JPH1152389A - Liquid crystal element and liquid crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal element having a large driving margin, excellent durability, high precision and high quality by forming an orientation controlling film on at least one of a pair of substrates and incorporating a polymer surfactant into at least one orientation controlling film. SOLUTION: A liquid crystal layer 1 comprising a liquid crystal compsn. is held between a pair of substrates 2a, 2b facing each other. Orientation controlling films 4a, 4b are formed on one or both of the substrates 2a, 2b, and at least one orientation controlling film of the orientation controlling films 4a, 4b contains a polymer surfactant as a component. As for the polymer surfactant, a cationic polymer surfactant is preferably used, and the mol.wt. of the polymer surfactant is preferably large to a certain degree or more, considering good binding property and non-bleeding property. Therefore, the weight average mol.wt. of the polymer is preferably >=1000. The polymer surfactant is introduced into the orientation controlling film by mixing into the film is formed. Especially, a polyimide can be especially preferably introduced since it has high controlling performance for uniaxial orientation.

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, and a liquid crystal device including a display device using the same.

[0002]

2. Description of the Related Art Conventionally, as a liquid crystal display element widely used, for example, M. Schad
t) and W. Helfrich
h) "Applied Physics Lette"
rs "Volume 18, Issue 4 (issued February 15, 1971)
One using a twisted nematic liquid crystal shown on pages 127 to 128 is known. Further, a simple matrix type liquid crystal element is known as a typical liquid crystal element. This type has an advantage in that the element can be easily formed and the cost is low.

However, in the case of time-division driving using a matrix electrode structure having a high pixel density, there is a problem that crosstalk occurs, so that the number of pixels has been limited. In addition, the response speed is as slow as 10 milliseconds or more, which limits the use as a display.

In recent years, a liquid crystal element called a TFT has been developed for such a simple matrix type element. In this type, since a transistor is formed for each pixel, problems of crosstalk and response speed are solved. On the other hand, it is very difficult to produce a liquid crystal element without defective pixels as the area becomes larger, and there is also a problem that even if possible, a large cost is generated.

In order to improve the disadvantages of the conventional liquid crystal device, a device using a liquid crystal exhibiting bistability has been proposed by Clark and Lagerw.
a11) (JP-A-56-1072).
No. 16, US Pat. No. 4,367,924). Generally, a ferroelectric liquid crystal composed of a chiral smectic C phase is used as the liquid crystal exhibiting the bistability. Since the ferroelectric liquid crystal performs inversion switching by spontaneous polarization, a very fast response speed can be obtained and a bistable state having a memory property can be developed. Further, since the viewing angle characteristics are also excellent, it is considered that they are suitable as a high-speed, high-definition, large-area display element or a light valve.

[0006]

In the liquid crystal element, the driving voltage of all or some of the pixels may be reduced, or the switching behavior may be abnormally or locally, even if not reduced. In addition, even when there is no such abnormality at the beginning of the element production, the deterioration of the switching and the change of the threshold voltage occur with time. These phenomena significantly impair the display quality and quality of the liquid crystal element, and have a great influence on the productivity.

In particular, in a display element using a ferroelectric liquid crystal, the N COM electrodes for giving a selection signal and the M SEG electrodes for giving a write signal are formed in a simple matrix system which is orthogonal to each other. It becomes an element superior in cost. In general, the switching speed of the ferroelectric liquid crystal is two or three digits faster than that of the TN liquid crystal or the like. ing. As a promising method of the improvement, spontaneous polarization (Ps [nC / cm ² ]) may be increased.
The reason is that from the switching model, the speed is
This is because it is proportional to Ps · E / η (Ps: spontaneous polarization, E: electric field, η: viscosity coefficient).

However, this spontaneous polarization (Ps [nC
/ Cm ² ]) causes various problems when actually driven as a liquid crystal display element.
For one thing, there is the problem of "anti-electric field". Due to the large spontaneous polarization, electric charges are accumulated in the insulating film and the orientation control film, and when the external electric field for writing is removed, the ferroelectric liquid crystal is inverted by the internal `` reverse electric field '' created by the accumulated electric charges, The memory effect decreases. This phenomenon is more conspicuous as the spontaneous polarization increases, and contradicts the demand for improving the response speed. Due to the presence of this internal "reverse electric field", in an actual display element, the display quality is remarkably deteriorated due to the generation of inversion domains and the fluctuation of liquid crystal molecules due to the information signal. There was a problem. Conventionally, as a solution to the above phenomenon, a method of adding an impurity to the liquid crystal to cancel the internal electric field,
A method of canceling “internal electric field” through an external circuit using an orientation control film having high conductivity (“Jpn. J. App. Ph.
ys. ", 28 (1989) L116, Nakaya
et al) have been proposed.

The large polarization of the liquid crystal tends to attract ionic or polar impurities, and the liquid crystal having the large polarization tends to be mixed with ionic or polar impurities depending on the materials constituting the device and various manufacturing conditions. have. Many of these ionic or polar impurities have an adverse effect on drive characteristics such as abnormal switching or deterioration unless used in a controlled manner, which is a major problem when using a liquid crystal with a large polarization. This is a problem that exists not only in the initial stage of device fabrication but also in terms of long-term drive deterioration with a long relaxation time.

The present invention has been made in order to solve such problems of the prior art, and has a large driving margin, excellent durability, a high-definition, high-quality liquid crystal element, and the liquid crystal element. It is an object of the present invention to provide a liquid crystal device using the same.

[0011]

That is, the present invention provides a liquid crystal device 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,
At least one of the alignment control films is a liquid crystal element containing a polymer surfactant.

Further, the present invention is a liquid crystal device having at least the above-mentioned liquid crystal element and means for driving the liquid crystal element.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive studies, the present inventors have obtained a liquid crystal device in which a liquid crystal composition is sandwiched between a pair of substrates, and at least one of the pair of substrates has an alignment control film. In addition, the above problem has been solved by a liquid crystal element in which at least one of the alignment control films contains a polymer surfactant.

Specifically, a first aspect of the present invention is to provide a liquid crystal device having a liquid crystal composition sandwiched between a pair of substrates opposed to each other, wherein an alignment control film is provided on one or both of the substrates. A liquid crystal device characterized in that at least one of the alignment control films contains a polymer surfactant as one component.

A second aspect of the present invention is characterized in that, in a liquid crystal device containing a polymer surfactant in an alignment control film, after the liquid crystal cell is overheat-treated in a high humidity atmosphere, a liquid crystal composition is injected. Liquid crystal element. A third aspect of the present invention is a display device including the above-described liquid crystal element and a unit for driving the liquid crystal element.

Hereinafter, an example of the structure of the liquid crystal element of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an example of the chiral smectic liquid crystal device of the present invention. In the figure, reference numeral 1 denotes a liquid crystal layer made of a chiral smectic liquid crystal composition. When a chiral smectic liquid crystal is used as the liquid crystal, the layer thickness is usually 5 μm in order to realize bistability.
The following is preferred. 2a and 2b are substrates, made of glass, plastic or the like. 3a and 3b are transparent electrodes such as ITO. Reference numerals 4a and 4b denote alignment control films, which require a uniaxial alignment control film in which a uniaxial alignment process is performed on at least one substrate. As a method of forming the uniaxial orientation control film,
For example, inorganic substances such as silicon monoxide, silicon dioxide, aluminum oxide, zirconia, magnesium fluoride, cerium oxide, cerium fluoride, silicon nitride, silicon carbide, boron nitride, etc. by solution coating or vapor deposition or sputtering on a substrate And organic materials such as polyvinyl alcohol, polyimide, polyimide amide, polyester, polyamide, polyester imide, polyparaxylene, polycarbonate, polyvinyl acetal, polyvinyl chloride, polystyrene, polysiloxane, cellulose resin, melamine resin, urea resin, and acrylic resin. After forming a film by rubbing, the surface is rubbed with a fibrous material such as velvet, cloth or paper. Also, an oblique deposition method of depositing an oxide or a nitride of SiO or the like from an oblique direction of the substrate may be used. These materials and forming methods can be used without imparting uniaxial orientation such as rubbing on one substrate side.

In particular, the liquid crystal element of the present invention is a liquid crystal element in which a chiral smectic liquid crystal composition showing at least two stable states is sandwiched between a pair of substrates, and one of the pair of substrates is uniaxial. An orientation control film that has been subjected to an orientation process is provided, and an orientation control film that has not been subjected to a uniaxial orientation process is provided on the other substrate, and the orientation control film that has been subjected to the uniaxial orientation process is a polyimide. And a liquid crystal element in which the alignment control film not subjected to the uniaxial alignment treatment is made of a silane coupling agent or polysiloxane.

The thickness of the orientation control film is preferably 200 ° or less from the viewpoint of suppressing the magnitude of the reversal electric field generated with the switching of the spontaneous polarization Ps and having good switching performance. When it is less than 100 °, it may be more preferable.

In addition to the orientation control film, an insulating layer or another organic or inorganic layer may be formed as a short-circuit preventing layer for a pair of substrates. Reference numeral 5 denotes a gap control spacer, for example, silica beads or the like is used.
8a and 8b are polarizing plates, 5 is a sealing material, and 9 is a light source.

In the present invention, depending on the liquid crystal material used,
An element having an asymmetric alignment control film configuration, that is, an element having different orientation treatments on the respective substrates, that is, upper and lower substrates, is often used. In particular, when selecting a material having no cholesteric phase, an asymmetric alignment control film configuration that is easy to realize good uniform alignment, for example, an asymmetric configuration having an alignment control film subjected to uniaxial alignment processing only on one substrate is used. Used. Also, when using a liquid crystal material having a large spontaneous polarization,
In order to reduce the switching failure due to the anti-electric field, a non-uniaxial alignment control film having conductivity in the cell thickness direction is often used as the one-side alignment control film. As the alignment control film having conductivity in the cell thickness direction, for example, a film in which metal oxide fine particles and the like are dispersed in a binder base material is used.

The liquid crystal device of the present invention is characterized in that an alignment control film containing a polymer surfactant is used. By using an alignment control film containing a polymer surfactant, the present inventors have avoided switching abnormalities on the entire surface or a part of the liquid crystal element, and also realized the stability over time of the switching. I found what I could do. The mechanism is considered to be inactivated or immobilized by physically adsorbing or chemically adsorbing ionic or polar impurities that induce drive deterioration by ion exchange or the like. Therefore, for example, if drive deterioration is caused by organic cation-based impurities, it can be inactivated by using an anionic polymer surfactant.

The second is to increase the conductivity of the interface of the orientation control film containing a polymer surfactant and to leak and diffuse a non-localized electric field or charge which is a cause of drive deterioration. A major feature of the polymer surfactant is that, since it is a polymer, the binding property in the alignment control film is significantly superior to other surfactants. this is,
This means that the substance that acts on the drive deterioration does not bleed into the liquid crystal over time, and that the action has permanent properties. This is a great effect and feature in view of productivity.

The polymer surfactant used in the present invention depends on the type, structure, and material of the liquid crystal element. 1) The ionic or polar impurities that induce drive deterioration are different. 2) The resistance to the alignment control film is reduced. Request degrees are different,
Basically, it is preferable to use a polymer surfactant suitable for each liquid crystal element. However, in many liquid crystal elements, organic cations are often a problem, and anionic polymer surfactants are often used.
Also, considering good binding and non-bleeding properties,
It is preferable that the molecular weight of the high molecular surfactant is larger than a certain level, and the weight average molecular weight is preferably 1000 or higher,
It is more preferably 10,000 or more, and more preferably 30,000 or more.

The method of introducing the polymer surfactant into the orientation control film is carried out by mixing it into the orientation control film. In the case where the upper and lower alignment control films have different alignment treatments, they can be introduced into both or any one side. As the material of the orientation control film on the side containing the polymer surfactant, a material having a high adsorption activity is preferable from the viewpoint of binding property and non-bleeding property. In particular, polyimide can be particularly preferably introduced because it also has a high uniaxial alignment control ability.

In the present invention, from the viewpoint of enhancing the action and effect of the polymer surfactant, in a liquid crystal device containing the polymer surfactant in the alignment control film, water molecules are added to the alignment control film. Adsorption is sometimes effective.

As a method for adsorbing water molecules, before injecting the liquid crystal material into the empty cells, the water molecules are attached to the alignment control film inside the empty cells. Specifically, it is desirable to introduce a gas containing water molecules into the empty cell after degassing the empty cell by, for example, heating and reducing the pressure.

Next, examples of the polymeric surfactant used in the present invention include the following, but the present invention is not limited thereto. Polycarboxylate or anionic polymer surfactant Kao Corporation: Demol P, Demol EP, Demol S
T, Poise 521, Poise 530, Poise 532A manufactured by Aldrich: polyethylene-sodium methacrylate copolymer

Polyammonium salt or cationic polymer surfactant Kao Corporation: Softex K-160, Softex K-190, Softex K-370 Yoshimura Yuka Co., Ltd .: Permax S , Erik PS-5
0, Eliq PS-506 manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Rheox AS-70, Rheox AS-170 Nonionic polymer surfactant Aldrich: Polyethylene oxide

Next, the content of the polymer surfactant contained in the orientation control film in the present invention is usually 0.001 wt.
% To 30 wt%, preferably 0.005 to 20 wt%.

FIG. 8 is a schematic explanatory view showing a method for measuring the flow rate of ions in the liquid crystal element. The amount of charge Qt of ions flowing with respect to the electric field in the liquid crystal element is determined, for example, by applying a triangular wave voltage V _ex to the circuit shown in FIG. And the amount of current flowing in the liquid crystal is measured according to the positive and negative electric fields.
Is a portion other than the current peak due to the inversion of. At this time, the asymmetry of the charge amount of the flowing ions means the asymmetry of the peak shape and the asymmetry of the peak intensity. In normal measurement, the integrated values of the peaks are compared. In addition, the electric field intensity used for the normal measurement is 0. IV / μm to 50V / μ
m, the frequency is in the range of 0.0001 Hz to 1000 Hz.

Next, the chiral smectic liquid crystal composition having a chiral smectic phase used in the present invention will be described. The liquid crystal composition exhibiting a chiral smectic phase is preferably a liquid crystal composition exhibiting no cholesteric phase and a liquid crystal composition exhibiting ferroelectricity.
In particular, rubbing the surface of at least one of the substrates is particularly effective for a liquid crystal element having a so-called bookshelf alignment in which the obtained liquid crystal element has a layer inclination angle of 8 ° or less and does not refract a smectic phase.

The chiral smectic liquid crystal composition used in the present invention has no cholesteric phase,
And chiral smectic C from smectic A phase
The layer interval (d _A ) at the first transition point where the layer interval starts to decrease near the temperature at which the phase shifts, and the layer interval (d _A ) at which the layer interval decreases with the temperature drop from the first transition point and starts to increase again. 2
The relationship with the minimum value (d _min ) of the layer interval at the transition point of

[0033]

## EQU1 ## _A liquid crystal composition satisfying 0.990 ≦ d _min / d _A is used. By using the chiral smectic liquid crystal composition, a structure having a bookshelf or a layer close to it and having a small layer tilt angle can be exhibited. . As a specific example of this chiral smectic liquid crystal composition, for example, “Next-generation liquid crystal display and liquid crystal material” (edited by CMC Corporation and Atsuo Fukuda, 1992)
Year)).

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

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 r
b is independently 1 to 20; pa is 0 to 4; ), _{^{Or, -D 2 - (C xb F}} 2xb -O) za -C ya F
A group represented by _{2ya + 1} , wherein xb is independently 1 to 10 for each (C _xb F _2xb -O);
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-
Selected from} N (C _pb H _{2pb + 1} ) —CO— and a single bond;
And rd are 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.

[0037]

Embedded image In the formula, A ¹ , A ² and A ³ are each independently:

[0038]

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). L ¹ and L ² are each independently a single bond, —CO—O
-, -O-CO-, -COS-, -S-CO-, -CO
-Se-, -Se-CO-, -CO-Te-, -Te-
_{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- (C
H ₂ ) _ra -O- (CH ₂ ) _rb -,-(CH ₂ ) _ra -N (C
_pa H _{2pa + 1} ) -SO _{2- or-} (CH ₂ ) _ra -N (C _{pa
H2pa + 1} ) -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 is C
_xa F _2xa -X (X represents -H or -F, x
a is an integer of 1 to 20).

[0042]

Embedded image Wherein A ⁴ , A ⁵ and A ⁶ are each independently

[0043]

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, -C
O-O-, -O-CO-, -CO-S-, -S-CO
-, -CO-Se-, -Se-CO-, -CO-Te
-, - Te-CO -, - (CH 2 CH 2) ka - (ka is 1
To 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, -OC
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} (where xb is independently 1 to 10 for each (C _xb F _2xb -O)
And ya is 1 to 10, and za is 1 to 10.)

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

[0049]

Embedded image

[0050]

Embedded image

[0051]

Embedded image

[0052]

Embedded image

[0053]

Embedded image

[0054]

Embedded image

[0055]

Embedded image

[0056]

Embedded image

[0057]

Embedded image

[0058]

Embedded image

[0059]

Embedded image

[0060]

Embedded image

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.

[0062]

Embedded image

[0063]

Embedded image

[0064]

Embedded image

[0065]

Embedded image

[0066]

Embedded image

In the present invention, in particular, the chiral smectic liquid crystal composition is preferably a liquid crystal composition containing at least 50% by weight of a fluorine-containing liquid crystal compound containing at least one ether oxygen in the chain in the terminal portion of the fluorocarbon.

Further, specific examples of the optically active liquid crystalline compound as other constituents include those having the following structures, but the present invention is not limited thereto.

化合物 A compound represented by the following general formula (III).

[0070]

Embedded image

[0071]

[Table 1]

[0072]

[Table 2]

[0073]

[Table 3]

[0074]

[Table 4]

[0075]

[Table 5]

The abbreviations used in the specific examples of the compounds of the above formula (III) are as follows.

[0077]

Embedded image

[0078]

Embedded image

化合物 A compound represented by the following general formula (IV).

[0080]

Embedded image

[0081]

[Table 6]

[0082]

[Table 7]

[0083]

[Table 8]

[0084]

[Table 9]

[0085]

[Table 10]

The abbreviations used in the specific examples of the compound of the general formula (IV) are as follows.

[0087]

Embedded image

[0088]

Embedded image

[0089]

Embedded image

[0090]

Embedded image

[0091]

Embedded image

[0092]

Embedded image

N = 6,2R, 5R n = 6,2S, 5R n = 4,2R, 5R n = 4,2S, 5R n = 3,2R, 5R n = 2,2R, 5R n = 2,2S , 5R n = 1,2R, 5R n = 1,2S, 5R

[0094]

Embedded image

N = 1 n = 2 n = 3 n = 4 n = 6 n = 10

[0096]

Embedded image

N = 8 n = 10

[0098]

Embedded image

[0099]

Embedded image

[0100]

Embedded image

[0101]

Embedded image

[0102]

Embedded image

[0103]

Embedded image

It is preferable that the liquid crystal composition exhibiting a chiral smectic phase has a spontaneous polarization of 20 nC / cm ² or more.

As described above, the liquid crystal element of the present invention performs switching in response to a switching signal from a signal power supply (not shown), and functions as a light valve of a display element. Further, if the transparent electrodes on the substrate are vertically arranged in a cross matrix, pattern display and pattern exposure become possible, and for example, they are used as displays for personal computers and workstations, and as light valves for printers and the like.

The liquid crystal device of the present invention constitutes a liquid crystal device having various functions. The most suitable example is the case where the liquid crystal device is used for a display panel and the scanning line address shown in FIGS. 2 and 3 is used. The liquid crystal display device is realized by using a data format including image information having information and a communication synchronization unit using a SYN signal.

The reference numerals in the figure are as follows. Reference Signs List 101 Chiral smectic liquid crystal display device 102 Graphic controller 103 Display panel 104 Scan line drive circuit 105 Information line drive circuit 106 Decoder 107 Scan line signal generation circuit 108 Shift register 109 Line memory 110 Information signal generation circuit 111 Drive control circuit 112 GCPU 113 Host CPU 114 VRAM

The image information is generated by the graphic controller 102 of the main unit, and is transferred to the display panel 103 according to the signal transmission means shown in FIGS. The graphic controller 102 includes a CPU (central processing unit, abbreviated as GCPU 112) and a VRAM.
(Image information storage memory) Host CPU 1 with 114 as a core
13 manages image information and communicates with the liquid crystal display device 101. Note that a light source is disposed on the back surface of the display panel.

In the display device of the present invention, since the liquid crystal element as the display medium has good switching characteristics as described above, it exhibits excellent driving characteristics and reliability, and has high definition.
A high-speed, large-area display image can be obtained.

As a method of driving a chiral smectic liquid crystal element which is an example of the liquid crystal element of the present invention, for example, JP-A-59-193426 and JP-A-59-19342.
7, JP-A-60-156046, JP-A-60-156046
The driving method disclosed in Japanese Patent Application No. 0-156047 can be applied.

FIG. 6 is a diagram showing an example of a waveform diagram of the driving method. FIG. 5 is a plan view showing an example of a ferroelectric liquid crystal panel in which matrix electrodes are arranged. The liquid crystal panel 51 of FIG. 5 includes the scanning lines of the scanning electrode group 52 and the information electrode group 5.
And three data lines intersecting each other, and a ferroelectric liquid crystal is arranged between the scanning line and the data line at the intersection.

[0112] The S _S is selected scan waveform applied to the selected scanning line in FIG. 6 (A), the non-selection scanning waveform S _N is not selected, I _S is applied to the selected data line The selected information waveform (black), and _IN indicates a non-selected information signal (white) applied to an unselected data line. Also,
In Figure at _{(I S} -S S) and _(I N -S _S) is the voltage waveform applied to pixels on a selected scanning line, the voltage _(I S _-S S)
The pixel to which is applied a black display state, and the voltage ( _IN −
The pixel to which _{S s} ) is applied becomes a white display state.

FIG. 6B shows the driving waveform shown in FIG. 6A, which is a time-series waveform when the display shown in FIG. 4 is performed. In the driving example shown in FIG. 6, the minimum application time of a single polarity voltage Δt corresponds to the time the write phase t ₂ applied to a pixel on a selected scanning line, one line clearing phase t ₁ time 2
It is set to Δt. Now, the values of the parameters V _S , V _R , and Δt of the drive waveform shown in FIG. 6 are determined by the switching characteristics of the liquid crystal material used.

FIG. 7 shows the transmittance T when the drive voltage (V _S + V _I ) is changed while the bias ratio described later is kept constant.
, Ie, the VT characteristic. Here, Δt = 50 μsec, and the bias ratio V _I / (V _I + V
_S ) is fixed at 1/3. The positive side of Fig. 7 is shown in FIG. 6 _(I N _-S S), the negative side _{(I S} -S S) at the indicated waveform when applied _(V S + V _I) final transmission The relationship between the rates is shown.

Here, V ₁ and V ₃ are called an actual driving threshold voltage and a crosstalk voltage, respectively. Also, V ₂ <V ₁ <
When V _3, and referred to, is an important parameter of the matrix drivable voltage range _{(V 3 -V 1) / (} V 3 + V 1) voltage variable margin ([Delta] V).

[0116] V ₃ is a ferroelectric liquid crystal display element drive on, it may be said that generally present. Specifically, FIG.
A voltage value causing switching by _{V B} in _N -S _S) of the waveform. Of course, by increasing the bias ratio, it is possible to increase the value of V _3, increasing the bias ratio corresponds to a large amplitude of a data signal, an increase in flickering in image quality, This leads to a decrease in contrast, which is not preferable.

The present inventors have examined that the bias ratio is 1/3 to
About 1/4 was appropriate. By the way, if the bias ratio is fixed, the voltage margin ΔV strongly depends on the switching characteristics of the liquid crystal material and the element configuration, and it goes without saying that an element having a large ΔV is very advantageous for matrix driving.

Similarly, when the drive voltage is fixed and the voltage application time Δt is changed, the voltage application time threshold is set to Δt ₁ , the voltage application time crosstalk value is set to Δt ₂ , and (Δt ₂ −Δt ₁ ) / (Δt ₂ + Δt ₁ ) is defined as a voltage application time margin.

At a certain temperature, it is possible to write two states, black and white, on the selected pixel according to the two directions of the information signal, and the non-selected pixels maintain the black or white state. The voltage margin or voltage application time margin that can be obtained differs depending on the liquid crystal material and the element configuration, and is unique. In addition, since the drive margins are different depending on the change in the environmental temperature, in the case of an actual display device, it is necessary to set optimal drive conditions for the liquid crystal material, the element configuration, and the environmental temperature.

[0120]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to the following examples.
The liquid crystal composition used in this example is shown below.

[0121]

Embedded image

[0122]

Embedded image

The physical properties of the liquid crystal composition N are shown below.

[0124]

(Equation 2)

[0125]

[Table 11]

[0126]

Embedded image

The physical properties of the liquid crystal composition O are shown below.

[0128]

(Equation 3)

The following liquid crystal cells were prepared. (Liquid crystal cell Y) On one glass substrate with ITO, Toray Industries: Polyimide precursor LP64 and Kao Corporation: Polymer surfactant Poise 521 (solid content 0.5 wt%)
Was spin-coated with a solution of N-methylpyrrolidone (NMP) / n-butyl cellosolve (nBC) = 2/1, baked to obtain a polyimide, and then subjected to a rubbing treatment. The other glass substrate with ITO was spin-coated with a silane coupling agent (octadecyltriethoxysilane) and heat-treated.

[0130] A silica bead spacer was sprayed on one substrate, and the other substrate was bonded using an adhesive sealant (Chisso Corporation, Rixon Bond) to produce a cell. The cell gap is about 2 μm. Kao Poise 521 GP
The weight average molecular weight by C was 3000 or more.

(Liquid Crystal Cell Z) An alignment control film was formed on the first substrate of a pair of ITO glass substrates by the following method. After spin-coating a solution in which a polyimide precursor having the following repeating unit is dissolved in a 2: 1 solvent of N-methylpyrrolidone (NMP) and n-butylcellosolve (nBC) so as to be 0.5 wt%, baking is performed. Thus, an orientation control film was formed. A rubbing treatment was performed on the orientation control film thus formed.

[0132]

Embedded image

The second substrate was prepared by dissolving an ultrafine SnOx oxide particle (average particle diameter: 100 °) in a ladder-type polysiloxane base material in an ethanol solution having a solid concentration of 10 wt%, and adding it to Yoshimura Yuka Co., Ltd. ): A solution in which 3 wt% of a polymer surfactant Permax S (weight average molecular weight 5000) was added was applied to a film thickness of 2000 ° by spin coating. Then, after pre-drying at 80 ° C for 5 minutes,
Heat drying was performed at 100 ° C. for 3 hours. Silica beads having an average particle size of 2.0 μm were scattered on the first substrate, and the other second substrate was overlaid and bonded using an adhesive to produce a cell.

Example 1 A liquid crystal composition N was prepared in the cell Y manufactured by the method described above.
And the liquid crystal composition N was injected into the cell Z, and the liquid crystal composition O was injected into the cell Y, to produce liquid crystal elements β, γ and δ. For these resulting device, ion amount, and measurement of the margin (bias ratio is 1 / _{3.4, V} I +
V _S is 20V) was carried out.

Measurement of Ion Amount (Qt) The amount of ions was measured by applying a triangular wave voltage to the circuit shown in FIG. 8 and monitoring the voltage across a resistor connected in series to the liquid crystal element to monitor the current flowing in the liquid crystal. Measure the quantity,
The ion amount (Qt) is calculated by integrating the portion of the observed current peak other than the current peak (Ps) accompanying the reversal of spontaneous polarization.
Was calculated. Measurement temperature is 30 ° C, ± 20V, 5Hz
Was used. Table 1 shows the measurement results of the ion amount (Qt).
It is shown in FIG.

Measurement of Margin The margin was measured using a simple matrix waveform shown in FIG. The measurement temperature is 30 ° C and the drive voltage is 20
V, and the drive margin was measured by changing the pulse width. Table 12 shows the measurement results of the margin.

[0137]

[Table 12] As can be seen from the above results, the amount of ions is small and the change with time is extremely small. Further, the driving margin is very good, and the change with time is extremely small.

Example 2 For the liquid crystal elements β and γ in Example 1, a step of exposing the cell to a 90% humidity environment for 5 hours before injecting the liquid crystal and adsorbing water on the surface of the alignment control film was introduced. Created. The same effects as in Example 1 were obtained for those cells. In particular, the liquid crystal element γ had a very high durability with a margin retention rate after aging of 90% or more.

Example 3 In the liquid crystal element β in Example 1, instead of the step of applying a polyimide precursor containing a polymer surfactant,
In the step of applying the polyimide precursor, 10 wt% of polyethylene oxide (manufactured by Aldrich, weight average molecular weight of about 300,000) was introduced with respect to the polyimide, and a cell was prepared and evaluated in the same manner as in Example 1. A good effect was confirmed.

Comparative Example 1 A cell was prepared in the liquid crystal cell Y used in Example 1, except for the step of applying a polymer surfactant. The liquid crystal composition N was injected into this, and the same evaluation as in Example 1 was performed.
Twenty hours later, a twist orientation was observed in part, and the uniform orientation was not obtained. In addition, the liquid crystal composition O was similarly compared, and compared with the liquid crystal composition N,
Although the twisted area was reduced by half, the twist appeared again and the orientation was not completely uniform.

[0141]

As described in detail above, according to the present invention,
A liquid crystal element having a large driving margin and excellent durability can be realized, and a high definition and high quality liquid crystal element and a liquid crystal device using the liquid crystal element are provided.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one example of a chiral smectic liquid crystal device of the present invention.

FIG. 2 is a block diagram showing a display device provided with a liquid crystal element using the chiral smectic liquid crystal composition of the present invention and a graphic controller.

FIG. 3 is a diagram showing a timing chart of image information communication between a display device and a graphic controller.

FIG. 4 is a schematic diagram of a display pattern when actual driving is performed with the time-series driving waveform shown in FIG.

FIG. 5 is a plan view of an example of a ferroelectric liquid crystal panel on which matrix electrodes are arranged.

FIG. 6 is an example of a waveform diagram of a driving method used in the present invention.

FIG. 7 is a graph (VT characteristic diagram) showing a change in transmittance when a drive voltage is changed according to the present invention.

FIG. 8 is a schematic explanatory view showing a method for measuring the flow rate of ions in a liquid crystal element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Liquid crystal layer using chiral smectic liquid crystal composition 2a, 2b Substrate 3a, 3b Transparent electrode 4a, 4b Alignment control film 8a, 8b Polarizer 5 Sealing material 9 Light source I ₀ Incident light I Transmitted light 51 Liquid crystal panel 52 Scanning electrode group 53 Information electrode group 101 Chiral smectic liquid crystal display device 102 Graphic controller 103 Display panel 104 Scan line drive circuit 105 Information line drive circuit 106 Decoder 107 Scan signal generation circuit 108 Shift register 109 Line memory 110 Information signal generation circuit 111 Drive control circuit 112 GCPU 113 Host CPU 114 VRAM

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G02F 1/133 560 G02F 1/133 560 1/141 G09F 9/35 303 G09F 9/35 303 G02F 1/137 510 (72) Invention Person: Sho Makoto Mori 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shuji Yamada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Koji Noguchi: Inventor 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masahiro Terada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yasushi Asao Ota-ku, Tokyo 3-30-2 Shimomaruko Canon Inc.

Claims (16)

[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, and at least one of the alignment control films is a polymer interface. A liquid crystal device comprising an activator. 2. The liquid crystal device according to claim 1, wherein the polymer surfactant has a weight average molecular weight of 1,000 or more. 3. The liquid crystal device according to claim 1, wherein the polymer surfactant is an anionic polymer surfactant. 4. The liquid crystal device according to claim 1, wherein the alignment control film containing the polymer surfactant is polyimide. 5. The liquid crystal device according to claim 1, wherein an alignment control film is provided on the pair of substrates, and the alignment control films are subjected to different alignment treatments. 6. The liquid crystal device according to claim 1, wherein water molecules are adsorbed on the alignment control film containing the polymer surfactant. 7. The liquid crystal device according to claim 1, wherein the liquid crystal composition is a liquid crystal composition exhibiting a chiral smectic phase. 8. The liquid crystal device according to claim 7, wherein the liquid crystal composition does not exhibit a cholesteric phase. 9. The liquid crystal device according to claim 1, wherein the liquid crystal composition is a liquid crystal composition exhibiting ferroelectricity. 10. The liquid crystal device according to claim 7, wherein the liquid crystal composition exhibiting a chiral smectic phase has a spontaneous polarization of 20 nC / cm ² or more. 11. A fluorine-containing liquid crystal compound having a terminal portion of a fluorocarbon and a terminal portion of a hydrocarbon, wherein both terminal portions are bound by a central nucleus, and having a smectic intermediate phase or a potential smectic intermediate phase. The liquid crystal device according to claim 1, further comprising: 12. The liquid crystal device according to claim 11, wherein the terminal portion of the fluorocarbon in the fluorine-containing liquid crystal compound is a group represented by -D ¹ -C _xa F _2xa -X. (However,
The formula xa is 1 to 20, X represents -H or -F, D ¹ _{is, -CO-O- (CH 2)} ra -, - O- (C
_{H 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 to 20, and pa is 0 to 4. ) 13. fluorocarbon terminal portion in the fluorine-containing liquid crystal _{^{compounds, -D 2 - (C xb F}} 2xb -O)
_za -C _ya F _{2ya + 1} liquid crystal device according to claim 11, wherein a group represented by. (Where xb in the above formula is (C _xb
F _2xb -O) independently represents 1 to 10, and ya represents 1 to 10
And 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
_{H2pb + 1} ) -CO-, a single bond, rc and rd
Is independently 1-20, and sa is the respective (C _sa H
_2sa- O) is independently 1 to 10, ta is 1 to 6, and pb is 0 to 4. ) 14. The liquid crystal device according to claim 11, wherein the fluorine-containing liquid crystal compound is represented by the following general formula (I). Embedded image Wherein A ¹ , A ² , and A ³ are each independently: Represents ga, ha, and ia each independently represent an integer of 0 to 3 (provided that ga + ha + ia is at least 2). Each L ¹ and L ² is independently a single bond, —CO—O—,
-O-CO-, -COS-, -S-CO-, -CO-S
e-, -Se-CO-, -CO-Te-, -Te-CO
_{-, - CH 2 CH 2 -} , - CH = CH -, - C≡C -, -
CH = N -, - N = CH -, - CH 2 -O -, - O-C
Represents H ₂ —, —CO— or —O—. Each X ¹ ,
Y ¹ and Z ¹ are substituents of A ¹ , A ² and A ³ , and independently
H, -Cl, -F, -Br, -I, -OH, -OC
Represents H ₃ , —CH ₃ , —CN, or —NO ₂ , and each of ja, ma, and na independently represents an integer of 0 to 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} ) —C
Represents O-. ra and rb are independently 1-20, and pa is 0-4. R ¹ is _{-OC qa} H _2qa -O
-C _qb H _{2qb + 1} , -C _qa H _{2qa -OC qb} H _{2qb + 1} , -C
_qa H _2qa -R ³ , _{-OC qa} H _2qa -R ³ , -CO- _OC
qa H _2qa -R ^3, or represents _{-O-CO-C qa H 2qa} -R 3, linear, may be either branched (Here, R
_{^3, -O-CO-C qb H} 2qb + 1, -CO-O-C qb H
_{2qb + 1, -H, -Cl,} -F, -CF 3, -NO 2, -C
N, and qa and qb are independently 1-20).
R ² represents a C _xa F _2xa -X (X represents -H or -F, xa is an integer of 1 to 20). ] 15. The liquid crystal device according to claim 11, wherein the fluorine-containing liquid crystal compound is represented by the following general formula (II). Embedded image Wherein A ⁴ , A ⁵ , and A ⁶ are each independently: Represents gb, hb, and ib are each independently an integer of 0 to 3 (however, gb + hb + ib is at least 2)
Represents L ³ and L ⁴ are each independently a single bond, -CO-
O-, -O-CO-, -CO-S-, -S-CO-,-
CO-Se-, -Se-CO-, -CO-Te-, -T
e-CO -, - (CH 2 CH 2) ka - (ka is 1 to 4),
-CH = CH-, -C≡C-, -CH = N-, -N = C
_{H -, - CH 2 -O -} , - O-CH 2 -, - CO- or -
Represents 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, -OC
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, -C
_{O-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—, rc and rd are independently 1 to 20, and sa is the respective (C _sa H _2sa −).
O) independently from 1 to 10, ta from 1 to 6, p
b is 0-4. 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 -O-CO-
_{C qc} H 2qc -R ⁶ represents a linear, it may be either branched (wherein, R ⁶ is _{-O-CO-C qd H 2qd} + 1, -
_{CO-O-C qd H 2qd} + 1, -Cl, -F, -CF 3, -N
Represents O ₂ , —CN, or —H, qc and qd are each independently an integer of 1 to 20, and wa is an integer of 1 to 10). R
^5, (C _xb F _2xb -O) represented by _za -C _ya F _{2ya + 1} (where the above formula xb is each (C _xb F _2xb -O)
Is independently 1 to 10, ya is 1 to 10, za
Is 1 to 10.) ] 16. A liquid crystal device comprising at least the liquid crystal element according to claim 1 and means for driving the liquid crystal element.