JPS6332521A - Liquid crystal element - Google Patents

Abstract

PURPOSE:To obtain the titled element having an enlarged tilt angle of the liquid crystal molecule, thereby improving transmissivity at a time of opening a shutter of the picture element, and capable of preventing a flicker of an image plane at a time of multiplexing driving by forming a specific high polymer coated film on at lest one of a pair of substrates which are disposed to parallel with each other. CONSTITUTION:The transparent electrodes 12a and 12b are mounted on an upper and an lower substrates 11a and 11b which are disposed to parallel with each other respectively, and the coated films 14a and 14b composed of the high polymer contg. a CH2 chain and a hetero atom are formed on said substrates respectively. The high polymer compd. is preferably exemplified by polyethers such as polyacetal and polyethylene oxide, et., having a straight chain contg. oxygen or sulfur atom as the hetero atom, and the copolymer of polyethylene oxide and polyacetal may be used to the high polymer compd. A ferroelectric liquid crystal 13 is filled to the space between parallel substrates 11a and 11b. The ferroelectric liquid crystal having bistability is suitable as the liquid crystal 13. The liquid crystal is preferably a Sm* type liquid crystal having a non-spiral structure and >=18 deg. tilt angle. The uniaxially oriented axis is given to the coated films 14a and 14b by rubbing it.

Description

[Detailed Description of the Invention] [Industrial Application] The present invention relates to a liquid crystal element used in a display element, a liquid crystal-optical shutter, etc., particularly a liquid crystal element using a ferroelectric liquid crystal, and more specifically relates to a liquid crystal element using a ferroelectric liquid crystal. The present invention relates to a liquid crystal element with improved display characteristics by improving the initial orientation state of molecules.

(Prior Art) Clark (C18rk) and Lagerwall (C18rk) and Lagerwall (C18rk) display devices utilize the refractive index anisotropy of ferroelectric liquid crystal molecules to control transmitted light in combination with a polarizing element.
wall) (Japanese Patent Application Laid-open No. 107-1983)
No. 216, U.S. Pat. No. 4,367.924, etc.).

This ferroelectric liquid crystal generally exhibits a chiral smectic C phase (SmC") or H phase (SmC") in a specific temperature range.
In this state, it takes either the first optically stable state or the second optically stable state in response to an applied electric field, and maintains that state when no electric field is applied. It has the property of maintaining its stability, that is, bistability, and also has a quick response to changes in electric field, and is expected to be widely used as a high-speed and memory-type display element.

In order for an optical modulation element using this bistable liquid crystal to exhibit predetermined driving characteristics, the liquid crystal disposed between a pair of parallel substrates must be
It is necessary that the molecules be in such a state that conversion between two stable states can occur effectively. For example, for ferroelectric liquid crystals with Sme' or SmH" phases, SmC
It is necessary to form a region (monodomain) in which the liquid crystal molecular phase having the "or SmH" phase is perpendicular to the substrate surface, and the liquid crystal molecular axes are arranged substantially parallel to the substrate surface.

By the way, as a method for aligning ferroelectric liquid crystals, a method using an alignment control film that has been subjected to a glaze-like alignment process, such as a rubbing process or an oblique evaporation process, is generally known.

Most of these conventional alignment methods have been applied to ferroelectric liquid crystals having a helical structure that does not exhibit bistability. For example, the alignment method disclosed in European Patent Publication No. 91661 and Japanese Patent Application Laid-Open No. 60-230635 is based on polyimide, polyamide, or polyvinyl which has been subjected to a ferroelectric liquid crystal rubbing treatment in a helical structure that does not exhibit bistability. The orientation was controlled by an alcohol film.

However, when the conventional alignment control film as described above is applied to control the alignment of a ferroelectric liquid crystal with a non-helical structure exhibiting bistability as proposed by Clark and Lagerwall, there are problems as described below. was.

[Problems to be Solved by the Invention] According to experiments conducted by the present inventors, the tilt angle θ (described later The angle θ shown in Figure 3) is compared with the tilt angle 0 (the angle ■ which is 1/2 of the apex angle of the triangular pyramid shown in Figure 2 below) in a strong-conductivity liquid crystal with a spiral structure. It turned out that it was getting smaller.

In particular, the tilt angle θ of a ferroelectric liquid crystal with a non-helical structure obtained by alignment using a conventional alignment control film is generally about several orders of magnitude, and the transmittance at that time is about 3 to 5% at most.

According to Clark and Lagauer, the tilt angle of a ferroelectric liquid crystal with a non-helical structure that achieves bistability should be the same as the tilt angle of a ferroelectric liquid crystal with a helical structure. However, in reality, the tilt angle e in the non-helical structure is smaller than the tilt angle 0 in the helical structure. That is, in order for the tilt angle θ to take the maximum tilt angle ■, the orientation state of the liquid crystal molecules must be the uniform orientation shown in Figure 4, but in reality, they are adjacent to each other as shown in Figure 5. There was a problem in that it was not possible to form a sufficiently large tilt angle θ because each liquid crystal molecule was twisted and oriented at a twist angle α, resulting in a splay alignment state. In addition, the liquid crystal element under the spray alignment state is
The optical response characteristic to a pulse signal is shown in FIG. 7, and there is a problem in that this optical response characteristic causes flickering on the display screen when multiplexing driving is performed.

It is therefore an object of the present invention to solve the aforementioned problems, namely to increase the tilt angle of a highly conductive liquid crystal with a non-helical structure that achieves at least two stable states, in particular bistability, and to An object of the present invention is to provide a liquid crystal element with improved transmittance when a pixel shutter is opened.

Another object of the present invention is to provide a liquid crystal element that does not cause flickering on the screen during multi-blend shift operation.

That is, according to the present invention, by using a specific alignment control film, it is possible to realize a highly conductive liquid crystal element in a uniform alignment state as shown in FIG. It is possible to realize a liquid crystal element that exhibits optical response characteristics to signals and does not cause flickering on the screen during multiplex leg drive.

The specific orientation control film used in the present invention is formed of a resin film composed of CH2 gold members and heteroatoms, and by using this orientation control film, it is possible to suppress the strong electroconductivity in the uniform orientation state described above. A liquid crystal element can be realized.

[Means for Solving the Problem] and (Operation) That is, the present invention comprises a pair of parallel substrates and an arrangement of molecules forming a plurality of layers perpendicular to the planes of the pair of parallel substrates. In the liquid crystal element having a strong electroconductive liquid crystal, at least one of the pair of parallel substrates is made of a polymer compound having CH2ff1li and a petro atom that preferentially orients the plurality of layers in one direction. It is characterized by a liquid crystal element having a coating.

Specifically, the polymer compound having cH21U and a hetero atom (for example, an oxygen atom, a sulfur atom, etc.) in a straight chain used in the present invention is preferably polyethers such as polyacetal or polyethylene oxide, but other Tetramethylene sulfone, polypentamethylene sulfone.

Polyolefins containing sulfur atoms in the linear chain such as polypentamethylene thioether, polyhexamethylene sulfone, and polyhexamethylene lentioether can be used.

Further, the degree of polymerization of the above-mentioned polymer compound is 5ooo to 5oO.
ooo, preferably 1000 to 100000.

Furthermore, in the present invention, it is also possible to use a copolymer containing two or more of the above-mentioned polymer compounds. Specifically, a copolymer of polyethylene oxide and polyacetal, a copolymer of polytetramethylene sulfone and polypentamethylene sulfone, a polyacetal copolymer, etc. can be used.

In addition, as a method for forming a film using these polyether resins or linear sulfur atom-containing polyolefin resins, the resin is added in an appropriate solvent in an amount of 0.1% to 20% by weight, preferably 0.2% to 20% by weight. A solution dissolved at a ratio of 10% by weight, or a precursor solution thereof, is applied by spinner coating method, dip coating method,
Screen mark El? After coating by methods such as drying, spray coating, and roll coating, the predetermined curing conditions (
For example, a method of curing under heating) can be used.

The solvents used in this case are water and glycol.

Glycerol, piperazine, triethylenediamine, formamide, dimethylformamide.

0-chlorophenol, tetrachloroethane.

Examples include cresol and butyl acetate.

The present invention will be explained in detail below.

FIGS. 1(a) and 1(b) are cross-sectional views showing embodiments of the liquid crystal element of the present invention, respectively.

The liquid crystal element shown in FIG. 1(a) includes a pair of upper substrate 118 and lower substrate ttb arranged in parallel, and transparent electrodes 12a and 12b wired to each substrate. Upper substrate 11
A ferroelectric liquid crystal, preferably a non-helical ferroelectric liquid crystal 13 having at least two stable states, is disposed between the ferroelectric liquid crystal 8 and the lower substrate 11b.

The transparent electrodes 12a and 12b described above are ferroelectric
In order to perform multi-plexing [+] 3, it is preferable that the wires are wired in a stripe shape, and that the stripe shapes are arranged so as to intersect with each other.

In the liquid crystal element shown in FIG. 1(a), the substrates 118 and 11b
Orientation control films 14a and 14b formed of the aforementioned polyether resin or linear sulfur atom-containing polyolefin resin, respectively, are disposed on the substrates. At this time, the alignment control films 14a and 14b are formed with a film of polyether resin or polyolefin resin containing sulfur atoms in the direct daughter, but it is possible to have a function as an insulating film, and it is usually 50 to 1 μm.
It is formed to have a film thickness of approximately 100 m, preferably 100 to 2000, more preferably 500 to 2000.

Moreover, the alignment control film 1 used in the liquid crystal element shown in FIG. 1(a)
It is also possible to use one of 4a and 14b as a polyether resin or a straight sulfur-containing polyolefin resin, and use the other as an alignment control film other than the above-mentioned resin.

The orientation control film used at this time can be a film formed of polyimide, polyamide, or undenatured polyvinyl alcohol. Further, as shown in FIG. 1(b), in the present invention, the alignment control film 14 used in the liquid crystal element of FIG. 1(a)
It is also possible to omit the use of b.

In the present invention, a monoglazed orientation axis can be provided to the aforementioned orientation control films 14a and 14b. This uniaxial orientation axis can be imparted preferably by a rubbing process. At this time, the above-mentioned -axial arrangement coaxes can be parallel to each other, but it is also possible to make them intersect with each other.

Next, a ferroelectric liquid crystal having molecular alignment forming a plurality of layers perpendicular to the planes of a pair of parallel substrates used in the liquid crystal element of the present invention will be described.

FIG. 2 schematically depicts an example of a ferroelectric liquid crystal cell using a helical structure. 218 and 21b are I n2
03.5n02 and ITO (Indium Tin
A substrate (glass plate) coated with a transparent electrode such as SmC' (Oxide), between which a plurality of liquid crystal molecular layers 22 are oriented to form a layer perpendicular to the surface of the glass substrate.
(chiral smectic C phase) liquid crystal is sealed. A thick line 23 represents a liquid crystal molecule, and this liquid crystal molecule 23 has a dipole moment (P) 24 in a direction perpendicular to the molecule. At this time, the angle forming the apex angle of the triangular pyramid represents the tilt angle of 0 in the chiral smectic phase of the helical structure.

When a voltage higher than a certain threshold is applied between the electric fences on the substrates 218 and 21b, the helical structure of the liquid crystal molecules 23 is unraveled, and the dipole moment (on P) 24 becomes the same in the direction of the electric field. The orientation direction of 23 can be changed.

However, a ferroelectric liquid crystal using this helical structure returns to its original helical structure when no electric field is applied, and does not show any decline in bistability.

In preferred embodiments of the invention, at least 2
A ferroelectric liquid crystal element shown in FIG. 3 having two stable states, particularly a bistable state, can be used. That is, when the thickness of the liquid crystal cell is made sufficiently thin (for example, 1 μm),
As shown in Figure 3, even when no electric field is applied, the helical structure of the liquid crystal molecules unravels and becomes a non-helical structure, and the dipole moment Pa or pb is either upward (34a) or downward (34b). and a bistable state is formed.

When an electric field Ea or Eb of different polarity above a certain threshold is applied to such a cell as shown in FIG. 3, the dipole moment electric field Ea or Eb will move upward j; The liquid crystal molecules change direction accordingly, either in the first stable state 33a or in the second stable state 33a.
is oriented in one of the stable states 33b.

At this time, 1/2 of the angle formed by the first and second stable states corresponds to the tilt angle θ.

There are two advantages to using such a ferroelectric liquid crystal as an optical modulation element. Firstly, the response speed is extremely fast, and secondly, the alignment of liquid crystal molecules has bistability. The second point will be explained with reference to FIG. 3, for example. When the electric power Ea is applied, the liquid crystal molecules are oriented in the first stable state 33a, and this state remains stable even when the electric field is turned off. Further, when an electric field Eb in the opposite direction is applied, the liquid crystal molecules are oriented in a second stable state g, 33 b, and the orientation of the molecules is changed, 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 the memo IJ effect due to such fast response speed and bistability, it is preferable that the cell be as thin as possible;
~5 μm is suitable. A liquid crystal-electro-optical device having a matrix electrode structure using ferroelectric liquid crystals of this kind has been described, for example, by Clark and Lagauer in US Pat.
No. 67.924.

Examples of the ferroelectric liquid crystal that can be used in the liquid crystal element of the present invention include p-decyloxybenzylidene-p'-
Amino-2-methylbutylcinnamate (DOBAMB)
C), P-hexyloxybenzylidene-p'-amino-2-chloropropylcinnamate (HOBACPC)
, P-desyloxyhenzylidene-p'-amino-2-methylbutyl-α-cyanocinnamate (DOBAMBC
C), P-tetradecyloxybenzylidene-p'-amino-2-methylbutyl-α-cyanocinnamate (TD
OBAMBCC), 1-octyloxybenzylidene-p'-amino-2-methylbutyl-α-chlorocinnamate (OOBAMBCC), P-octyloxybenzylidene-p'-amino-2-methylbutyl-α-methylcinnamate, 4. 4'-Azoxycinnamic acitobis(2-methylbutyl) ester, 4-8-
(2-Methyl)butylresolcylidene-4'-octylalinine, 4-(2'-methylbutyl)phenyl-4'
-cutyloxybiphenyl-4-carboxylate,
4-hexyloxyphenyl-4-(2''-methylbutyl)biphenyl-4'-carboxylate, 4-hexyloxyphenyl-4-(2''-methylbutyl)biphenyl-4'-carboxylate, 4-hebutyl Phenyl-4-(4"-methylhexyl)biphenyl-4'-carboxylate, 4-(2"-methylbutyl)phenyl-4-(4"-methylhexyl)biphenyl-4'
-carboxylate, which can be used alone or in combination of two or more, and can contain other cholesteric liquid crystals or smectic liquid crystals as long as they exhibit ferroelectricity.

Further, in the present invention, a chiral smectic phase can be used as the ferroelectric liquid crystal, and specifically, chiral smectic C phase (SmC'), H phase (SmH''), I phase (Sml'')1. phase (SmK”) and phase G (SmG”)
) can be used.

FIG. 4 is a cross-sectional view schematically showing the uniform orientation state of a ferroelectric liquid crystal element when no voltage is applied;
The figure shows the optical response characteristics to the pulse signal at that time. That is, FIG. 4 is a cross-sectional view of the vertical layer 32 formed of a plurality of chiral smectic liquid crystal molecules shown in FIG. 3, viewed from the normal direction, and 41 in FIG. 33b onto the aforementioned vertical layer 32 (
42 represents the tip of the liquid crystal molecule 33a or 33b relative to the vertical layer 32 described above. Therefore, according to FIG. 4, the liquid crystal molecules in the vertical layer 32 are aligned substantially parallel to each other, and the tilt angle θ can be brought close to the maximum tilt angle O.

This state is called a uniform orientation state.

On the other hand, in FIG. 5, the vertical layer 32 is
This represents the arrangement state of liquid crystal molecules within the . As can be seen from FIG. 5, the tip portion 42 of the liquid crystal molecule 41 in the vertical layer 32
rotates along the circumference in the thickness direction of the vertical layer. Therefore, the liquid crystal molecules adjacent to the substrates 218 and 21b are not parallel to each other, and the liquid crystal molecules in the vertical layer 32 are oriented in a continuous twisted state from the substrates 218 to 21b. Become.

Such an orientation state is called a spray orientation state.

This spray orientation state assumes the uniform orientation state shown in FIG. 4 under a condition where a predetermined voltage is applied, but -
It was found that when the applied voltage was cut off and the memory state was established, the spray orientation state shown in FIG. 5 was returned to. Therefore,
In the spray alignment state, as shown in Figure 7, under voltage application, it exhibits high transmittance optical properties based on the uniform alignment state, but when no voltage is applied, the tilt angle θ returns to the original spray alignment state where the tilt angle θ is small. This causes the optical characteristics to have low transmittance.

On the other hand, in the uniform orientation state shown in FIG.
Since the above-mentioned spray orientation state is not adopted, the high transmittance characteristic when the voltage is applied can be maintained as is even under the memory state when the applied voltage is cut off, as shown in FIG.

That is, in Fig. 6, the voltage is 10 mm and the pulse width is 500 μs.
A transmittance curve 61 is shown when a pulse 62 of ec is applied, and it can be seen that the transmittance when the pulse is applied is maintained even under the memory state of a voltage of 0. FIG. 7 shows a transmittance curve 71 when a similar pulse 72 with a voltage of 10 V and a pulse width of 500 μsec is applied. According to the transmittance curve 71, the 'LA rate is high for pulse application, and this causes flickering during driving. Furthermore, under the memory state of voltage Ov, the transmittance decreases rapidly, which causes darkness on the display screen.

In a preferred embodiment of the present invention, pretreatment by application of an alternating current is effective for the ferroelectric liquid crystal to adopt the uniform alignment state shown in FIG. By this AC application pre-treatment, the above-mentioned tilt angle θ can be increased to an angle that is equal to or approximately the same as the tilt angle 2 in the spiral structure. The AC voltage used in this case is 20 to 500V.

Preferably 30-150V and frequency 10-500Hz,
Preferably, a frequency of 10 to 200 Hz can be used, and IA filling can be performed before applying the alternating current by applying the voltage for several seconds to about 10 minutes.

In addition, such alternating current application preprocessing is performed at a stage before writing is performed on the liquid crystal element in response to, for example, a video signal or an information signal, and is preferably performed to reduce the wait time when such a liquid crystal element is incorporated into a device and the device is operated. The above-mentioned alternating current application pretreatment can be performed, or alternatively, the alternating current application pretreatment can be performed even during the manufacture of such a liquid crystal element.

Such AC application pre-treatment can increase the tilt angle θ to the same extent as the tilt angle ■ in the helical structure before application, and even after removing the AC application, the tilt angle θ can be increased to the same extent as the tilt angle An increased tilt angle can be maintained.

In addition, such AC application pretreatment is performed on a ferroelectric liquid crystal with large spontaneous polarization (for example, 5 nc/cm 2 or more at 25° C., preferably 10 nc/cm 2 to 300 nc/cm 2 :n
c is a unit indicating nanocoulombs). This spontaneous polarization can be measured using a 100 μ cell using the triangular wave application method.

8 Japanese Journal of Applied Physics
f Applied Physias)22 (1
0), pp. 661-663 (1983), co-authored by K. Miyasato et al.
Direct Method Quiz Triangle
Waves for Measuring Subontanas
Bolarization in Felonic Liquid Crystal “(”Direct Metho
d with Triangular Waves
forMeasuring 5pontaneou
sPolarization in Ferr.

electric Liquid Cry 5t
al”).

(Example) Hereinafter, the present invention will be explained by giving specific examples and comparative examples.

Example 1 A liquid crystal element was produced using polyethylene oxide with a degree of polymerization of 90.000 as an alignment control film.

Two 0.7 mm thick glass plates were prepared, and an ITO film was formed on each glass plate.

An aqueous solution in which polyethylene oxide was dissolved at a ratio of 2% by weight was placed on each of the glass plates with the ITO film at a rotation speed of 2.
Coating was performed for 60 seconds using a 000r, p, m spinner. After the film was formed, a baking treatment was performed at 180° C. for about 1 hour. The thickness of the coating film at this time was about 200.

After firing, the film was rubbed with acetate flocked cloth, then washed with isopropyl alcohol solution, and alumina beads with an average particle size of about 1 μm were sprinkled on one glass plate. A cell was created by stacking two glass plates so that their processing axes were parallel to each other.

The cell thickness of this cell was measured using a Bereck phase plate (measurement based on phase difference) and was found to be approximately 1 μm. After injecting rCs-1011 (product name) manufactured by Chisso Corporation into this cell under vacuum, 0.5
Orientation could be achieved by slow cooling to 60'C at a rate of °C/h. Subsequent experiments were conducted at 60°C.

The phase change of rCS-1011J mentioned above was as follows.

56 °C 78 °C 94 °C (SmA
: Smectic A phase, Ch, cholesteric phase, Iso
When this cell was observed under crossed nicols, monodomains were obtained that formed a uniform, defect-free chiral smectic C phase with a non-helical structure.

Next, the above-mentioned liquid crystal cell was applied with a voltage of 70V and a frequency of 70H.
High electric field AC of z was applied for about 1 minute (AC application pre-treatment)
. When the tilt angle θ at this time was measured, it was 18°.

This tilt angle θ is determined by the pulse electric field (IOV, 5
By applying a pulse of and a pulsed electric field of opposite polarity (
By applying -10V, 500μ5ec),
After changing the state to the other stable molecular alignment state to create a bright state, measurement can be performed by rotating the liquid crystal cell again and finding the angle at which the darkest state occurs. The positions of these two darkest states correspond to the detection of a stable average molecular axis of the liquid crystal, and the angle between these two states corresponds to the tilt angle 2θ.

It was found that the liquid crystal cell of this example maintained a tilt angle of 18° over a period of one week or more.

Furthermore, when the liquid crystal element of this example was subjected to multiplex driving under the following driving conditions, a flickering-free display screen was formed.

Driving conditions (1) 1st step; Pulse width 500 μS for all scanning lines
eC, a signal with a voltage of 10 V, and a signal with a pulse width of 500 μsec and a voltage of -5 V are applied to all signal lines at once.

(2) Second step; pulse width 5 as scanning selection signal
This signal is sequentially applied to the scanning lines using a pulse width of 500 μsec and a voltage of 10 V, and a signal with a pulse width of 500 μsec and a voltage of 5 V and a signal with a pulse width of 500 μsec and a voltage of −5 V are selectively applied in synchronization with the scanning selection signal. Apply to the signal line.

Examples 2 to 5 Polyacetal (Example 2), polypentamethylene sulfone (Example 3), polyhexamethylene sulfone (Example 4), polyacetal that is a copolymer of ÷CH20-)- and +CH2CH20- Copolymer (Example 5)
A cell similar to that in Example 1 was prepared using the same method as in Example 1, and then AC application pretreatment was performed in the same manner as in Example 1.

The tilt angle θ at that time and the tilt angle θ after being left for one week were measured. These results are shown in Table 1.

A display screen was formed from each of these liquid crystal cells by multiplexing driving similar to that in Example 1, but there was no flicker during writing in any of them even one week after the AC application pretreatment.

Comparative Example 1 The polyethylene oxide resin used when creating the liquid crystal cell of Example 1 was replaced with polyimide resin (3,3', 4.4'
A film coated with a 3.5% by weight N-methyl-2-pyrrolidone solution of polyamic acid obtained by a dehydration condensation reaction of -diphenyltetracarboxylic anhydride and p-) unilene diamine at a molar ratio of 1:1. A liquid crystal cell was prepared in exactly the same manner as in Example 1, except that polyimide (formed by dehydration and ring closure) was used, and the same AC pretreatment as in Example 1 was performed.

The tilt angle θ of the liquid crystal cell at this time was measured and found to be 8°. Further, although a display screen was formed using this liquid crystal cell by multiplexing driving similar to that in Example 1, flickering occurred during writing.

Comparative Example 2 Except that the polyethylene oxide resin used when creating the liquid crystal cell of Example 1 was replaced with polyvinyl alcohol,
A liquid crystal cell was prepared in exactly the same manner as in Example 1, and the same pretreatment for application of alternating current as in Example 1 was performed.

When the tilt angle θ of the liquid crystal cell at this time was measured, it was found to be 17
．． It was 5°. Roughly measuring the maintenance time of the 18° tilt angle θ of this liquid crystal cell, the tilt angle decreased to 15.5° on the second day, and after one week, the tilt angle decreased to approximately 10°. It was found that it decreased by. Further, a display screen was formed on the liquid crystal cell after being left for one week by the same multi-plexing drive as in Example 1, but flickering occurred during writing.

(Effects of the Invention) According to the present invention, it is possible to realize a ferroelectric liquid crystal in a uniform alignment state that can obtain an increased tilt angle, and moreover, it is possible to stably maintain this uniform alignment state over a long period of time. can do.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are cross-sectional views showing embodiments of the liquid crystal device of the present invention, and FIG. 2 is a perspective view schematically showing a liquid crystal device using a ferroelectric liquid crystal with a spiral structure. Third
The figure is a perspective view schematically showing a liquid crystal element using a ferroelectric liquid crystal with a non-helical structure, Fig. 4 is a cross-sectional view schematically showing a uniform alignment state, and Fig. 5 is a schematic representation of a spray alignment state. A cross-sectional view, FIG. 6 is a characteristic diagram showing optical response characteristics in a uniform orientation state, and FIG. 7 is a characteristic diagram showing optical response characteristics in a splayed orientation state. 11 a -------------Top substrate 1 l b
- One lower substrate 12a, 12b - One transparent electrode 13 - One ferroelectric liquid crystal 14a,
14b - One alignment control film 218,'21b--Substrate 22-1------Liquid crystal molecule layer 23---
−−−−−−−−One liquid crystal molecule 24−−−−−−−−−
- One dipole moment 32 -------- One vertical layer 33 a ------- One - First stable state 33 b - One first 2 stable state 34
a −−−−−−−−−One upward dipole moment 34 b −−−−−−−−−One downward dipole moment Tilt angle θ -11 ------- Tilt angle E a, E b in non-helical structure -1 Electric field 4
1 ----------Projection of one liquid crystal molecule onto a vertical layer (C-brefter) 42 ---------------- Tip portion of a liquid crystal molecule relative to one vertical layer 61 - ------------- Transmittance curve 62, 72 in uniform orientation state -------- Pulse 71 ------- Transmittance curve 2 in spray orientation state Figure Tilt Ayao II Figure 4 Figure 5

Claims (21)

[Claims] (1) In a liquid crystal element comprising a pair of parallel substrates and a ferroelectric liquid crystal having a molecular arrangement forming a plurality of layers perpendicular to the planes of the pair of parallel substrates, the pair of parallel substrates A liquid crystal element, wherein at least one of the substrates has a coating of a polymer compound having a CH_2 chain and a heteroatom that preferentially orients the plurality of layers in one direction. (2) The liquid crystal element according to claim 1, wherein the hetero atom is an oxygen atom. (3) The liquid crystal element according to claim 1, wherein the hetero atom is a sulfur atom. (4) The liquid crystal element according to claim 1, wherein the CH_2 chain and the heteroatom are arranged in a straight chain. (5) The liquid crystal device according to claim 1, wherein the polymer compound is polyether. (6) The liquid crystal element according to claim 1, wherein the polymer compound is polyethylene oxide. (7) The liquid crystal element according to claim 1, wherein the polymer compound is polyacetal. (8) The liquid crystal device according to claim 1, wherein the polymer compound is a polyacetal copolymer. (9) The liquid crystal device according to claim 1, wherein the polymer compound is polytetramethylene sulfone. (10) The liquid crystal device according to claim 1, wherein the polymer compound is polypentamethylene sulfone. (11) The liquid crystal device according to claim 1, wherein the polymer compound is polypentamethylene thioether. (12) The liquid crystal device according to claim 1, wherein the polymer compound is polyhexamethylene sulfone. (13) The liquid crystal device according to claim 1, wherein the polymer compound is polyhexamethylene thioether. (14) The degree of polymerization of the polymer compound is 5000 to 500
000. The liquid crystal element according to claim 1, which is 000. (15) The degree of polymerization of the polymer compound is 1000 to 100
000. The liquid crystal element according to claim 1, which is 000. (16) The liquid crystal element according to claim 1, wherein the coating is a coating formed of a copolymer containing two or more types of polymer compounds having CH_2 chains and heteroatoms. (17) The liquid crystal element according to claim 1, wherein the coating has a uniaxial alignment axis. (18) The liquid crystal element according to claim 17, wherein the uniaxial alignment axis is an alignment axis imparted by a rubbing process. (19) The liquid crystal element according to claim 1, wherein the ferroelectric liquid crystal has a chiral smectic phase. (20) The liquid crystal element according to claim 1, wherein the ferroelectric liquid crystal is a liquid crystal that exhibits at least two stable alignment states in the absence of an electric field. (21) The liquid crystal element according to claim 1, wherein the ferroelectric liquid crystal is a chiral smectic liquid crystal with a non-helical structure and has a tilt angle of 18° or more.