JP3218426B2 - Liquid crystal element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device used for a light valve used in a flat panel display, a projection display, a printer, and the like.

[0002]

2. Description of the Related Art A CRT is known as the most widely used display. CRT
Is widely used as a moving image output for televisions and VTRs, or as a monitor for personal computers. However, C
Due to the characteristics of RT, when a still image is displayed, flicker or scanning line stripes due to insufficient resolution lowers the visibility, or the phosphor deteriorates due to burn-in. In addition, it has recently been found that the electromagnetic waves generated by the CRT adversely affect the human body, and there is a concern that the health of VDT workers may be impaired. And the CRT is structurally
Since it has a large volume behind the screen, it may hinder space saving in offices and homes, and may not be able to fulfill its responsibility as a display in a highly information-oriented society.

As a solution to such a drawback of the CRT, there is a liquid crystal element. For example, M. Shut (MS
chadt) and W. Helfrich
Frich), "Applied Physics Letters"
s) A liquid crystal device using a twisted nematic liquid crystal disclosed in Vol. 18, No. 4 (issued on Feb. 15, 1971), pp. 127 to 128 is known. When such liquid crystal elements are classified by driving method, one of them is a simple matrix type liquid crystal element which has an advantage in cost. This liquid crystal element has a problem that crosstalk occurs in time-division driving using a matrix electrode structure with a high pixel density, and thus the number of pixels is limited. In addition, since the response speed is as slow as several tens of milliseconds, the use as a display has been limited. In recent years, an active matrix type liquid crystal element using a TFT (thin film transistor) or the like has been developed to improve the disadvantages of such a simple matrix type liquid crystal element. This type of liquid crystal element
Since switching elements such as transistors are created for each pixel, the problems of crosstalk and response speed are solved.However, the larger the area, the more industrially it is extremely difficult to create a liquid crystal element without defective pixels. And costly if possible.

In order to improve the disadvantages of the conventional liquid crystal device, a liquid crystal device using a liquid crystal device having bistability has been proposed by Clark and Lagawell (La).
gerwall) (Japanese Unexamined Patent Publication No. Sho 56-56).
107216, U.S. Pat. No. 4,367,924, etc.). As the liquid crystal having the bistability, a ferroelectric liquid crystal which is a chiral smectic liquid crystal exhibiting a chiral smectic C phase or a chiral smectic H phase is generally used. Since the ferroelectric liquid crystal performs inversion switching by spontaneous polarization, it has a very fast response speed and can exhibit a bistable state with memory properties. Furthermore, since it has excellent viewing angle characteristics when used for a display element, it is considered to be suitably used for a high-speed, high-definition, large-area display element or light valve. Also, recently, Chandani, Takezoe and others
Chiral smectic antiferroelectric liquid crystal devices exhibiting three stable states have also been proposed (Japanese Journal of Applied Physics (Japanes)
e Journal of Applied Physs
ics) 27, 1988, L729).

In such a chiral smectic liquid crystal device, for example, when the liquid crystal molecules are aligned using a general rubbed polyimide alignment film, the apparent tilt angle (the two stable states of the liquid crystal molecules) is obtained. The half of the angle between the axes) is generally at most 3 ° to 8 °
Therefore, the transmittance of the liquid crystal element was 3 to 5%, and the contrast was about 10 which was a very low value. In addition, as described in “Structure and Physical Properties of Ferroelectric Liquid Crystal” (Corona Co., Atsuo Fukuzawa, Hideo Takezoe, 1990), generation of zigzag-shaped alignment defects and liquid crystal molecules between upper and lower substrates are caused. There is also a problem that the contrast is significantly reduced due to the twist (called splay alignment). This alignment defect (zigzag defect) is caused by the fact that the layered structure (smectic layer structure) of the liquid crystal sandwiched between a pair of substrates has a two-directional chevron-like (mountain-like) structure (chevron structure). ing. Hanyu et al. Increased the pretilt angle of liquid crystal molecules at the interface of the alignment film to align the chevron structure in one direction, making the splay alignment more elastically unstable than in a uniform state (uniform alignment). Thereby, a zigzag defect is eliminated, and a liquid crystal element having a large contrast is obtained by increasing an apparent tilt angle (Japanese Patent Laid-Open No. 3-252624). However, even if the method of Hanyu et al. Is used, in order to obtain a good driving state, for example, the tilt angle must be set to 16 ° or less, and the tilt angle (22.5 ° There is room for further improvement when compared to (). In addition, the inclination of the smectic layer peculiar to the chevron structure also lowers the transmittance, and causes a reduction in contrast.

On the other hand, recently, a chevron structure which is a cause of low contrast has been eliminated, and a layered structure called a bookshelf (hereinafter, this structure is referred to as a bookshelf structure),
Alternatively, there has been a movement to realize a structure close to that and realize high contrast (for example, "Next Generation Liquid Crystal Display and Liquid Crystal Materials", edited by CMC, Atsuo Fukuda, 1992). As a means for realizing such a structure, there is a method using a naphthalene-based liquid crystal material. In this case, the tilt angle is about 10 °, which is smaller than 22.5 ° at which an ideal maximum transmittance can be obtained. Very small,
There is a problem that the transmittance becomes low. Moreover,
There is also a problem that the bookshelf structure cannot be reversibly exposed to temperature. Another typical method is to induce a bookshelf structure by applying a high electric field from outside to a liquid crystal device having a chevron structure, but this method also has a problem of instability to external stimuli such as temperature. It has become. A liquid crystal having a bookshelf structure has only recently been discovered in recent years, and there are various other problems for practical use.

Further, as a component of a liquid crystal composition exhibiting a bookshelf structure or a structure similar thereto, a liquid crystal compound having a fluorocarbon terminal portion has been proposed (US Pat. No. 5,262,082, International Application Publication WO 93/93).
22396, 1993 4th International Conference on Ferroelectric Liquid Crystals, P
-46, Mark D.C. Radcliffe et al.).
By mixing this liquid crystal compound with an optically active compound, a bookshelf structure or a structure with a small layer tilt angle close thereto can be exhibited without using an external field such as an electric field. Suitable for liquid crystal elements and liquid crystal devices with a large area. However, further improvements are required in terms of the speed, alignment, contrast, drive stability and the like of the liquid crystal element.

[0008]

In particular, in a liquid crystal device using a liquid crystal composition having the bookshelf structure or a structure close to the bookshelf structure, the apparent tilt angle θa is optimized and enlarged to about 22.5 °. When trying to achieve high brightness, the viscosity of the liquid crystal composition increases,
The slow response of the electric field is a new problem.

It is known that the response of a molecule of a chiral smectic liquid crystal is represented by the following equation (1) by the spontaneous polarization Ps of the liquid crystal and an external electric field E.

Τ = η / PsE Equation (1) where τ is a time constant of response of the liquid crystal to an electric field, and η is a resistance coefficient called switching viscosity. Therefore, in order to overcome the increased viscosity due to the tilt angle optimization for high brightness, it is necessary to increase the spontaneous polarization Ps in the molecular design of the liquid crystal (it is effective to increase the electric field to some extent). However, since the increase in the driving voltage is limited by power consumption, heat generation, and the like, it is realistic to increase the spontaneous polarization Ps of the liquid crystal.)

In the case where the spontaneous polarization of the liquid crystal is increased, problems such as the occurrence of hysteresis in the inversion threshold value between the two states and the reduction of the liquid crystal driving margin at lower temperatures due to the temperature dependence of the spontaneous polarization occur. I will. This means that accumulation of impurity ions and the like in the liquid crystal occurs at the interface between the liquid crystal and the alignment control film / electrode, and as a result, the following formula (2)
It is considered that the cause is that the anti-electric field component shown in (3) is induced and the electric field response of the liquid crystal molecules is inhibited.

V _reverse = [− 2Ps / (C _i + C _lc )] exp (t / τ) Equation (2) where Ps is the spontaneous polarization of the liquid crystal, and C _i and C _lc are the alignment control film and the liquid crystal layer, respectively. Is the time constant determined from the combined capacitance of the liquid crystal layer and the alignment control film, that is, the relaxation time of the anti-electric field component. The resistance of the alignment control film and the liquid crystal layer is represented by R _i ,
When represented by R _lc , τ = CR = (C _i + C _lc ) / [(1 / R _i ) + (1 / R _lc )] Equation (3) Therefore, the attenuation process of the anti-electric field of the liquid crystal depends on the resistance of the interface of the liquid crystal electrode as expressed by the above equation (2), and the effect of the anti-electric field is reduced by reducing the resistance of the alignment control film. Becomes possible.

In general, in order to align a chiral smectic liquid crystal, a polymer film having a horizontal or inclined orientation such as polyimide (PI) or polyamide (PA) is formed on a substrate surface and rubbed in substantially the same direction. A pair of substrates is used. These electrical properties are 1 × 10 ¹⁰ Ωc at room temperature.
This is an insulating film having a resistance value of m or more, and an anti-electric field induced in an electric field response of a liquid crystal having a high spontaneous polarization causes a problem in switching characteristics.

As a method for solving the above-mentioned problems, use of a conductive polymer for an orientation control film is expected. Lowering the resistance of the alignment control film, in addition to the above-described objects, can prevent electrostatic charging of the alignment control film generated during the rubbing process, prevent adsorption of charged foreign substances, and further, have bistability. The chiral smectic liquid crystal has a great merit such as improvement of memory property and realization of uniform alignment by delocalizing local charge bias on the film surface.

As an example of lowering the resistance of the orientation control film, a π-conjugated conductive polymer film using polyaniline (Japanese Patent Laid-Open No.
US Pat. No. 5,231,523), one containing conductive fine particles dispersed in a polymer matrix (Japanese Patent Laid-Open No. 3-92824), and one containing a charge transfer complex (US Pat. No. 5,231,523). ) Etc. are proposed,
All of them have the following problems as alignment control films for liquid crystal elements.

When the π-conjugated polymer film is in an undoped state, it is an insulating film similarly to polyimide and the like, and requires an acid, alkali, or electrochemical doping process to reduce the resistance. These post-treatments not only complicate the manufacturing process, but also pose a problem that the liquid crystal layer and the transparent electrode wiring may be contaminated or corroded by a dopant.

In the case where such conductive fine particles are dispersed, the fine particles and the surrounding binder film are liable to peel off at the time of rubbing, and there is a problem that the portion may become an alignment defect.

On the other hand, in the case where the charge transfer complex is dispersed as described above, there is a problem in that thermal instability of the complex and a sudden increase in resistance when the complex is mixed into the orientation control film are caused.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the resistance of an alignment control film to thereby prevent adsorption of charged foreign substances on the alignment control film. It is to provide a highly reliable liquid crystal element.

It is another object of the present invention to provide a liquid crystal device exhibiting good switching characteristics by suppressing the influence of an anti-electric field in a liquid crystal device using a liquid crystal exhibiting a chiral smectic phase.

Another object of the present invention is to provide a high-contrast, high-brightness chiral smectic liquid crystal device having a bookshelf structure in which an anti-electric field greatly affects the switching characteristics or a structure with a small layer tilt angle close thereto. It is an object of the present invention to realize high-speed switching, which has been difficult, and to provide a liquid crystal device with high speed drawing, high luminance, and high contrast, particularly a liquid crystal display device using the element.

Further, the present invention reduces the influence of an anti-electric field, which has been a major problem in a liquid crystal device using a liquid crystal composition containing a liquid crystal compound having a fluorocarbon terminal as described above, by controlling the composition of the alignment control film. To achieve a liquid crystal element exhibiting good switching characteristics.

[0023]

The present invention relates to a liquid crystal element having a liquid crystal composition sandwiched between a pair of substrates, wherein at least one of the pair of substrates has an alignment on a surface in contact with the liquid crystal composition. control film is formed, the alignment control film Po
A liquid crystal device characterized by comprising a mixed film of polyamide and polypyridine polymer.

[0024]

[0025]

With this configuration, the resistance of the orientation control film can be reduced without performing any of chemical doping, electrochemical doping, addition of a charge transfer complex, and addition of conductive fine particles to the orientation control film. Can be achieved.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to an alignment control film (alignment film).
In order to solve the above-mentioned problem that is an obstacle in lowering the resistance of a polymer, a polymer having conductivity (hereinafter abbreviated as a polymer of type N) and a polymer having an insulating property (hereinafter, type P) The polymer is abbreviated as above) to form an alignment control film, thereby realizing low resistance and uniform alignment of the alignment control film without going through a doping process.

[0028] as a polymer of the type P, the electric children given of the polymer is preferably a polymer that does not have a π-conjugated system, and further consideration of the orientation of the liquid crystal, is needed use is made of Polyamide.

Further, as the polymer type N, preferably electron-accepting polymer, Poripiri having π-conjugated system
Jin polymer, i.e. polypyridine and its derivatives are needed use.

In the present invention, the conductivity of the orientation control film composed of the type N polymer and the type P polymer is higher than the conductivity of the film composed of the type N polymer alone. In a combination in which the polymer of type N has a π-conjugated system and the polymer of type P does not have a π-conjugated system,
The optical absorption based on the π-π ^* transition per 1π bond of the polymer having a π conjugate system is increased by adding a polymer having no π bond.

[0031] In the present invention, from the viewpoint of mixed-is easy, Ru used in combination with polyamide and polypyridine or a derivative thereof.

Although the details of the mechanism for lowering the resistance in the present invention have not been clarified, it is inferred that the lowering of resistance has been achieved due to the following factors .

Factor 1 (Efficient generation of conductive carriers due to charge transfer between both resins) Since polypyridine has a high oxidation potential due to the strong electronegativity of the lone pair of electrons in the nitrogen of the pyridine ring, polypyridine is a cation such as Pd. Can only dope. That is, it is considered that the polyamide is in an electron-rich state by attracting electrons from the polyamide side, while the polyamide is in a proton-rich state, when mixed with a polyamide such as nylon because it is not easily oxidized and easily reduced.

Table 1 shows the absorbance at around 490 nm based on the π-π ^* transition of a dispersion mixed film of nylon 66 and polythiophene pyridine, based on the thiophene pyridine ring (—C ₄ H ₂ S—C _5).
The values normalized by the H ₃ N-) concentration are shown with respect to the blend weight ratio. Since this absorbance corresponds to the carrier concentration (electron concentration) distributed on the main chain of polythiophene pyridine, in this blend system, the polythiophene pyridine is polarized due to the inclusion of nylon, and the carrier concentration is higher than that of the polythiophene pyridine monolayer. An increase in concentration was observed.

[0035]

[Table 1]

Factor 2 (Developed Carrier Conduction Path) As is well known, polypyridine and its derivative polymers are π-conjugated polymers and have a conjugated electron conduction path developed on the main chain. I have. On the other hand, polyamide resins such as nylon 66 are generally known as insulators, but are known to be proton (H ⁺ ) conductive under an electric field of about 300 V / cm ( S. Saito, Reports on Progr
ess in Polymer Physics in
Japan, XII, 411 (1969); A.
Seeornor, J. et al. Polymer. Sci. A-2,
6,463 (1968)). For this reason, even if both resins are mixed, it is considered that the conduction paths of the generated carriers are mutually guaranteed without being divided.

As described above, it is considered that as if both polymers functioned like a polymer charge-transfer complex, the resistivity of each polymer was lower than that of a single polymer by mixing.

The polypyridine-based polymer and the polyamide-based polymer also have excellent orientation in the uniform orientation of the chiral smectic liquid crystal. Among them, the nylon-based polyamide-based polymer having a methylene chain in its main chain is particularly preferred. The polymer is excellent in aligning a liquid crystal composition containing the above-mentioned liquid crystal compound having a fluorocarbon terminal. In addition, since both use m-cresol, formic acid or the like as a common solvent, they have an advantage that they are easily mixed even in a process.

Although the present invention has a particularly remarkable effect in improving the switching characteristics of a highly spontaneously polarized chiral smectic liquid crystal having a bookshelf structure or a layer structure close thereto, a chiral smectic having a chevron structure Liquid crystals are also effective in improving the switching characteristics particularly at low temperatures. Further, the present invention can be effectively used in liquid crystal elements other than the chiral smectic liquid crystal in order to reduce the resistance of the alignment film.

The liquid crystal device according to the present invention will be described below with reference to examples.

FIG. 1 shows a configuration example of the liquid crystal element of the present invention. In the liquid crystal device of the present invention, the glass substrate 11a,
11b, the transparent electrodes 12a and 12b and the orientation control film 14
a and 14b are formed, and at least one of the alignment control films 14a and 14b is a mixed film of the above-mentioned type N and type P polymers. Preferably, polypyridine type P is poly <br/> amino-de having a repeating unit of the structure represented by the following general formula P-1, type N is having repeating units of the structure represented by the following general formula P-2 It is a system polymer.

Formula P-1 —CONH— (CH ₂ ) _n —NHCO— (CH ₂ ) _m —Formula P-2-AB— (wherein m and n are the same or different and 1 to 1
Any integer of 2. A is a pyridine ring and the bond position with B is at the 2- or 5-position, and B is any of a pyridine ring, a thiophene ring, a pyrrole ring, a fluorenone ring, an isothianaphthene pyridine ring, a furan ring, and a thiophene pyridine ring. , A thiophene ring or a pyrrole ring, the proton at the 3- or 4-position has an alkyl group, an alkoxy group, a carboxylate group, a phenyl group, a naphthyl group, an anthracene group.
And may be substituted with an yl group. )

[0043] Here, the polymerization degree of polyamide-de having a repeating unit of structure represented by P-1 is preferably 1000 to 100,000 in consideration the orientation control performance and solubility. The degree of polymerization of the polypyridine-based polymer having the repeating unit having the structure represented by P-2 is preferably from 100 to 100,000, more preferably from 1,000 to 50,000, in consideration of the ability to control the orientation and the solubility.

In the present invention, the weight ratio between the polyamide and the polypyridine-based polymer is 5:
95:45:55, preferably 15:85
More preferably, the ratio is 35:65.

In the present invention, the orientation control film 14 is used.
Insulating films 13a and 13b in which silicon oxide, tantalum oxide, or the like is provided by sputtering or vapor deposition may be provided between the transparent electrodes 12a and 12b.

The above substrate is used as a spacer 16 made of silica beads or the like.
Are bonded using a sealing material through to form a cell. The liquid crystal composition 15 is injected into this cell by using a capillary phenomenon or the like, whereby the liquid crystal element of the present invention is manufactured.

As the liquid crystal composition 15, a nematic liquid crystal composition, a chiral smectic liquid crystal composition, or the like is used. Particularly, by using the chiral smectic liquid crystal composition, a great effect can be obtained in terms of suppressing an anti-electric field.

In the present invention, the liquid crystal composition to be used preferably has a fluorocarbon terminal portion and a hydrocarbon terminal portion, and the both terminal portions are bound by a central nucleus and have a smectic intermediate phase or a potential smectic intermediate phase. Those containing a fluorine-containing liquid crystal compound are desirable.

In general, the fluorine-containing liquid crystal compound used in the present invention has a central nucleus, and the central nucleus has at least two aromatic rings, heteroaromatic rings, aliphatic rings, or substituted aromatic rings. Or a substituted aliphatic ring, and these rings are mutually -COO-, -COS-, -HC = N-,-
It may be bonded by a functional group selected from COSe-. These rings may be fused or unfused. Heteroatoms in the heteroaromatic ring include at least one atom selected from N, O, or S. Non-adjacent methylene groups in the aliphatic ring may be replaced by O.

In the fluorine-containing liquid crystal compound, the terminal portion of the fluorocarbon is a group represented by -D ¹ -C _xa F _2xa -X (provided that xa is 1 to 20;
It represents -H or -F, D ¹ is, -CO-O- (C
_{H 2) ra -, - O-} (CH 2) ra -, - (CH 2) ra -,
_{-O-SO 2 -, - SO} 2 -, - SO 2 - (CH 2) ra -,
_{-O- (CH 2) ra -O- (} CH 2) rb -, - (CH 2)
_{ra -N (C pa H 2pa +} 1) -SO 2 -, or - (CH _{2) ra
-N (C pa H 2pa + 1} ) represents the -CO-. ra and rb
Is independently 1 to 20, and pa is 0 to 4. ),
Alternatively, a group represented by -D ^2- (C _xb F _2xb -O) _za -C _ya F _{2ya + 1} (where xb is each of (C
_xb F _2xb -O) is independently 1 to 10, and ya is 1 to
10, za is 1 to 10, and D ² is -CO-
_{O-C rc H 2rc, -O} -C rc H 2rc -, - C rc H 2rc -,
_{-O- (C sa H 2sa -O)} ta -C rd H 2rd -, - O-SO
_{2 -, - SO 2 -,} - SO 2 -C rc H 2rc -, - C rc H 2rc
_{-N (C pb H 2pb + 1} ) -SO 2 -, - C rc H 2rc -N (C
_pb H _2pb + 1) -CO-, selected from a single bond, rc and r
d is independently 1 to 20, sa is independently 1 to 10 for each (C _sa H _2sa -O), and ta is 1
And pb is 0-4. ) Can be used.

Particularly preferably, a fluorine-containing liquid crystal compound represented by the following general formula (I) or (II) can be used.

[0052]

Embedded image Represents

Ga, ha and ia each independently represent an integer of 0 to 3 (provided that ga + ha + ia is at least 2).

Each of L ¹ and L ² is independently a single bond, —CO
-O-, -O-CO-, -COS-, -S-CO-,-
CO-Se-, -Se-CO-, -CO-Te-, -T
_{e-CO -, - CH 2} CH 2 -, - CH = CH -, - C≡
C -, - CH = N - , - N = CH -, - CH 2 -O-,
-O-CH ₂ -, - CO- or represent -O-.

Each of X ¹ , Y ¹ and Z ¹ is a substituent of A ¹ , A ² and A ³ and independently represents —H, —Cl, —F, —Br,
_{I, -OH, -OCH 3, -CH} 3, -CN, or -NO
₂ and each of ja, ma and na independently represents an integer of 0-4.

J ¹ is —CO—O— (CH ₂ ) _ra —, —O
_{- (CH 2) ra -,} - (CH 2) ra -, - O-SO 2 -,
_{-SO 2 -, - SO 2 -} (CH 2) ra -, - O- (CH 2)
_{ra -O- (CH 2) rb -} , - (CH 2) ra -N (C pa H
_2pa + 1) -SO ₂ -, or _{- (CH 2) ra -N (} C pa H
_{2pa + 1} ) represents -CO-. ra and rb are independently 1
-20 and pa is 0-4.

R ¹ is _{-OC qa} H _{2qa -OC qb} H
_{2qb + 1, -C qa H 2qa} -O-C qb H 2qb + 1, -C qa H 2qa -
_{^{R 3, -O-C qa H}} 2qa -R 3, -CO-O-C qa H 2qa -
R ³ or —O—CO—C _qa H _2qa —R ³ , which may be linear or branched (where R ³ _{is-
O-CO-C qb H 2qb} + 1, -CO-O-C qb H 2qb + 1, -
_{H, -Cl, -F, -CF 3} , -NO 2, represents a -CN, qa and qb are 20 independently).

R ² represents C _xa F _2xa -X (X represents -H or -F, and xa is an integer of 1 to 20).

[0059]

Embedded image Represents

Gb, hb and ib are each independently 0 to 3
(Where gb + hb + ib is at least 2).

Each of L ³ and L ⁴ is independently a single bond, -CO
-O-, -O-CO-, -CO-S-, -S-CO-,
-CO-Se-, -Se-CO-, -CO-Te-,-
Te-CO -, - (CH 2 CH 2) ka - (ka is 1
4), -CH = CH-, -C≡C-, -CH = N-,-
_{N = CH -, - CH 2} -O -, - O-CH 2 -, - CO-
Or -O-.

Each of X ² , Y ² and Z ² is a substituent of A ⁴ , A ⁵ and A ⁶ and independently represents —H, —Cl, —F, —Br,
_{I, -OH, -OCH 3, -CH} 3, -CF 3, -O-C
F ₃ , —CN, or —NO ₂ , and each jb, m
b and nb each independently represent an integer of 0 to 4;

J ² is —CO—O—C _rc H _2rc —, —O—
_{C rc H 2rc -, - C} rc H 2rc -, - O- (C sa H 2sa -
O) _ta -C _rd H _2rd- , _-O -SO _2- , -SO ₂ -,-
_{SO 2 -C rc H 2rc -,} - C rc H 2rc -N (C pb H 2pb + 1)
_{-SO 2 -, - C rc H} 2rc -N (C pb H 2pb + 1) -CO-
_Where rc and rd are independently 1-20, sa is independently 1-10 for each (C _sa H _2sa -O), ta is 1-6, pb is 0-4. is there.

R ⁴ is -O- (C _qc H _2qc -O) _wa- C _{qd
H 2qd + 1, - (C} qc H 2qc -O) wa -C qd H 2qd + 1, -C
_qc H _2qc -R ⁶ , _{-OC qc} H _2qc -R ⁶ , -CO- _OC
qc H _2qc -R ^6, or represents _{-O-CO-C qc H 2qc} -R 6, linear, may be either branched (Here, R
⁶ is _{-O-CO-C qd H 2qd} + 1, -CO-O-C qd H
_{2qd + 1, -Cl, -F,} -CF 3, -NO 2, represents -CN, or -H, qc and qd are independently an integer of 1 to 20, the wa is an integer of 1 to 10).

R ⁵ is (C _xb F _2xb -O) _za -C _ya F
_{2ya + 1} is represented by (wherein, the formula xb is 1 to 10 independently of each _{(C xb F 2xb -O),} ya is 1
And za is 1-10).

The compound represented by the above general formula (I)
JP-A-2-142755, U.S. Pat.
2,587.
Specific examples of such compounds are listed below.

[0067]

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[0068]

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[0069]

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[0070]

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[0071]

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[0072]

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[0073]

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[0074]

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[0075]

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[0076]

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[0077]

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[0078]

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The compound represented by the above general formula (II) is described in WO 93/22396, JP-T-Hei 7-506.
368 can be obtained.
Specific examples of such compounds are listed below.

[0080]

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[0081]

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[0082]

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[0083]

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[0084]

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The chiral smectic liquid crystal composition used in the present invention contains, for example, a compound having a chiral moiety as shown below.

[0086]

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[0087]

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[0088]

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[0089]

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[0090]

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[0091]

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[0092]

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[0093]

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[0094]

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[0095]

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These compounds are used as a matrix of a chiral smectic liquid crystal composition in the form of a single compound or a mixture of plural compounds.

In the chiral smectic liquid crystal composition used in the present invention, various other liquid crystal compounds including chiral compounds and achiral compounds other than those described above are appropriately selected according to the control of the compatibility between the compounds and the layer spacing. Used. In particular, the compound having a fluorocarbon terminal as described above is used as an essential component, and the compounding ratio of the chiral compound is appropriately set according to the type. For example, the chiral compound is blended in a range of about 0.5 to 50% by weight.
When a compound having no fluorine-based terminal portion is used as the chiral compound, the mixing ratio of the chiral compound is 0.1 to 10% by weight in consideration of compatibility with the compound having a base fluorocarbon terminal portion. It is preferable that Also antioxidants, UV absorbers, dyes,
An additive such as a pigment may be contained.

[0098] made of Polyamide, which then represented by the general formula P-1
The structural formula example of a repeating unit is shown.

[0099]

Embedded image

Next, structural examples of the repeating unit of the polypyridine polymer represented by the general formula P-2 will be shown.

[0101]

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[0102]

EXAMPLES Specific examples and comparative examples are shown below. First, each evaluation method in this example and a comparative example will be described.

[Evaluation of Uniform Orientation] Orientation (Normal direction of layer)
The uniformity of T was obtained by measuring the transmittance in the darkest state in the SmA phase by measuring the polarization axes of the analyzer and the polarizer with crossed Nicols, and standardizing the transmission light amount when the polarization axes of the analyzer and the polarizer were paranicoles. _The evaluation was performed using the parameter _d . This is 100%
It is desirable that the absolute value be small, with the upper limit being.

T _d = I _c / I _p I _c = the darkest transmitted light quantity when the polarizer-analyzer is crossed Nicol I _p = the darkest transmitted light when the polarizer-analyzer is paranicol Transmitted light amount [Evaluation of film resistivity] Corning's # 7059 substrate was subjected to ultrasonic cleaning with trichloroethylene, acetone, ethanol, and pure water respectively, and finally washed with pure water and dried under a dry nitrogen atmosphere. After preparing and sintering an alignment control film material solution on the substrate to a thickness of 100 ° by spin coating or the like, a comb-shaped counter-shaped gold electrode is vapor-deposited by resistance heating at 300 °, and the resistance in the sheet direction is set. The measurement was performed to determine the volume resistance (temperature: 25 ° C., humidity: 55%). Further, a volume resistance is determined by coating and baking an orientation control film to a thickness of 1000 ° by a method similar to the above using a substrate obtained by vapor-depositing ITO on a 7059 substrate manufactured by Corning Co., Ltd. Electrode 300 by resistance heating evaporation
It can also be determined by measuring the resistance in the film thickness direction by forming with Å.

[Evaluation of Driving Characteristics] In addition, the evaluation of the influence of the anti-electric field on the electric field response of the liquid crystal was performed at 10 ° C. by applying an operation pulse including a reset pulse and a bipolar pulse shown in FIG.
A voltage of ₁ and V ₄ is applied to the 1-second intervals while changing the 0V → 40V → 0V at 4V / min, V ₄ is applied after the end of 800
The transmittance at msec was determined, and the inversion threshold voltage was determined from the 50% transmission condition of the resulting voltage-transmittance curve.
At this time, the inversion threshold voltage in the process of 0V → 40V is V ₁₂ , and the inversion threshold voltage in the process of 40V → 0V is V ₂₁
The hysteresis voltage is defined as the difference V _H = V ₁₂ −V ₂₁ between the inversion thresholds when

[Example 1] The liquid crystal element of this example was manufactured as follows.

A Corning # 7059 substrate was ultrasonically washed with trichloroethylene, acetone, ethanol, and pure water, and finally washed with pure water, dried in a dry nitrogen atmosphere, and dried with nylon 66 having a polymerization degree of 5000. And a mixed formic acid solution of polythiophene pyridine (PTpy) having a polymerization degree of 2000 was spin-coated. As a coating solution, a 0.5% by weight formic acid solution prepared by adjusting the solid content ratio of nylon 66 and PTpy to 25:75 was prepared. Spin conditions were set at 2000 rpm for 20 seconds. This substrate is
After drying the solvent in an oven at 0 ° C. for 5 minutes,
The heating and firing were performed in an oven at 0 ° C. for one hour. The thickness of the obtained mixed film was about 100 °.

Next, after a tooth-shaped gold electrode was provided on the obtained film by about 300 ° by a resistance heating evaporation method, the resistance value was measured by a minute ammeter. At this time, the volume resistance is 5 × 10 ⁷ Ω
cm.

Next, a transparent electrode was formed by sputtering.
A pair of glass substrates on which ITO (indium tin oxide) having a thickness of 00 mm was formed was prepared, and one of the substrates was spin-coated with the above mixed formic acid solution. This substrate is heated at 80 ° C.
After drying the solvent in the oven for 5 minutes, it was heated and baked in an oven at 180 ° C. for 1 hour. The obtained mixed film is about 1
With a thickness of 00mm, the roller is pressed into this membrane 0.4m
m, roller rotation speed 1000 rpm, substrate feed speed 5 m
Rubbing treatment was performed three times at m / sec. The roller was formed by winding a nylon cloth around a roller having a diameter of 8 cm.

Then, an IPA (isopropyl alcohol) solution in which silica beads having an average particle size of 2.0 μm were dispersed at 0.01% by weight on the surface of the one substrate was 1500
rpm, spin coating under the condition of 10 seconds, distribution density 300
Bead beads spacers of about pieces / mm ² were sprayed.

A 0.5% by weight ethanol solution of a silane coupling agent (ODS-E) was applied to the opposite substrate.
The coating was performed with a spinner under the conditions of 00 rpm and 20 seconds, and a vertical alignment treatment was performed. Then, it was dried in an oven at 180 ° C. for 1 hour. A thermosetting liquid adhesive was applied to the substrate by a printing method.

The two substrates thus obtained were adhered to each other and thermally cured in an oven at 150 ° C. for 90 minutes to form a cell.

The liquid crystal composition described below was injected into this cell under reduced pressure (10 Pa) at an isotropic phase temperature (100 ° C.).
The liquid crystal element was obtained by gradually cooling to the SmC ^* phase.

The mixed liquid crystal composition used in this example is shown below.

Weight ratio: Compound A / B / C / D / E = 4
6.4 / 15.5 / 30.9 / 5.2 / 2.0

[0116]

Embedded image

[0117]

Embedded image

The physical parameters of this composition are shown below.

[0119]

(Equation 1)

The measuring methods of the tilt angle and the spontaneous polarization are as follows.

[Measurement of tilt angle] ± 30 to ± 50 V,
While applying an AC (alternating current) of 1 to 100 Hz between the upper and lower substrates of the liquid crystal element via electrodes, the liquid crystal element disposed therebetween is rotated in parallel with the polarizing plate under crossed Nicols, and at the same time, the photomultiplier ( The first extinction position (the position where the transmittance becomes lowest) and the second extinction position are obtained while detecting the optical response with Hamamatsu Photonics Co., Ltd. The angle of the angle from the first extinction position to the second extinction position at this time is 1
/ 2 is the tilt angle.

[Method of Measuring Spontaneous Polarization]
Miyasato et al., "Direct Measurement Method of Spontaneous Polarization of Ferroelectric Liquid Crystal by Triangular Wave" (Journal of the Japan Society of Applied Physics 22, 10 (66)
1) 1983, "Direct Method wit
h Triangular Waves for Me
asuring Spontaneous Polar
Ization in Ferroelectric L
liquid Crystal ", as descri
bed by K. Miyasato et al (J
ap. J. Appl. Phys. 22. No. 10, L
661 (1983))).

The above chiral smectic liquid crystal cell was placed on an FP82 hot stage controlled by a Mettler FP80HT temperature controller, and the temperature was reduced from the isotropic phase (90 ° C.) to the SmA phase (50 ° C.) at a rate of −1 ° C./min. The darkest state in the SmA phase was obtained under crossed Nicols, and the transmittance thereof was measured. As a result, the transmittance under paranicol was 100%, and _Td was 0.50%. When the inversion threshold was measured at 10 ° C. with a variable voltage having a pulse width of 20 μsec, the inversion threshold V ₁₂ and the inversion threshold V were measured.
The difference (V _H ) of ₂₁ was 0.3V.

[Comparative Example 1] # 7059 manufactured by Corning Incorporated
A substrate was prepared by cleaning it in the same manner as in Example 1,
A 1.0% by weight formic acid solution of nylon 66 having a degree of polymerization of 5,000 was spin-coated on the substrate. Spin condition is 300
The test was performed at 0 rpm for 20 seconds. After drying the substrate in an oven at 80 ° C. for 5 minutes, the substrate was heated and baked in an oven at 180 ° C. for 1 hour. The thickness of the obtained mixed film was about 100 °.

Next, a comb-shaped gold electrode was provided on the obtained film by about 300 ° by a resistance heating evaporation method, and the resistance value was measured by a microammeter. At this time, the volume resistance is 2 × 10 ¹⁰
Ωcm.

Next, as in Example 1, a pair of glass substrates on which transparent electrodes were formed were prepared, and the nylon 66 film was formed on one of the substrates under the above-described conditions. After the treatment, the other substrate was subjected to the same vertical alignment treatment as in Example 1 to produce a cell.

The liquid crystal composition used in Example 1 was injected into the cell under reduced pressure (10 Pa) at an isotropic phase temperature (100 ° C.), and was gradually cooled to an SmC ^* phase to obtain a liquid crystal element.

When the transmittance of this liquid crystal cell in the darkest state was measured in the same manner as in Example 1, it was found that T _d was 0.45%. When the inversion threshold was measured at 10 ° C. with a variable voltage having a pulse width of 20 μsec, V _H was 1.5 V
Met.

[Comparative Example 2] Corning's # 7059
A substrate was prepared by cleaning it in the same manner as in Example 1,
A 1.0 wt% formic acid solution of PTpy was applied on the substrate. Spin conditions were 1000 rpm for 20 seconds. After drying the substrate in an oven at 80 ° C. for 5 minutes, the substrate was baked for 1 hour in an oven at 180 ° C.
The thickness of the obtained mixed film was about 100 °.

Next, a comb-shaped gold electrode was provided on the obtained film by about 300 ° by a resistance heating evaporation method, and the resistance value was measured by a microammeter. At this time, the volume resistance is 9 × 10 ⁹
Ωcm.

Next, as in Example 1, a pair of glass substrates on which transparent electrodes were formed were prepared, and the PTpy film was formed on one of the substrates under the above-described conditions. Then, the other substrate was subjected to the same vertical alignment treatment as in Example 1 to produce a cell.

The liquid crystal composition used in Example 1 was injected into this cell under reduced pressure (10 Pa) at an isotropic phase temperature (100 ° C.), and was gradually cooled to an SmC ^* phase to obtain a liquid crystal element.

When the transmittance of this liquid crystal cell in the darkest state was measured in the same manner as in Example 1, T _d was 1.85%. When the inversion threshold was measured at 10 ° C. with a variable voltage having a pulse width of 20 μsec, V _H was 1.0 V
Met.

[Comparative Example 3] Corning's # 7059
A substrate was prepared by cleaning it in the same manner as in Example 1,
On that substrate, a mixed solution of polyamic acid LP64 (manufactured by Toray Industries, Ltd.), which is a precursor of polyimide, and NMP (N-methylpyrrolidone): nBC (n-butyl cellosolve) was spin-coated. The coating solution was adjusted to a mixed solution of NMP: nBC = 2: 1 with 1.0% by weight of LP64, and spinning was performed at 2700 rpm for 20 seconds. After drying the substrate in an oven at 80 ° C. for 5 minutes, the substrate was baked for 1 hour in an oven at 200 ° C. to imidize the substrate. The thickness of the obtained polyimide film is about 1
It was 00 $.

Next, a comb-shaped gold electrode was provided on the resulting film by about 300 ° by a resistance heating evaporation method, and the resistance value was measured by a microammeter. At this time, the volume resistance is 2 × 10 ¹¹
Ωcm.

Next, as in Example 1, a pair of glass substrates on which transparent electrodes were formed were prepared, and the polyimide film was formed on one of the substrates under the above-described conditions. Then, the other substrate was subjected to the same vertical alignment treatment as in Example 1 to produce a cell.

The liquid crystal composition used in Example 1 was injected into this cell under reduced pressure (10 Pa) at an isotropic phase temperature (100 ° C.), and was gradually cooled to an SmC ^* phase to obtain a liquid crystal element.

When the transmittance of this liquid crystal cell in the darkest state was measured in the same manner as in Example 1, it was _Td = 0.07%. When the inversion threshold was measured at 10 ° C. with a variable voltage having a pulse width of 20 μsec, V _H was 2.0 V
Met.

Table 2 shows the results of Example 1 and Comparative Examples 1 to 3.

[0140]

[Table 2]

Example 2 # 7059 manufactured by Corning Incorporated
A washed substrate was prepared in the same manner as in Example 1, and a mixed formic acid solution of nylon 66 and polypyridine (Ppy) having a degree of polymerization of 5,000 was spin-coated on one of the substrates. As a coating solution, a 0.5% by weight formic acid solution prepared by adjusting the solid content ratio of nylon 66 to Ppy to 25:75 was prepared.
Spin conditions were set at 2000 rpm for 20 seconds. The substrate was dried in an oven at 80 ° C. for 5 minutes and then baked in an oven at 180 ° C. for 1 hour. The thickness of the obtained mixed film was about 100 °.

Next, a comb-shaped gold electrode was provided on the obtained film by about 300 ° by a resistance heating evaporation method, and the resistance value was measured by a microammeter. At this time, the volume resistance is 9 × 10 ⁷
Ωcm.

Next, as in Example 1, a pair of glass substrates on which transparent electrodes were formed were prepared, the mixed film was formed on both substrates under the above-described conditions, and the same rubbing treatment as in Example 1 was performed. Then, they were bonded to each other so that the rubbing directions were antiparallel to each other, thereby producing a cell.

The liquid crystal composition used in Example 1 was injected into this cell under reduced pressure (10 Pa) at an isotropic phase temperature (100 ° C.), and only one of the substrates was rapidly cooled ^.
The liquid crystal element was obtained by gradually cooling to the phase.

When the transmittance of this liquid crystal cell in the darkest state was measured in the same manner as in Example 1, it was _Td = 0.50%. When the inversion threshold was measured at 10 ° C. with a variable voltage having a pulse width of 20 μsec, V _H was 0.5 V
Met.

[Comparative Example 4] # 7059 manufactured by Corning Incorporated
A substrate was prepared by cleaning it in the same manner as in Example 1,
A 1.0% by weight formic acid solution of nylon 6 having a degree of polymerization of 5000 was applied onto the substrate. Spin conditions are 2000 rpm,
Performed in 20 seconds. This substrate is placed in an oven at 80 ° C. for 5 minutes.
After drying the solvent for 1 minute, it was heated and baked in an oven at 180 ° C. for 1 hour. The thickness of the obtained nylon film is about 100
Was Å.

Next, a comb-shaped gold electrode was provided on the resulting film by about 300 ° by a resistance heating evaporation method, and the resistance value was measured by a microammeter. At this time, the volume resistance is 1.5 × 1
It was 0 ¹⁰ Ωcm.

Next, in the same manner as in Example 1, a pair of glass substrates on which transparent electrodes were formed were prepared, the nylon film was formed on both substrates under the above-described conditions, and the same rubbing treatment as in Example 1 was performed. Then, the rubbing directions were opposed to each other so as to be opposite to each other, and a cell was produced.

The liquid crystal composition used in Example 1 was injected into this cell under reduced pressure (10 Pa) at an isotropic phase temperature (100 ° C.), and only one of the substrates was rapidly cooled ^.
The liquid crystal element was obtained by gradually cooling to the phase.

When the transmittance of this liquid crystal cell in the darkest state was measured in the same manner as in Example 1, _Td was 1.5%. When the inversion threshold was measured at 10 ° C. with a variable voltage having a pulse width of 20 μsec, V _H was 2.8 V.

Table 3 shows the results of Example 2 and Comparative Example 4.

[0152]

[Table 3]

[Example 3] A liquid crystal device was prepared in the same manner as in Example 1 except that polypyridine having a polymerization degree of 2000 was used instead of polythiophenepyridine. When the same evaluation as in Example 1 was performed for this liquid crystal element, the volume resistivity was 8 × 10 ⁷ Ωcm. T _d = 0.20%
Met. V _H was 0.3 V.

[0154]

As described above, according to the present invention,
A liquid crystal element having an alignment control film exhibiting good conductivity can be provided. In particular, high-contrast, high-brightness chiral smectic liquid crystal devices having a structure with a small layer tilt angle close to Bookshelf, without introducing conductive fine particles or dopants into the alignment control film, have been conventionally difficult to achieve. In addition, in a liquid crystal device using a liquid crystal compound having a fluorocarbon terminal portion, a liquid crystal device that has solved the conventional problem of an anti-electric field component by controlling the composition of an alignment control film and has excellent switching characteristics. The device has been realized.

[Brief description of the drawings]

FIG. 1 is a sectional view of a cell of a liquid crystal element of the present invention.

FIG. 2 is an explanatory diagram of a driving waveform for measuring a hysteresis amount of an inversion threshold, which is a driving characteristic of the liquid crystal element of the present invention.

[Explanation of symbols]

 11a, 11b Glass substrate 12a, 12b Transparent electrode 13a, 13b Insulating film 14a, 14b Alignment control film 15 Chiral smectic liquid crystal 16 Bead spacer 17a, 17b Polarizing plate

Continued on the front page (72) Inventor Yasuaki Takeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Ikuo Nakazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masanobu Asaoka 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yukio Hanyu 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-6-75226 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1337

Claims (14)

(57) [Claims] 1. A liquid crystal element having a liquid crystal composition sandwiched between a pair of substrates, wherein at least one of the pair of substrates has an alignment control film formed on a surface in contact with the liquid crystal composition, A liquid crystal device, wherein the alignment control film comprises a mixed film of a polyamide and a polypyridine-based polymer. 2. A liquid crystal device according to claim 1, wherein the benzalkonium that having a repeating unit of the structure in which the polyamide is represented by the following general formula P-1. Formula _{P-1 -CONH- (CH 2)} n -NHCO-
(CH ₂ ) _m − (wherein m and n are the same or different and 1 to 1
Any integer of 2. ) 3. The polypyridine polymer according to claim 1, wherein the polypyridine polymer is a polypyridine polymer having a repeating unit having a structure represented by the following general formula P- 2.
3. The liquid crystal device according to item 1. In the general formula P-2-AB-, wherein A is a pyridine ring and the bonding position with B is 2 or 5
And B is any of a pyridine ring, a thiophene ring, a pyrrole ring, a fluorenone ring, an isothianaphthene pyridine ring, a furan ring, and a thiophene pyridine ring. May be substituted with an alkyl group, an alkoxy group, a carboxylic ester group, a phenyl group, a naphthyl group, or an anthracen-yl group. ) 4. A liquid crystal device according to any one of claims 1 to 3 uniaxial aligning treatment in the orientation control layer has been subjected. 5. A liquid crystal device according to any one of claims 1 to 4 liquid crystal composition is a chiral smectic liquid crystal composition. Wherein said liquid crystal composition according to claim has a small structure of a bookshelf structure or near layer inclination 5
The liquid crystal element according to the above. 7. A liquid crystal device according to any one of claims 1 to 6 having the liquid crystal composition is a ferroelectric. 8. A liquid crystal device according to any one of claims 1 to 7 wherein the orientation control film is provided on both of the pair of substrates. 9. The liquid crystal device according to any one of claims 1 to 7 wherein the orientation control film is provided only on one of the pair of substrates. 10. A liquid crystal device according to any one of the made of Polyamide with a polymerization degree of 1,000 or more and 100,000 or less claims 1 to 9. 11. A liquid crystal device according to any one of claims 3 to 1 0 degree of polymerization of 1,000 to 50,000 of the polypyridine polymer. 12. the weight ratio of the polyamide and polypyridine polymer is 5: 95-45: 55 a liquid crystal device according to any one of claims 1 to 1 1. 13. the weight ratio of the polyamide and polypyridine polymer is 15: 85-35: 65 a liquid crystal device according to any one of claims 1 to 1 1. 14. A chemical doping method for the alignment control film,
A liquid crystal device according to any one of claims 1 to 1 3, characterized electrochemical doping, that no even doing one of the addition of charge additive of transfer complex, conductive fine particles.