iodotridecane, iodobutrabucan, iodopentadecane, iodoundecane, iodoheptadecane, iodooctadecane, iodononadecane, iodoeicosane, etc. ; Branched saturated hydrocarbon iodides such as 2-iodobutane, l-iodo-2-methylpropane, l-iodo-3-methylbutane; cyclic unsaturated carbonization such as iodobenzine, iodophenacil, 3-ioF-1-cyclohexene, etc. Hydrogen iodide; iodocyclopentane, iodocyclohexane.

There are cyclic saturated hydrocarbon iodides such as 1-iodo-3-methylcyclohexane, iodocyclohebutane, and iodocyclooctane.

From various lactic acid derivatives obtained by such methods, the following general formulas (II) to (IV
) was obtained.

H3 υ -----(II) [However, in the above general formula (II), R represents a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and R1 and R2 represents an alkyl group or an alkoxy group having 1 to 20 carbon atoms. ] [However, in general formula (m), R has 1 carbon atom
-20 linear, branched or cyclic saturated or unsaturated hydrocarbon group, R2 is an alkyl group having 1 to 20 carbon atoms or alkyl group (IV) [However, the above general formula ( TV), R represents a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and R3 represents an alkyl group or alkoxy group having 1 to 20 carbon atoms. ] Representative examples of the liquid crystal compound used in the liquid crystal element of the present invention are as follows.

(1) Hebutyloxypropyl-4'-octyloxybiphenyl-4-carboxylate (2) Butoxypropyl-4'-octyloxybiphenyl-4-carboxylate (3) 4-(5-(4'-butyl) phenyl)pyridine-
2-yl]benzoic acid-21-dodecyloxypropyl ester (4) 4-(5-hebutylpyridin-2-yl)benzoic acid-2'-decyloxypropyl ester (5) α-propyloxypropyl Bill-4'-heptyl-
Terphenylcarboxylate (6) (5-(4'-pentylcyclohexyl)pyrimidin-2-yl)benzoic acid 2'-ethoxypropyl ester (7) α-octadecyloxypropyl-4'-hebutylbiphenyl-4- Carboxylate These liquid crystal compounds can be obtained by the synthesis method described in Japanese Patent Application No. 59-233269.

When these liquid crystal compounds exhibit a chiral smectic phase alone, they can be used alone or in combination of two or more, or they can be used as a mixture with the liquid crystal compounds shown in Table 1 or Table 2 below, or they can be used alone. If the liquid crystal does not exhibit a chiral smectic phase, a chiral smectic phase can be obtained by mixing it with the liquid crystal shown in Table 2 below.
1-Methylbutyl-α-methylcinnamate-COOCR
2CI(C2H5*4.4'-azoxycinnamic acid-bis(2-
Methylbutylbiphenyl-4'-carboxylate Biphenyl-4'-carboxylate 91, 5°C 93°C Crystal ;= SmC* ;i SmA 8,. Book and “SmA 8”°01 Table 2 (A) Cholesteryl propionate (B)
Cholesteryl nonanate (C) Cholesteryl palmitate (D) Cholesteryl nonanate to 4-(2''-methylbutyl)-4'-cyanobiphenyl -54℃ SmA -□ = uz
0°C4-(2″-methylbutyloxy)-4′-cyanobiphenyl4-cyanobenzylidene-4′-(2-methylbutyl)aniline 4-(2-methylbutyl)-4
'-hexyloxyazobenzene crystal; i cholesteric phase; secondary real phase 4-(2-methylbutyl)feco-4'-desyloxybenzoate liquid crystal; i 5
nlA ;i cholesteric phase ;i isoreal phase 4-
Hexyloxy-4'-(2-methylbutyl)benzoate ~ cholesteric phase, /17°C When constructing an element using these materials, the liquid crystal compound
In order to maintain the temperature state such that it becomes the m C'' phase or the S m H'' phase, the element can be supported by a copper block or the like in which a heater is embedded, if necessary.

FIG. 1 schematically depicts an example of a cell for explaining the operation of a ferroelectric liquid crystal. 21a and 21b are In
203.5n02 or ITO
- A substrate (glass plate) coated with a transparent electrode made of a thin film such as Tin Oxide), between which a liquid crystal molecular layer 22 is oriented perpendicularly to the glass surface.
C" phase or SmH" phase liquid crystal is sealed.

A thick line 23 represents a liquid crystal molecule, and this liquid crystal molecule 23 has a dipole moment (on P) 24 in a direction perpendicular to the molecule.

When a voltage higher than a certain threshold is applied between the electrodes on the substrates 21a and 21b, the helical structure of the liquid crystal molecules 23 is unraveled, and the liquid crystal molecules 23 are twisted so that all the dipole moments (P, L) 24 are oriented in the direction of the electric field. The orientation direction can be changed. The liquid crystal molecules 23 have an elongated shape and exhibit refractive index anisotropy in the long axis direction and short axis direction. Therefore, for example, if crossed Nicol polarizers are placed above and below the glass surface,
It is easily understood that this is a liquid crystal optical modulation element whose optical characteristics change depending on the polarity of applied voltage.

The liquid crystal cell preferably used in the liquid crystal element of the present invention can have a sufficiently thin thickness (for example, 10 wells or less). As the liquid crystal layer becomes thinner, as shown in Figure 2, the helical structure of the liquid crystal molecules unwinds even in the absence of an applied electric field and assumes a non-helical structure, with the dipole moment (Pa or Pb) pointing upward. (34a) or downward (34b).

To such a cell, as shown in FIG.
1b, the dipole moment is given by the electric field Ea
Alternatively, the direction changes to upward direction 34a or downward direction 34b in accordance with the electric field vector of Eb, and accordingly, the liquid crystal molecules are oriented to either the first stable state 33a or the second stable state 33b.

As mentioned earlier, there are two advantages to using such ferroelectricity as an optical modulation element.

The first is that the response speed is extremely fast, and the second is that the alignment of liquid crystal molecules has bistability. To further explain the second point, for example with reference to FIG. 2, the electric field Ea
When the voltage is applied, the liquid crystal molecules are aligned in a first stable state 33a, and this state remains stable even when the electric field is turned off. Furthermore, when an electric field Eb in the opposite direction is applied, the liquid crystal molecules are oriented to the twelfth stable state 33b and change their orientation, but they remain in this state even after the electric field is turned off. Further, as long as the applied electric field Ea does not exceed a certain threshold value, each orientation state is maintained. In order to effectively realize such fast response speed and bistability, it is preferable that the cell be as thin as possible.

The biggest problem in forming devices using liquid crystals with such ferroelectricity is, as mentioned earlier, that SmC
It is difficult to form a highly monodomain cell in which a layer having a "phase or SmH" phase is aligned perpendicular to the substrate surface and liquid crystal molecules are aligned approximately parallel to the substrate surface, and this It is the main objective of the present invention to provide a solution to this point.

FIGS. 3A and 3B show an embodiment of a liquid crystal element according to the present invention. FIG. 3(A) is a plan view of the liquid crystal element of the present invention, and FIG. 3(B) is a sectional view taken along the line A-.

The cell structure 100 shown in FIG. 3 includes a pair of substrates 101a made of glass plates, plastic plates, etc. =101
b is held at a predetermined distance by a spacer 104, and has a cell structure bonded with an adhesive 106 to seal the pair of substrates, and furthermore, an electrode consisting of a plurality of transparent electrodes 102 is placed on the substrate lO1. A group (for example, a group of electrodes for applying a scanning voltage in a matrix electrode structure) is formed in a predetermined pattern such as a strip pattern. Board 1
An electrode group (for example, a signal voltage application electrode group in a matrix electrode structure) is formed on the oib, which is made up of a plurality of transparent electrodes 102b intersecting with the transparent electrode 102a described above.

The substrate 101b provided with such a transparent electrode 102b may contain, for example, silicon oxide, silicon dioxide, aluminum oxide, zirconia, magnesium fluoride, cerium oxide, cerium fluoride, silicon nitride, silicon carbide, boron nitride, etc. inorganic insulating materials and polyvinyl alcohol,
Polyimide, polyamideimide, polyesterimide,
The alignment control film 105 may be formed using an organic insulating material such as polyparaxylerin, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyamide, polystyrene, cellulose resin, melamine resin, urea resin, or acrylic resin. can.

The orientation control film 105 is obtained by forming a film of an inorganic insulating material or an organic insulating material as described above, and then rubbing the surface of the film in one direction with velvet, cloth, or paper.

In another preferred embodiment of the present invention, the alignment control film 105 can be obtained by forming a film of an inorganic insulating material such as SiO or 5i02 on the substrate 101b by oblique vapor deposition.

In the apparatus shown in FIG. 5, a Pel jar 501 is placed on an insulating substrate 503 having a suction port 505, and a vacuum pump (not shown) extending from the suction port 505 evacuates the Pel jar 501. . Tungsten or molybdic acid crucible 507 is Pelger 50
Several grams of crystals 508 such as SiO, 5i02°MgF2, etc. are placed in the crucible 507. The crucible 507 has two lower arms 507a.
.

507b, and each of the arms has conductive wires 509 and 510, respectively.
connected to. A power supply 506 and a switch 5θ4 are connected in series between the external conductors 509 and 510 of the Pelger 501. The substrate 502 is placed in the crucible 5 inside the Pelger 501.
07 and at an angle θ with respect to the vertical axis of the Pelger 501.

When the switch 504 is opened, the Pelger 501 is first brought into a vacuum state of about 10-5 mmHg pressure, and then the switch 504 is closed and the power is turned on until the Lupo 507 becomes incandescent at a suitable temperature and the crystal 508 is evaporated. Power is supplied through WRM'i 506. Suitable temperature range (700-1000℃)
The current required for this is approximately 100100a. crystal 5
08 is then evaporated to form an upward molecular flow indicated by S in the figure, and its is incident on the substrate 502 at an angle of θ with respect to the substrate 502, so that the substrate 502 is coated. Ru. The angle θ is the above-mentioned "incident angle", and the direction of the fluid S is the above-mentioned "oblique deposition direction". It is determined by the calibration of the power source 50.
6 and opens switch 504 to cool the Pel jar 501 and its interior. Next, the pressure is increased to atmospheric pressure and the substrate 502 is removed from the Pelger 501.

In another specific example, after forming a film of the above-mentioned inorganic insulating material or organic insulating material on the surface of the substrate toib made of glass or plastic or on the substrate 101b, the surface of the film is etched by an oblique etching method. By doing so, an orientation control effect can be imparted to the surface.

It is preferable that the aforementioned orientation control film 105 also functions as an insulating film at the same time, and for this purpose, this orientation control film 1fI
The film thickness of 105 is generally 100 to 1, preferably 50
It can be set in a range of 0 to 5000 people. This insulating film also has the advantage of being able to prevent the generation of current caused by trace amounts of impurities contained in the liquid crystal layer 103, and therefore does not deteriorate the liquid crystal compound even if the operation is repeated.

Further, in the liquid crystal element of the present invention, a film similar to the above-described alignment control film 105 can be provided on the other substrate 101.

The liquid crystal layer 103 in the cell structure 100 shown in FIG.
SmC)IClSmH*, SmI)k, SmJ*, Sm
K*, SmG)k, SmF)k. This chiral smectic phase liquid crystal layer 103 is formed by gradual cooling (l″C-tO°C/hour) from a phase on the higher temperature side than the smectic phase, such as a cholesteric phase (chiral nematic phase), a nematic phase, or a real phase. During the cooling process, Sm
SmA (smectic A phase) is formed by a phase transition to a chiral smectic phase in the temperature decreasing process by slow cooling, or it is formed by a phase transition from a cholesteric phase etc. to a chiral smectic phase without diaphragming SmA. can be formed by

An important point of the present invention is that a monodomain smectic phase can be formed when the above-mentioned liquid crystal is used in the temperature decreasing process by slow cooling.

The liquid crystal composition used in the present invention is a composition that undergoes a phase transition in the temperature-lowering process to a tokiyoshi phase-cholesteric phase-SmA-chiral smectic phase, a tokiyoshi phase-cholesteric phase-a chiral smectic phase, or a tokiyoshi phase-SmA-chiral smectic phase. It can be done in minutes.

FIG. 4 shows another specific example of the liquid crystal element of the present invention. The liquid crystal element shown in FIG. 4 consists of a pair of substrates 101a and 1
A plurality of spacer members 203 are arranged between 01b. This spacer member 203 is, for example, the alignment control film 10
5iO1Si0 on the substrate 101a provided with 5iO1Si0
2, A text 203, inorganic compounds such as TiO2 or polyvinyl alcohol, polyimide, polyamideimide,
Resins such as polyesterimide, polyparaxylylene, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, polyamide, polystyrene, cellulose resin, melamine resin, Yurya resin, acrylic resin, and photoresist resin are prepared by an appropriate method. After forming a film, a spacer member 203 is placed in a predetermined position.
can be obtained by etching so that

Such a cell structure 100 includes substrates 101a and 101b.
Polarizers 107 and 108 in a crossed Nicol state or a parallel Nicol state are respectively arranged on both sides of the electrodes 102a and 102b, and optical modulation occurs when a voltage is applied between the electrodes 102a and 102b.

Hereinafter, the present invention will be explained according to examples.

[Example 1] A square glass substrate on which a striped ITO film with a pitch of 100 m and a width of 62.5 ILm was provided as an electrode was prepared, and the side on which the ITO film serving as the electrode was provided faced downward. The sample was placed in the oblique evaporation apparatus shown in FIG. 5, and then a 5i02 crystal was placed in a molybdenum crucible.

Thereafter, the inside of the vapor deposition apparatus was made into a vacuum state of about 10-5 Torr, and then 5i02 was peeled and vapor-deposited on the glass substrate by a predetermined method to form an 800 obliquely vapor-deposited film (electrode plate A).

On the other hand, a polyimide forming solution (rPIQJ manufactured by Hitachi Chemical Co., Ltd.; non-volatile content concentration 14.5 wt%) was placed on a glass substrate on which a similar striped ITO film was formed.
was applied using a spinner coater and heated at 120° C. for 30 minutes to form a film of 800 people (electrode plate B).

Next, a thermosetting epoxy adhesive is applied to the periphery of the A electrode plate except for the area that will become the injection port using a screen printing method, and then the striped pattern electrodes of the A electrode plate and the B electrode plate are overlapped so that they are perpendicular to each other. The distance between the two electrode plates was maintained at 2 pm using a polyimide spacer.

The liquid crystal composition A shown below in the Edoyoshi phase was injected into the thus prepared cell through the injection port, and the injection port was sealed.

When this cell was slowly cooled to a temperature maintained at 25°C and a pair of polarizers were placed in a crossed nicol state, microscopic observation revealed that it had a non-helical structure and was a monodomain with no orientation defects. It was found that SmC)k was formed.

'ILAU口E叛J [Example 2] Two square glass substrates on which striped ITO electrodes with a pitch of 1100 JL and a width of 62.5 pm are provided are prepared, and a polyimide forming solution (Example 2) is prepared on each substrate. 1) using a spinner coater to coat 120
℃ for 30 minutes, then 200℃ for 60 minutes and 35 minutes.
Heating was performed at 0° C. for 30 minutes to form an 800-layer polyimide film.

The polyimide films formed on these two substrates were rubbed with velvet so that when they were stacked, the rubbing directions were parallel and the striped ITO electrodes were perpendicular to each other.

Next, the two substrates are stacked so that the rubbing directions are parallel to each other, and a thermosetting epoxy adhesive is applied to the periphery of one substrate by screen printing except for the area that will become the injection port. The two substrates were stacked on top of each other, and the distance between the two substrates was maintained at 2 pm with a polyimide spacer.

The above-mentioned liquid crystal composition A, which was in the isokyoshi phase, was injected into the cell thus prepared through the injection port, and the injection port was sealed. The temperature of this cell was lowered by slow cooling, and while the temperature was maintained, a pair of polarizers were placed in a crossed nicol state, and microscopic observation revealed that it had a non-helical structure and was a monodomain SmC) IC with no orientation defects. [Examples 3 and 4] In place of the liquid crystal composition used when creating the liquid crystal element of Example 2, liquid crystal compositions B (Example 3) and C (Example 4) having the following compositions were used. ) A ferroelectric liquid crystal device was produced in exactly the same manner as in Example 2, except that ferroelectric liquid crystal elements were used.

When observing this ferroelectric liquid crystal element with a polarizing microscope, we found that
A non-helical monodomain with no orientation defects was confirmed.

[Effects of the Invention] As described above, according to the present invention, by using the above-mentioned specific liquid crystal, it is possible to form a smectic phase free from alignment defects, and in particular, by using the above-mentioned specific liquid crystal, it is possible to form a smectic phase free from alignment defects. A defect-free, non-helical ferroelectric liquid crystal phase can be formed.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing a liquid crystal element using chiral smectic liquid crystal. FIG. 2 is a perspective view schematically showing the bistability of the liquid crystal element. FIG. 3(A) is a plan view showing the liquid crystal element of the present invention, and FIG. 3(B) is a cross-sectional view taken along line A-. Fourth
The figure is a sectional view showing another specific example of the liquid crystal element of the present invention. FIG. 5 is a cross-sectional view schematically showing an oblique evaporation apparatus used in producing the liquid crystal element of the present invention.

Claims (1)

[Scope of Claims] (1) A liquid crystal compound having an optically active group represented by the following general formula (I) or a liquid crystal compound having the following general formula (I) between a pair of substrates.
) has a cell structure that encapsulates a liquid crystal composition containing a liquid crystal compound having an optically active group represented by the formula, and forms a smectic phase of the liquid crystal compound or composition by phase transition from a phase on the higher temperature side than the smectic phase. At the same time,
A liquid crystal element characterized in that the surface of at least one of the pair of substrates has the effect of arranging the molecular axes in one direction preferentially in the direction of the molecular axes in contact with each other at an interface. General Formula (I) ▲ Numerical formulas, chemical formulas, tables, etc. are available▼ [In the above general formula, R represents a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. Also, * indicates an asymmetric carbon atom. (2) The liquid crystal element according to claim 1, wherein the liquid crystal compound is a compound represented by the following general formula (1). General formula (1) ▲ Numerical formulas, chemical formulas, tables, etc. are included ▼ [In the formula, R_1 is an alkyl group or an alkoxy group having 1 to 20 carbon atoms. R is a linear, branched or cyclic saturated or unsaturated hydrocarbon having 1 to 20 carbon atoms. * is an asymmetric carbon atom. (3) The liquid crystal element according to claim 1, wherein the liquid crystal compound is a compound represented by the following general formula (2). General formula (2) ▲ Numerical formulas, chemical formulas, tables, etc. are available▼ [In the formula, R_2 is an alkyl group or an alkoxy group having 1 to 20 carbon atoms. R is a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. * is an asymmetric carbon atom. (4) The liquid crystal element according to claim 1, wherein the liquid crystal compound is a compound represented by the following general formula (3). General formula (3) ▲There are numerical formulas, chemical formulas, tables, etc.▼ [In the formula, R_3 is an alkyl group or an alkoxy group having 1 to 20 carbon atoms. R is a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. * is an asymmetric carbon atom. ]