JPH1114998A - Liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a defect in writing and seizure by making the hysteresis small. SOLUTION: When the impedance observed by applying a voltage to a passivation film 7 along its thickness and the impedance observed by applying a voltage in the reverse direction are different from each other, |Zratio |t/((εL.ρ1 ).(d1 /dL>)) holds, where Zratio is the ratio of the two different impedance values, εL the dielectric constant of liquid crystal 5, (t) a basic pulse interval for driving the liquid crystal element 1, ρ1 the volume resistivity of the passivation film 7, d1 the film thickness of the passivation film 7, and dL the thickness of the liquid crystal 5. Consequently, the hysteresis can be made small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical modulator using liquid crystal, and more particularly to a computer terminal display, a word processor, a typewriter, a television receiver, a video camera viewfinder, a projector light valve, a liquid crystal printer light valve, and the like. The liquid crystal element used for the liquid crystal display device, particularly, a liquid crystal exhibiting a chiral smectic phase (a liquid crystal exhibiting ferroelectricity or antiferroelectricity and driven by utilizing the action of spontaneous polarization) is preferably used. The present invention relates to a liquid crystal element exhibiting display characteristics.

[0002]

2. Description of the Related Art Conventionally, a CRT has been known as a display for displaying various information.
It is widely used in TVs and VTRs that output moving images, or in monitors of personal computers.

However, this CRT has a problem in that, due to its characteristics, flicker and scanning stripes due to lack of resolution lower visibility and cause deterioration of a fluorescent lamp due to burn-in for a still image. is there. Also, recently, electromagnetic waves generated by a CRT adversely affect the human body,
It has been found that DT workers may be harmed. Further, the CRT requires a space behind the screen due to its structure, which hinders space saving in offices and homes.

There is a liquid crystal element as a display for solving such a drawback of the CRT. As one of the liquid crystal devices, twisted nematic (twisted nematic) is used.
The use of nematic (TN) liquid crystals is known and is described in the Applied Physics Letters by M. Schadt and W. Helfrich.
Physics Letters), Vol. 18, No. 4 (issued on Feb. 15, 1971), pp. 127-12.
8 ".

As one of the liquid crystal elements using the TN liquid crystal, there is a simple matrix type which has an advantage in cost. However, this type of liquid crystal element is not suitable for a liquid crystal element having a high pixel density. Since crosstalk occurs during the division driving, the pixel density is limited.

In recent years, a liquid crystal element called a TFT has been developed for such a simple matrix type. In this TFT, since a transistor is formed for each pixel, the problems of crosstalk and response speed can be solved. However, as the area becomes larger, defective pixels are more likely to occur and the yield decreases. is there.

On the other hand, a display element of the type which controls transmitted light by combining with a polarizing element utilizing the refractive index anisotropy of ferroelectric liquid crystal molecules (liquid crystal molecules exhibiting ferroelectricity) is known as Clark. (Clark) and Lager Wall (La)
gerwall) (Japanese Unexamined Patent Publication No. Sho 56-56).
No. 107216, U.S. Pat. No. 4,367,924). This ferroelectric liquid crystal generally has a chiral smectic C phase (SmC *) or H
Phase (SmH *), in which state it takes one of a first optically stable state and a second optically stable state in response to an applied electric field, and its state when no electric field is applied. It has a property of maintaining a state (that is, a bistable memory property), and also exhibits a very fast response speed because of inversion switching by spontaneous polarization. Furthermore, since the visual characteristics are also excellent, it is considered that they are particularly suitable as high-speed, high-definition, large-screen display elements or light valves.

Recently, Chandani, Takezoe et al. Have proposed a liquid crystal element using a liquid crystal exhibiting antiferroelectricity (hereinafter referred to as "antiferroelectric liquid crystal") (J.
aperture Journal of Applier
d Physics Vol. 27, L729, 1988
page). This antiferroelectric liquid crystal, like the ferroelectric liquid crystal,
A display element is formed by utilizing the refractive index anisotropy and spontaneous polarization of liquid crystal molecules. Also, this antiferroelectric liquid crystal
Generally, in a specific temperature range, chiral smectic C
It has an A phase (SmCA *). In this state, when no electric field is applied, the average optical stable state is in the direction of the normal to the smectic layer. It has three stable states. Since the liquid crystal element using the antiferroelectric liquid crystal performs switching using spontaneous polarization as described above, it exhibits a very fast response speed and a high-speed display element or light valve. It is expected as.

In a liquid crystal device using a liquid crystal exhibiting such a chiral smectic phase (ferroelectric liquid crystal and antiferroelectric liquid crystal), for example, the structure and physical properties of a ferroelectric liquid crystal (Corona, Fukuda Atsuo, Hideo Takezoe,
(1990), the chiral smectic liquid crystal has two chevron structures, which causes a zigzag alignment defect, resulting in a significant decrease in contrast.

In order to prevent such alignment defects and maintain good contrast, a liquid crystal element using a bookshelf structure or a structure having a small layer tilt angle close to the bookshelf structure instead of the chevron structure has been proposed. ("Next-generation liquid crystal displays and liquid crystal materials;
CMC Corporation, edited by Atsuo Fukuda, 1992 ”). As a liquid crystal material exhibiting a “bookshelf or similar structure”, a liquid crystal compound having a perfluoroether side chain (US Pat. No. 5,262,082, International Patent Application WO 93/22396, 1993, 4th ferroelectric liquid crystal) International Conference P46, Marc D. Radcliffe
). This liquid crystal can exhibit a “bookshelf or similar structure” without using an external field such as an electric field.
It is suitable for high-speed, high-definition, large-area liquid crystal elements and display devices.

A liquid crystal device of this type is disclosed in
As disclosed in Japanese Patent No. 0930 and others, a pair of transparent substrates are provided at positions separated by a predetermined distance, and a liquid crystal is sandwiched between the pair of substrates. On one transparent substrate, an alignment control film having uniaxial alignment characteristics with respect to liquid crystal molecules is formed. On the other transparent substrate, characteristics such as non-uniaxial alignment characteristics with respect to liquid crystal molecules are formed. Different types of orientation control films are formed. According to this liquid crystal element, the orientation of the liquid crystal can be controlled in a high order from the side of the substrate that has been subjected to the uniaxial orientation treatment, and a favorable liquid crystal alignment state can be easily obtained.

[0012]

However, in such a liquid crystal device, although the orientation state is apparently good, asymmetrical characteristics appear in the switching or the good bistability of the liquid crystal is hindered. In some cases, so-called switching memory performance is reduced.

In particular, the symmetry of the switching characteristics is important for widening the driving margin, and it is necessary to maintain the symmetry of the switching characteristics even when driving is continued for a long time.

In addition, especially in a liquid crystal device using a ferroelectric liquid crystal or an antiferroelectric liquid crystal, in performing halftone display, an anti-electric field effect induced by spontaneous polarization of the liquid crystal itself is a serious problem. It has become. That is, a desired halftone may be destabilized due to a reason that the internal ions unevenly distributed in response to the spontaneous polarization form an electric field, and hysteresis may occur in an optical response to an externally applied voltage. This is because ions are localized in a direction that stabilizes each state with respect to the direction of spontaneous polarization of liquid crystal molecules when displaying “black state” or “white state”. Due to this difference, even when the voltage Vw applied after a short reset ("black erasure") is applied equally, the previous state ("white" or "black")
It is thought that this occurs because the voltage applied to the liquid crystal portion differs.

As an extremely inconvenient phenomenon due to the above-mentioned anti-electric field effect, for example, when the “black state” is set as the reset direction and the “white state” is written, the “white state” is obtained at a desired voltage level. Cannot be latched, and a so-called switching failure occurs, in which the signal is returned to the “black state”. This phenomenon is a fatal defect even in a liquid crystal element that does not require a halftone at a pixel level.

As a measure against the above-described anti-electric field effect,
For example, in JP-A-63-12020, etc.,
A method of reducing the impedance of an alignment control film constituting a ferroelectric liquid crystal element, that is, a method of coping with switching failure due to a so-called anti-electric field is disclosed. In addition, Japanese Unexamined Patent Application Publication No.
In JP-A-153321, many examples of an organic conductive film for lowering the impedance of an alignment control film are disclosed. Furthermore, Japanese Patent Application Laid-Open No. 64-49023 discloses that a thin film orientation layer is formed for passivation for preventing short circuit with reduced impedance, but at present, there is no sufficient solution.

As described above, the electro-optical characteristics of the liquid crystal device using the chiral smectic liquid crystal are controlled by the change of the threshold value caused by the control of the alignment state and the anti-electric field generated by the spontaneous polarization Ps, and the threshold voltage caused by the pre-standing state. However, there are problems to be improved with respect to optical response instability, etc. In this respect, the antiferroelectric liquid crystal element has the same problem.

[0018]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and comprises a pair of substrates arranged at a predetermined distance, a liquid crystal sandwiched between the pair of substrates, and A liquid crystal element in which one substrate has uniaxial alignment characteristics with respect to liquid crystal molecules. At least one of the pair of substrates has an electrode and an electrode provided on the liquid crystal side of the electrode and has electrical characteristics. The impedance observed when a voltage is applied in one thickness direction between the electrode and the layer having different electrical characteristics from the electrode, and the impedance observed when a voltage is applied in the opposite direction. Unlike

[0019]

[Formula 2] Z _ratio ≦ t / ((ε _L · ρ _I ) · (d _I / d _L )) where Z _ratio : the electrode and the electrode provided on the liquid crystal side of the electrode and the electrical characteristics. The ratio between the impedance observed when a voltage is applied in the direction of one film thickness to the different layers and the impedance observed when a voltage is applied in the opposite direction ε _L ; dielectric constant t of the liquid crystal; driving the liquid crystal element Basic pulse interval ρ _I ; volume resistivity d _{I of a} layer provided on the liquid crystal side of the electrode and having different electrical characteristics d _I ; different in electrical characteristics from the electrode provided on the liquid crystal side of the electrode The thickness d _{L of the} layer; the thickness of the liquid crystal is satisfied.

Preferably, the liquid crystal element of the present invention has one substrate having uniaxial alignment characteristics for liquid crystal molecules and the other substrate having non-uniaxial alignment characteristics for liquid crystal molecules. An electrode having the above characteristics and a structure of a layer having electric characteristics different from those of the electrodes are provided on a substrate having a uniaxial orientation characteristic.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

A liquid crystal device according to one embodiment of the present invention
There is provided a pair of substrates which are arranged at a predetermined distance from each other, and a liquid crystal is interposed between them. Preferably, one substrate has uniaxial alignment characteristics for liquid crystal molecules, and the other substrate has non-uniaxial alignment characteristics for liquid crystal molecules (hereinafter, only one substrate has A device configuration having uniaxial alignment characteristics with respect to liquid crystal molecules is referred to as an “asymmetric configuration”). Further, the substrate having the non-uniaxial alignment characteristic is provided with an electrode and a layer provided on the liquid crystal side of the electrode and having a different electric characteristic from the electrode. Further, * the impedance observed by applying a voltage in the thickness direction of a layer of the substrate having the non-uniaxial orientation characteristics and a layer having electrical characteristics different from that of the electrode provided on the liquid crystal side of the electrode; The ratio to the impedance observed when a voltage is applied in the opposite direction is Z _ratio , * the dielectric constant of the liquid crystal is ε _L , * the basic pulse interval for driving the liquid crystal element is t, * the non-uniaxial alignment. Let ρ _I be the volume resistivity of a layer having electrical characteristics different from that of the electrode provided on the liquid crystal side of the electrode on the substrate having the characteristics, and * the layer provided on the liquid crystal side of the electrode on the substrate having the non-uniaxial alignment characteristics. When the thickness of the layer having electrical characteristics different from that of the electrode is d _I and the thickness of the liquid crystal layer is d _L , Z _ratio ≦ t / ((ε _L · ρ _I ) · (d _I / d _L) )) Is established.

In this case, if the volume resistivity of the layer having different electric characteristics from the electrodes on the substrate having the non-uniaxial orientation characteristics is set to 1 × 10 ⁶ Ωcm to 1 × 10 ⁹ Ωcm, the crosstalk between adjacent pixels can be reduced. This is preferable because high resolution can be maintained without any problem. On the surface of the substrate having the uniaxial orientation characteristics,
A uniaxial alignment film having uniaxial alignment characteristics for liquid crystal molecules may be formed. Further, it is preferable that a layer provided on the liquid crystal side of the electrode on the substrate having the non-uniaxial alignment characteristic and having a different electrical characteristic from the electrode is a layer which is in contact with the liquid crystal and has a non-uniaxial alignment characteristic with respect to the liquid crystal. .

FIG. 1 is a sectional view showing an embodiment of a liquid crystal device according to the present invention. The liquid crystal element 1 shown in FIG. 1 includes a pair of substrates 2 and 3 arranged at a predetermined distance from each other, and a liquid crystal 5 is sandwiched between the substrates 2 and 3. An electrode 9 is formed on the surface of one of the substrates 2 (hereinafter, referred to as a “uniaxially aligned substrate 2”), and has uniaxial alignment characteristics with respect to liquid crystal molecules so as to cover the electrode 9. Uniaxial alignment film (hereinafter, referred to as “alignment control film”) 10
Are formed. Further, an electrode 6 is formed on the surface of the other substrate 3 (hereinafter, referred to as “non-uniaxial alignment side substrate 3”). The non-uniaxial alignment film 7 is formed.

In this embodiment, it is preferable to control the film-forming conditions and the like on each substrate so that the non-uniaxial alignment film 7 provided on the liquid crystal side of the electrode 6 on the non-uniaxial alignment side substrate 3 side. , The impedance characteristics are set.

It should be noted that the term “uniaxial orientation characteristics” in this specification
Means a uniaxial alignment state of liquid crystal molecules (for example, a uniaxial horizontal alignment state).

Uniaxially oriented substrate 2 and non-uniaxially oriented substrate 3
Is formed of a material having a property of transmitting light (eg, glass or plastic).

The orientation control film 10 may exhibit uniaxial orientation characteristics by being subjected to a uniaxial orientation treatment, or may have uniaxial orientation characteristics without such treatment.

In the former case (a material exhibiting a uniaxial orientation characteristic by performing a predetermined treatment), the material may be an inorganic material (silicon monoxide, silicon dioxide, aluminum oxide, zirconia, magnesium fluoride, cerium oxide, fluoride fluoride). Cerium, silicon nitride, silicon carbide, boron nitride, etc.) and organic substances (polyvinyl alcohol, polyimide, polyimide amide, polyester, polyamide, polyesterimide, polyparaxylene, polycarbonate, polyvinyl acetal, polyvinyl chloride, polystyrene, polysiloxane, cellulose) Resin, melamine resin, urea resin, acrylic resin, etc.), and as a method of forming a film of such a material, a method of directly applying these inorganic or organic substances in a solution state,
An evaporation method and a sputtering method may be used.
As the uniaxial orientation treatment, a rubbing treatment performed with a fibrous material such as velvet, cloth or paper is preferable.

A specific example of the latter (having uniaxial orientation characteristics without any treatment) includes a case where an oxide film or a nitride film of silicon (Si) is obliquely deposited. In this case, by adjusting the conditions of the oblique deposition, a uniaxial orientation characteristic can be obtained without performing the above-described rubbing treatment.

The thickness of the orientation control film 10 is set at 200 from the viewpoint of suppressing the magnitude of the anti-electric field generated with the switching of the spontaneous polarization Ps and having good switching performance.
It is preferably equal to or less than {} (or equal to or less than 100 °).

As the orientation control film 10, a polyimide represented by the following formula may be used.

[0033]

Embedded image Further, specific structures of these polyimides include, for example, the following repeating unit structures.

[0034]

Embedded image

[0035]

Embedded image Further, as the non-uniaxially oriented film 7, for example, a polycrystalline metal oxide film or a polycrystalline semiconductor film to which conductivity control impurities are added as necessary can be used. Specifically, Zn
An oxide of an element of group 12 (group number according to IUPAC inorganic chemical nomenclature; the same applies hereinafter) such as O, CdO, and ZnCdOx;
GeO ₂ , SnO ₂ , GeSnOx, TiO ₂ , ZrO
_2. An oxide of a Group IV element or a Group 14 element such as TiZrOx or a Group 14 semiconductor of Si or SiC to which a conductivity controlling impurity is added as necessary. Here, as the conductivity control impurity, for example, B, Al, Ga, and In which are Group 13 elements as n-type impurities with respect to Group 12 oxide,
Cu, Ag, A, which are Group 1 and 11 elements as p-type impurities
u and Li are used. In addition, P, As, Sb, which are Group 15 elements as n-type impurities with respect to Group 4 and 14 oxides,
Li is a group 13 element B, Al,
Ga and In are used. Also, “Ultra fine particles such as oxides described above (ultra fine particles such as oxides of Group 12, Group 4, and Group 14)
To which p-type or n-type conductivity controlling impurities are added "
Can be used as the non-uniaxially oriented film 7 in a predetermined base material (oxide base material, silica or siloxane polymer base material). It is particularly preferable to use a coating type film in which ultrafine particles of SnO ₂ doped with a conductivity control impurity such as Sb are dispersed in a base material such as silica or a siloxane polymer. When the surface potential of the uniaxially oriented substrate 2 is positive, a donor (n-type impurity) is added to the non-uniaxially oriented film 7 side, and when the surface potential is negative, an acceptor (p-type impurity) is added. The concentration of the impurity to be added varies depending on the type of the material and the crystallization state (the crystal defect density), but an approximate rule of thumb is that the concentration of free electrons or free holes in the material is 1 × 10 ¹¹ to 1 ×. What is necessary is just to set it as about 10 < ¹⁴ > / cm < ³ >. At this time, the surface potential is simultaneously changed by about 100 mV. In the case of using a polycrystalline material, it is preferable to consider 1 × 1
0 ¹⁷ -1 × 10 ²⁰ / cm ³ (0.0
(About 1% to 1%) is the actual addition amount. The amount of change in the surface potential with respect to the amount of impurity added is equivalent to about 50 mV with an increase of one digit.

When the conductivity control impurity is added to the non-uniaxially oriented film 7 as described above, the surface potential (the uniaxially oriented substrate 2
And the fine control of the surface potential detected on the surface of the non-uniaxially oriented substrate 3 and the difference between the two surface potentials (the surface potential detected on the surface of the uniaxially oriented substrate 2 and the non-uniaxially oriented substrate 3). 3), it is easy to set the absolute value of the difference (from the surface potential detected on the surface 3) to a small value (100 mV or less, preferably 50 mV).

The volume resistivity of the non-uniaxially oriented film 7 in the film surface direction is preferably in the range of 1 × 10 ⁶ to 1 × 10 ⁹ Ωcm. Thereby, crosstalk between pixels can be sufficiently prevented. Note that the volume resistivity of the non-uniaxial alignment film 7 may be adjusted by selecting the material.

In the present invention, according to the alignment characteristics of the liquid crystal material to be used, an alignment control film is used in which one substrate is subjected to a uniaxial alignment treatment with a film selected from the above-mentioned organic materials such as polyimide, and the other substrate is used. In the above, films (coated films) in which the above-mentioned oxide ultrafine particles and the like are dispersed in a base material can be used.

The electrodes 6 and 9 are made of ITO.
A transparent conductor such as (indium tin oxide) is preferred. The electrodes 6 and 9 are, as shown in FIG.
A large number of stripes may be formed at a constant pitch, and the electrodes 6 and the electrodes 9 may be formed so as to intersect each other.

Next, the liquid crystal composition used in the present invention will be described.

As the liquid crystal 5 used in the present invention, a liquid crystal exhibiting a chiral smectic phase (that is, a liquid crystal exhibiting ferroelectricity or a liquid crystal exhibiting antiferroelectricity, in which the action of spontaneous polarization is applied to driving). However, nematic liquid crystal or the like may be used. When a liquid crystal exhibiting a chiral smectic phase is used, the thickness of the liquid crystal is
From the viewpoint of ensuring bistability, the thickness is preferably 5 μm or less.

For example, a liquid crystal exhibiting a chiral smectic phase is a material having an isotropic phase → SmA → SmC * → crystal phase from a high temperature side to a low temperature side as a phase transition series, and has a spontaneous polarization of 30 nC / Preferably, the tilt angle is about 24 degrees in cm ² (at a temperature of about 30 ° C.).

Further, in the liquid crystal device of the present invention, in order to improve the luminance at the time of display, when the liquid crystal takes the SmC * phase, the bookshelf structure in which the smectic layer is vertically arranged in parallel to the substrate, or It is preferable to use a liquid crystal material having a structure with a smectic layer inclination close to the above.
As a liquid crystal material having such a smectic layer structure, for example, a composition using a fluorine-containing liquid crystal compound having a structure in which a fluorocarbon terminal portion and a hydrocarbon terminal portion are bonded to a central nucleus and exhibiting a smectic phase or a potential smectic phase Is mentioned. Such fluorine-containing compounds are specifically described in US Pat. No. 5,082,
No. 587, US Pat. No. 5,262,082, International Publication W
Fluorine-containing compounds described in O93 / 22936 and the like can be used.

More specifically, the compound is a nuclear fluorine-containing compound, and is, for example, an isotropic phase at a temperature lowering as described above → SmA
A liquid crystal material exhibiting a phase transition such as → SmC * → crystal phase (in particular, not exhibiting a cholesteric phase) may be used.

According to the present embodiment, since the liquid crystal element has an asymmetric structure in which only one side of one substrate 2 is subjected to uniaxial alignment treatment, the liquid crystal (particularly, ferroelectric or antiferroelectric liquid crystal) is preferably made of SmA. Is performed as uniaxial molecular growth from the surface of one of the substrates 2 which has been subjected to the uniaxial orientation treatment, and a good orientation state can be obtained in the SmC * phase. In particular, when a liquid crystal that does not exhibit the cholesteric phase described above is used, a uniform alignment state can be realized by performing good alignment control during the phase transition from I (isotropic phase) to SmA at a reduced temperature. .

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.

[0048]

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).

[0055]

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 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) is
JP-A-2-142755, U.S. Pat.
2,587.
Specific examples of such compounds are listed below.

[0063]

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[0064]

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[0065]

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[0066]

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[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]

Embedded image The compound represented by the above general formula (II) is disclosed in International Publication W
O93 / 22396 and JP-T-7-506368. Specific examples of such compounds are listed below.

[0075]

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[0076]

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[0077]

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[0078]

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[0079]

Embedded image In the liquid crystal composition used in the liquid crystal element of the present invention, in addition to the above-mentioned fluorine-containing liquid crystal compound, a so-called hydrocarbon type liquid crystal compound having no fluorocarbon chain can be blended. Specific examples include those having the following structures.

[0080]

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[0081]

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[0082]

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[0083]

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[0084]

Embedded image Further, in the liquid crystal composition exhibiting a chiral smectic phase used in the present invention, it is essential to incorporate at least one optically active compound. Such an optically active compound can be selected from compounds having a chain or cyclic optically active site in consideration of compatibility with other liquid crystal components such as the above-mentioned fluorine-containing liquid crystal compound. Specific examples are shown below.

[0085]

Embedded image

[0086]

Embedded image

[0087]

Embedded image

[0088]

Embedded image

[0089]

Embedded image

[0090]

Embedded image

[0091]

Embedded image

[0092]

(Equation 3)

[0093]

[Table 1]

[0094]

[Table 2]

[0095]

[Table 3]

[0096]

[Table 4]

[0097]

[Table 5]

[0098]

Embedded image

[0099]

Embedded image

[0100]

Embedded image The above-mentioned chiral smectic liquid crystal may contain additives such as a dye, a pigment, an antioxidant, and an ultraviolet absorber.

The volume resistivity of the non-uniaxially oriented film 7 in the film surface direction is preferably in the range of 1 × 10 ⁶ to 1 × 10 ⁹ Ωcm. Thereby, crosstalk between pixels can be sufficiently prevented. Note that the volume resistivity of the non-uniaxial alignment film 7 may be adjusted by selecting the material.

Incidentally, the time constant τ of dielectric relaxation in the liquid crystal device of the embodiment shown in FIG. 1 is a product of the capacitance C _{L of} the liquid crystal and the resistance R _I of the non-uniaxial alignment film 7 formed on the electrode 6. represented, the τ ≒ C _L · R _I. Here, C _L = ε _L · (S / d _L ), R _I =
From (d _I / S) · ρ _I , τ = ε _L · ρ _I · (d _I / d _L ).

On the other hand, when writing information to each pixel of the liquid crystal element 1, assuming that the basic pulse width of the applied voltage is t, the dielectric relaxation must be performed within this time t.

[0104]

[Formula 4] It is necessary to satisfy τ = ε _L · ρ _I · (d _I / d _L ) ≦ t.

Incidentally, the volume resistivity ρ of the non-uniaxial alignment film 7
_{Since I} is generally high, rectification occurs in taking in and out of the electric charge in a portion in contact with the electrode, and may exhibit different impedances (Z +, Z-) depending on the direction of voltage application. That is, when a voltage is applied to the non-uniaxially oriented film 7 in the thickness direction, the observed impedance differs depending on the voltage application direction. Then, the switching speed decreases in the one with the larger impedance, and the driving margin also decreases.

Here, the ratio of the absolute value of the large impedance to the absolute value of the small impedance (hereinafter referred to as “impedance polarity ratio”) Z _ratio is

[0107]

[Equation 5] Z _ratio = max (| Z− | / | Z + |, | Z
+ | / | Z− |), when | Z− | <| Z + |, Z _ratio
= | Z + | / | Z- |, and when | Z- |> | Z + |, Z _ratio = | Z− | / | Z + |. And
The one with the smaller impedance (ie, (d _I / S)
In _{ρ I), τ = ε L} · ρ I · ( must meet the _{d I / d L) ≦ t} , the larger the impedance _{(i.e., Z ratio · (d I /} S) · ρ I) , It is necessary to satisfy τ ′ = Z _ratio · ε _L · ρ _I · (d _I / d _L ) ≦ t.

That is, regardless of the magnitude of the impedance,

[0109]

[Equation 6] It is necessary to satisfy Z _ratio ≦ t / ((ε _L · ρ _I ) · (d _I / d _L )), and when this equation is satisfied, a decrease in the drive margin is prevented. You.

In other words, the dielectric relaxation at the time of switching tends to be slower due to the rectifying property of the non-uniaxially oriented film, and the margin may be reduced. Does not occur.

In particular, the volume resistivity of the non-uniaxially oriented film 7 is set to 1 × 1 so as to obtain a resistance of several tens of mega-ohms or more as a resistance between adjacent layers.
When using a waveform of about ⁶ to 1 × 10 ⁹ Ωcm, the polarity ratio of the impedance of 10 to 100 is a value that affects the relaxation time constant of the liquid crystal when a waveform around microseconds is used as the panel drive pulse. Therefore, eliminating the polarity ratio of impedance is effective for securing a margin.

When there is no difference between Z + and Z-, Z _ratio = 1, and Equations 6 and 4 match.

Next, means for measuring the resistance value of a film such as the non-uniaxially oriented film 7 will be described with reference to FIGS.

FIG. 3 is a diagram showing a system for measuring a resistance value in a film thickness direction of a film. Reference numeral 20 denotes a film to be measured, and a current is applied between an electrode 21 and an electrode 22. The measurement is performed while flowing. Here, one electrode 21 is
An electrode made of Al having a diameter of 1 mmφ and the other electrode 2
Reference numeral 2 denotes an electrode made of ITO.

FIG. 4 is a diagram showing a system for measuring the resistance value of the film in the film surface direction.
This is a film to be measured, and a current is applied between the electrode 25 and the electrode 26 to perform measurement.

In the present invention, in particular, in the embodiment shown in FIG. 1, a predetermined inorganic film is provided on the substrate side (for example, between the non-uniaxially oriented film 7 and the electrode 6) with respect to the non-uniaxially oriented film 7. It may be provided to further increase the breakdown voltage. Thereby, the durability of the element can be increased.

As such an inorganic film, ZnO, Sn
A vapor-deposited film formed by various sputtering methods such as O ₂ or TaOx is suitable. For example, by adjusting the gas pressure of an oxygen gas, an argon gas or the like, or by adjusting the RF power, the resistivity in the film thickness direction is set to 1 × 10 ⁴ -1 × 10
A film having a thickness of about 1000 to 2000 mm controlled to ⁸ Ωcm can be optimally used.

When such an inorganic film is provided, the upper limit of the volume resistance in the film thickness direction is about 1 × since it is necessary to cancel the state before switching, similarly to the non-uniaxially oriented film 7.
It is preferably about 10 ⁸ Ωcm.

On the other hand, the same applies to the lower limit value and the upper layer film. For example, even if the liquid crystal portion is short-circuited due to the incorporation of a conductive foreign substance or the like, it flows in the thickness direction of the deposited film. By suppressing the current, it is derived based on a condition for preventing a defect in image quality from being noticeable in or around the short portion. As an example of a typical idea, when an electric path is generated in a liquid crystal portion in a film thickness direction by a foreign substance having a thickness of about the cell, in order to reduce the above-described voltage drop rate between pixels to 1/100, The resistance of this portion is required to be 100 times the resistance of 1 kΩ from the feeding portion to the pixel end. If the short area is 2 μm × 2 μm and the thickness of the inorganic film is 1000 °, ρ _min · 1 · 10 ⁻⁵ /
From (2 · 10 ⁻⁴ ) ² ≧ 1 · 10 ⁵ (Ω) (ρ _min : lower limit of resistance), ρ _min ≧ 4 · 10 ² (Ωcm),
For example, assuming a path at a plurality of locations, about 1 × 10 ⁴ Ω
cm or more is required.

Next, a case where the liquid crystal display device 30 is configured using the above-described liquid crystal element 1 will be briefly described with reference to FIGS.

FIG. 5 is a block diagram showing the entire configuration of the liquid crystal display device. As shown in FIG. 5, an information line driving circuit 405 and a scanning line driving circuit 404 are connected to the liquid crystal element 1. The drive control circuit 411 and the graphic controller 402 are sequentially connected to these circuits 404 and 405. The graphic controller 402 includes a GCPU (Central Processing Unit) 412, a host CPU 413, and a VRAM 414,
Manages image information and communicates. GCPU4
Image information and a SYNC signal are transmitted from 12 to the drive control circuit 411, and this image information includes scanning line address information and display information as shown in FIG. The scanning line address information is sent to the scanning line driving circuit 404, and the display information is sent to the information line driving circuit 405.

Further, the scanning line driving circuit 404 applies a scanning signal to the electrode 9 determined by the scanning line address information, and the information line driving circuit 405 applies the information signal. Note that a light source (not shown) is disposed on the back surface of the liquid crystal element 1, and the light source illuminates the liquid crystal element 1.

Since the liquid crystal element 1 has good switching characteristics as described above, the liquid crystal display device 3 shown in FIG.
No. 0 exhibits excellent driving characteristics, and becomes a high-definition, high-speed, large-area display device.

Next, a method of driving the liquid crystal element 1 will be described with reference to FIG.
This will be described with reference to FIG.

As a driving method of the liquid crystal element 1 described above, for example, JP-A-59-193426 and JP-A-59-1
93427, JP-A-60-156046,
The driving method disclosed in Japanese Patent Application Laid-Open No. 60-156047 or the like may be applied.

FIG. 7 is a waveform diagram showing the waveform of each signal applied to the electrode. The signal indicated by reference numeral S _S in FIG. 7 (a) shows a selection scan waveform applied to the selected scanning line, a signal indicated by reference numeral S _N is a non-selection scanning waveform that is not selected Is shown. The signal indicated by symbol I _S shows the selection information signal to be applied to the selected information line (black), signal indicated by reference numeral I _N is a non-selection data signal to be applied to the information line which is not selected (White).
Further, reference numeral "I _S -S _S" and "I _N -S _S" indicates a voltage waveform applied to the pixel on a selected scanning line, the voltage indicated by reference numeral "I _S -S _S" the applied pixel takes a black display state, the code "I _N -S _S" pixels to which the voltage is applied as shown in the expects a display state of white.

Here, a driving example of the liquid crystal element 1 is shown in FIG.
This will be specifically described with reference to FIG.

Now, let us consider a case where the display as shown in FIG. 8 is performed on six pixels. The information lines constituting these pixels are indicated by reference numerals I ₁ and I ₂ , and the scanning lines are indicated by reference characters S
Shall be indicated by _1, S _2, S _3.

FIG. 9 is a waveform diagram showing the waveform of the driving signal for performing the display shown in FIG. 8. In order to perform the display shown in FIG. 8, * 3 scanning lines S ₁ and S _{2 are provided.} , applies a selection scan signal S _S in the order shown in S _3, * when the scan lines S ₁ applies a selection scan signal S _S, the information lines I ₁ unselected information signal I _N At the same time, the selection information signal I _S is applied to the information line I _2. * When the selection scanning signal S _S is applied to the scanning line S ₂ , the information lines I ₁ and I ₂ are not applied. Selection information signal I _N
*, While the selection scanning signal S _S is being applied to the scanning line S ₃ , the selection information signal I _S may be applied to both the information line I ₁ and the information line I ₂ .

The scanning signal S _S shown in FIG. 7 is composed of a reset pulse (pulse width t ₁ ) and a write pulse (pulse width t ₂ ), but t ₁ = 2t ₂ (that is, t ₁ = 2t ₂ ).
_{When 2} = Δt, t ₁ = 2Δt). The previous display state is reset by a reset pulse (in this driving example, the white display state is reset).

The parameters of the driving waveform (V _S , V _S
I and Δt) are determined by the switching characteristics of the liquid crystal material used.

FIG. 10 shows the bias ratio V _I / (V _I + V
FIG. 6 is a diagram illustrating a relationship between the drive voltage (V _S + V _I ) and the transmittance T (that is, the VT characteristic) when the drive voltage (V _S + V _I ) is changed while keeping _S ) constant. . Here, Δt = 50 μsec, and the bias ratio V _I / (V _I + V
_S ) is fixed.

[0133] Then, the right side of FIG. 10 is pre-display state indicates the V-T characteristic in the case of applying the "waveform I _N -S _S (see FIG. 7)" to black pixels, 0 ≦ V _S + V _I ≦ V _2; not white reset, black (pre display state) range is held _{V 2 ≦ V S + V I} ≦ V 3; black (prior display state) is white reset, and white holding V ₃ ≦ V _S + V _I ; black (previous display state) is reset to white, indicating that black is written.

[0134] Further, the left side of FIG. 10 is pre-display state indicates the V-T characteristic in the case of applying the "waveform (see FIG. 7) of the I _S -S _S" to the pixels of the white, 0 ≦ V _S + V _I ≦ V _1; white (before display state) range is held _{V 1 ≦ V S + V I} ; white (before display state) is reset, indicating that the range that can not be white retained. Incidentally, the V ₁ described above is referred to as "actual driving threshold voltage".

That is, when the above-mentioned items are summarized, I _N −
When the S _S waveform is applied, white writing (white holding) is performed properly (see above), and when the I _S -S _S waveform is applied, black writing is performed properly (see above). ), V ₁ ≦ V _S + V _I ≦ V ₃ when V ₂ <V ₁ <V ₃ .

[0136] Here, V ₃ (hereinafter, referred to as "cross-talk voltage") is, V _B ¹ of the waveform "I _N -S _S" shown in FIG. 7
Is a voltage value (see above) at which black writing is performed, and it can be said that the voltage value generally exists when a chiral smectic liquid crystal element is driven. Then, the person crosstalk voltage V ₃ is large, preferably from the top of the drive.

[0137] Incidentally, it is sufficient to increase the bias ratio to increase the cross-talk voltage 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. According to our study, the bias ratio is 1/3 to 1
About / 4 was practical.

Now, if ΔV (hereinafter, referred to as “voltage margin parameter”) is defined as ΔV = (V ₃ −V ₁ ) / (V ₃ + V ₁ ), this voltage margin parameter ΔV is a matrix This is a parameter of the drivable voltage width. The larger the parameter ΔV, the better, and the parameter ΔV strongly depends on the switching characteristics and the element configuration of the liquid crystal material.

In the above description, the switching of the liquid crystal is performed by changing the voltage. However, the switching may be performed by changing the voltage application time Δt while keeping the voltage constant. In this case, M2 = (Δt ₂ −Δt ₁ ) / (Δt ₂ + Δt ₁ ) Here, Δt ₁ (voltage application time threshold) corresponds to the actual drive threshold voltage V ₁ , and Δt ₂ (voltage application time crosstalk value) is equivalent to the cross-talk voltage V _3. Voltage application time margin parameter (M
2), the larger the better.

The voltage margin parameter ΔV and the voltage application time margin parameter M2 are specific to the liquid crystal element, and differ depending on the liquid crystal material and the configuration of the liquid crystal element. Also, these parameters ， V, M2 are
It changes according to the environmental temperature. Therefore, it is necessary to optimize the driving conditions of the liquid crystal element according to the liquid crystal material, the configuration of the liquid crystal element, and the environmental temperature.

[0141]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to specific embodiments. (Embodiment 1) First, Embodiment 1 of the present invention will be described with reference to FIG.
This will be described with reference to FIGS.

In this embodiment, two types of liquid crystal elements (hereinafter, referred to as “liquid crystal element 1A” and “liquid crystal element 1B”) having the structure shown in FIG. "), The characteristics of these two types of liquid crystal elements 1A and 1B are compared, and the two types of samples 1LA and 1LB differing in the method of forming the non-uniaxial alignment film 7 and the like.
(Hereinafter referred to as “evaluation samples 1LA, 1LB”), and the non-uniaxially oriented film 7 was evaluated.

First, the liquid crystal elements 1A and 1B will be described.

The specific structure of the liquid crystal elements 1A and 1B is shown in FIG.
Is the same as the liquid crystal element 1 shown in FIG. That is, the liquid crystal element 1
A and 1B are a uniaxially oriented substrate (substrate) 2 and a non-uniaxially oriented substrate (substrate) arranged at positions separated by a predetermined distance.
A liquid crystal 5 is sandwiched between the substrates 2 and 3. An electrode 9 and an orientation control film 10 are formed on the surface of the uniaxial orientation side substrate 2.
0 is treated to uniaxially align the liquid crystal 5. Further, an electrode 6 and a non-uniaxial alignment film 7 are formed on the surface of the non-uniaxial alignment side substrate 3 so as to have non-uniaxial alignment characteristics with respect to liquid crystal molecules.

Next, a method for manufacturing the liquid crystal element 1A will be described.

First, a general DC sputtering apparatus and an ITO
An ITO film was formed on the surfaces of the substrates 2 and 3 by sputtering using a target of (indium tin oxide). In this sputtering, the power of the sputtering apparatus was set to 1 W / cm ^2, and a mixed gas of Ar and O ₂ (Ar: 90 SCCM, O ₂ : 1) was used as a sputtering gas.
0SCCM) and the discharge time is 2.5 minutes,
The thickness of the TO film was set to 700 °. Then, the ITO film was patterned into a desired shape by a normal wet etching method, and electrodes 6 and 9 were formed.

Next, the surface of one substrate (uniaxially oriented substrate) 2 is coated with polyamic acid (LP-64, manufactured by Toray Industries, Inc.).
Is spin-coated at 2700 rpm for 20 seconds,
This was baked at 200 ° C. for 60 minutes to form an orientation control film (polyimide film) 10 having a thickness of 50 °. Thereafter, the orientation control film 10 was subjected to rubbing three times in one direction at a rotation speed of 1000 rpm, a pushing amount of 0.4 mm, a feed speed of 5 mm / sec.

The other substrate (non-uniaxially oriented substrate) 3
(A solution in which ultrafine particles of SnOx having a particle size of about 100 ° are dispersed in a silicon oxide base material in which a ladder-type polysiloxane is mixed at a polymerization ratio of 40% with a polymer of SiOx) Is spin-coated at 1000 rpm for 10 seconds, and baked at 200 ° C. for 60 minutes.
A non-uniaxially oriented film 7 having a thickness of 2000 ° was formed.

Next, the alignment control film 10 of the uniaxial processing side substrate 2
A solution containing 2.2 μm-diameter SiO ₂ fine particles was applied to the surface by spin coating, and heated to disperse and fix the SiO ₂ fine particles on the surface of the orientation control film 10. Further, a solution containing adhesive particles (epoxy resin particles) having a particle size of about 5 μm was applied by a spin coating method, and heated again to disperse and fix the epoxy resin particles.

Further, a sealant is applied to a desired position of the non-uniaxial processing side substrate 3 by using a printing machine, and this is applied at 90 ° C. for 5 minutes.
Prebaked for minutes.

Further, the substrate 2 and the substrate 3 were pressed with a press machine at a pressure of 50 gf / cm ² and heated at 110 ° C. for 90 minutes while applying the same pressure with an air cushion. The sealant was cured, and the two substrates 2 and 3 were bonded together.

Thereafter, the empty element formed by the above operation is put into a normal load lock type vacuum chamber, and the empty element is placed in a 1 × 10
^After evacuating to ^-5 Torr, 1 × 10 ^-2 Torr
The liquid crystal was heated to 95 ° C. in a vacuum and immersed so as to have an injection port, and the liquid crystal was injected into the empty element.

Next, a method for manufacturing the liquid crystal element 1B will be described.

The electrodes 6 and 9 were formed on the surfaces of the substrates 2 and 3 in the same manner as described above. An orientation control film (polyimide film) 10 was formed on the surface of one substrate (uniaxial orientation side substrate) 2 in the same manner as described above, and the surface of the orientation control film 10 was subjected to a rubbing treatment. .

Next, the other substrate (non-uniaxially oriented side substrate) 3
Is mixed with a predetermined solution (a solution in which ultrafine particles of SnOx oxide are dispersed in a silicon oxide matrix made of a polymer of SiOx, ie, a ladder-type polysiloxane unlike the liquid crystal element 1A). Not), 10
Spin coat under conditions of 00 rpm and 10 seconds,
It was baked at 00 ° C. for 60 minutes to form a non-uniaxially oriented film 7 having a thickness of 2000 °.

Further, after the dispersion and fixation of the SiO ₂ fine particles and the adhesive particles, the application of the sealant, and the like were performed in the same manner as described above, the two substrates 2 and 3 were attached to each other, and the liquid crystal was injected.

Next, evaluation samples 1LA and 1LB for evaluating the non-uniaxial alignment film 7 will be described.

FIG. 11 is a sectional view showing a specific structure of the evaluation sample. As shown in FIG.
A and 1LB have only one substrate 3 and this substrate 3
On the surface of the ITO film 50 without patterning
Are formed. On the surface of the ITO film 50, a film 17 similar to the non-uniaxially oriented film 7 formed by the elements 1A and 1B is formed, and on the surface of the film 17, an ohmic contact layer 51 is formed. Further, on the surface of the ohmic contact layer 51, a plurality of ohmic electrodes 52 having a diameter of 1 mm and made of Al are formed. At the end of the substrate 3, a lead wire 53 is connected to the ITO film 50.

Here, a method of manufacturing the evaluation sample 1LA will be described.

First, an ITO film 50 was formed on the surface of the substrate 3 in the same manner as in the case of the liquid crystal elements 1A and 1B. In addition,
This ITO film 50 is not patterned, and the ITO film 5 is not patterned.
On the surface of No. 0, a film 17 was formed as in the case of the non-uniaxial alignment film 7 in the liquid crystal element 1A.

After forming the film 17 in this manner,
Using the same material as the film 17 (non-uniaxially oriented film 7), SnOx
Volume resistivity is 1 × 10 ⁴ Ωcm by increasing the concentration of ultrafine particles
An ohmic contact layer 51 was formed by spin-coating a film forming solution having a different formulation so as to take a value on the surface of the film 17. The spin condition was 150
At 0 rpm and 10 sec, the film thickness was set to about 500 °. Further, the ohmic contact layer 51
An ohmic electrode 52 was formed on the surface by using a normal resistance heating type vapor deposition machine. After that, the lead wire 53
It was joined to the O film 50 with ultrasonic solder.

Next, a method of manufacturing the evaluation sample 1LB will be described.

In the evaluation sample 1LB, the sample 1LA
An ITO film 50 is formed in the same manner as described above.
On the surface of No. 0, a film 17 was formed similarly to the non-uniaxial alignment film 7 in the liquid crystal element 1B. Other configurations and manufacturing methods are the same as those of the sample 1LA described above.

Next, a method of evaluating a film (non-uniaxially oriented film) formed on an electrode using the evaluation samples 1LA and 1LB will be described.

FIG. 12 is a schematic diagram for explaining a method for evaluating the film 17 (non-uniaxially oriented film in the device). When this film is evaluated, as shown in FIG. And the impedance measuring device 60 was connected to the ohmic electrode 52. Then, the impedance Z + when a DC voltage of +500 mV is applied to the ohmic electrode 52, and -500 to the ohmic electrode 52.
Impedance Z- when mV DC voltage is applied
And were respectively measured. As a result, the impedance polarity ratio Z _ratio was approximately “5” in the evaluation sample 1LA, and was approximately 30 in the evaluation sample 1LB. Thereby, between the sample 1LA and the sample 1LB,
It was found that the ability of the film 17 to move charges in and out was different.

Next, the liquid crystal element 1 prepared by the above-described method is used.
The characteristics of one pixel for A and 1B were examined.

FIG. 13 is a schematic diagram for explaining how to examine the characteristics of the liquid crystal element. When examining the characteristics of one pixel, as shown in FIG.
(Accurately, the electrode 6) is grounded, and the uniaxial processing side substrate 2
(Accurately, a signal voltage was applied to the electrode 9 side.

When the write signal voltage is changed, the relationship between the voltage and the light transmittance (VT characteristic) is shown in FIG.
It became as shown in.

Here, the difference between the direction of the arrow and the direction of the return shown in the figure is the amount called hysteresis, and ideally it is desirable to be "0", but practically, it is about 5% or less of the drive voltage. Good. The solid line U1 and the broken line U2 indicate which direction the spontaneous polarization of the liquid crystal molecules is oriented at the time of black reset. For example, when Ps is negative, U1 is directed toward the non-uniaxial alignment side, and U1 is directed toward the uniaxial alignment side. U2. When the respective states of U1 and U2 are set to the black state, it is desirable that the amount of deviation between the voltage thresholds is ideally also “0”. At this time, it is said that the symmetry is obtained. On the other hand, the threshold shift amount is also called asymmetry, and if the value is practically less than about ± 1 V, the bistable potential is not extremely disturbed, and a change over time such as writing failure or burn-in is caused. Is suppressed.

In the case of the liquid crystal element 1A, it was found that the hysteresis was suppressed to 0.6 V and the asymmetry was suppressed to about 0.2 V. In the case of the other liquid crystal element 1B, the asymmetry was 0.3 to 0.4 V, which is almost the same as the element 1A, but the hysteresis was increased to 1.2 V.

[0171] Here, consider the equation _{Z ratio ≦ t / ((ε} L · ρ I) · (d I / d L)).

In the case of this embodiment, t = 10 to 20 μsec
In the elements 1A and 1B, the thickness d _I of the non-uniaxial alignment film 7 is 2000 °, and the thickness d _L of the liquid crystal layer is 2 μm =
20000 °, and the dielectric constant ε _{L of the} liquid crystal is 1 × 10 ^−12.
(The relative dielectric constant is about 10), and the volume resistivity ρ _{I of the} film is
= 1 × 10 ⁷ Ωcm, the right side of the above equation is 10-2.
It becomes 0. In the case of the liquid crystal element 1A, the left side (Z
measured value of _ratio ) is 5, which satisfies the above expression. In the case of the liquid crystal element 1B, the left side (measured value of Z _ratio ) is 30.
However, the above formula is not satisfied. Therefore, according to the present embodiment, when the above equation is satisfied (in the case of the evaluation sample 1LA, that is, in the case of the liquid crystal element 1A), the hysteresis is small, and when the above equation is not satisfied (in the evaluation sample 1LB, that is, the liquid crystal element 1B). In the case of), the hysteresis becomes large, and it is understood that the hysteresis is appropriate as long as the above expression is satisfied.

Furthermore, it was confirmed that when the liquid crystal element 1A thus produced was driven, no afterimage was seen and a quick response was obtained. In addition, in this liquid crystal element 1A, no flickering or growth of a defective display area is observed, extremely good bistability is obtained, progress of image sticking and monostable are sufficiently suppressed, and high reliability is obtained. It was confirmed.

On the other hand, when the other liquid crystal element 1B was driven, afterimages, growth of defective display areas, and burn-in were somewhat observed.

On the other hand, the above-described voltage application time margin parameter M2 (= (Δt ₂ −Δt ₁ ) / (Δt ₂ + Δt)
₁ )) is 0.0% in the liquid crystal element 1B when the voltage application of the polarity with the higher impedance is reset.
Despite the decrease of 5 to 0.1, the liquid crystal element 1
In the case of A, the voltage was approximately 0.25 equally when resetting (the voltage of the polarity with the larger impedance and the voltage of the polarity with the smaller impedance). At this time, even if a voltage of 20 V is applied between the electrodes of the upper and lower substrates as the peak value of the driving voltage, the liquid crystal elements 1A and 1
In both B, no pixel in which short-circuit occurred was observed, and there was no trade-off that the short-circuit prevention function was reduced as a result of margin improvement. (Embodiment 2) Next, Embodiment 2 of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

In this embodiment, two types of liquid crystal elements (hereinafter, referred to as "liquid crystal element 2A" and "liquid crystal element 2A") having an asymmetric structure shown in FIG. A liquid crystal element 2B) is prepared, the characteristics of these two types of liquid crystal elements 2A and 2B are compared, and the method of forming a film on the non-uniaxial substrate side is different.
Sample 2LA, 2LB (hereinafter referred to as “evaluation sample 2L”).
A, 2 LB "), and the film was evaluated.

FIG. 15 is a cross-sectional view showing the specific structure of the liquid crystal elements 2A and 2B produced in this embodiment. As shown in FIG. 15, the liquid crystal elements 2A and 2B have non-uniaxial alignment sides. The substrate 3 has two layers 7a and 7b (hereinafter, the layer 7a on the substrate 3 side is referred to as a “lower layer 7a”, and the layer (non-uniaxially oriented film) 7b on the liquid crystal 5 side is referred to as an “upper layer 7b”). It is configured. Other configurations are the same as those of the liquid crystal element 1 described above.

Next, a method for manufacturing the liquid crystal element 2A will be described.

First, an ITO film was sputtered on the surfaces of the substrates 2 and 3 under the same apparatus and under the same conditions as in Example 1, and the ITO films were patterned to form electrodes 6 and 9.

Next, a solution prepared by diluting a polyimide having the following structural formula to a concentration of 0.8 wt% with a mixed solution of NMP and nBC (2: 1) is applied to the surface of one substrate (uniaxially oriented substrate) 3.
Spin coating was performed at 2,000 rpm for 20 seconds, and the resultant was baked at 200 ° C. for 60 minutes to form a 50 ° -thick alignment control film (polyimide film) 10.

[0181]

Embedded image Then, the rotation speed of 1000 rpm is applied to the orientation control film 10.
m, pushing amount 0.4mm, feed speed 10mm / s
ec, rubbing treatment was performed four times in one direction.

The other substrate (non-uniaxially oriented substrate) 3
On the surface of the substrate, an ordinary RF sputtering apparatus and ZnO (100
%), A lower layer 7a made of a ZnO film was formed to a thickness of 2000 °. Note that the power is 5
W / cm ² and the substrate heating temperature was 200 ° C. The sputtering gas is a mixed gas of Ar and O ₂ (Ar: 9).
0 SCCM, O ₂ : 10 SCCM) and the pressure is 3 m
Torr and the discharge time was 2 minutes.

Next, the surface of the lower layer 7a is coated with a solution (a particle size of about 100.degree.
A solution in which ultrafine particles of SnOx oxide are dispersed)
The film was spin-coated to a thickness of 2500 ° at a condition of 00 rpm and 10 seconds, and baked at 200 ° C. for 60 minutes to form an upper layer 7b.

Further, in the same manner as in Example 1, SiO
_After dispersing and fixing the _two fine particles and the V adhesive particles (epoxy resin particles), applying a sealant, and the like, the two substrates 2 and 3 were attached to each other, and liquid crystal was injected.

Next, a method for manufacturing the liquid crystal element 2B will be described.

The electrodes 6 and 9 were formed on the surfaces of the substrates 2 and 3 in the same manner as described above. An orientation control film (polyimide film) 10 was formed on the surface of one substrate (uniaxial orientation side substrate) 2 in the same manner as described above, and the surface of the orientation control film 10 was subjected to a rubbing treatment. . Further, on the surface of the other substrate (non-uniaxially oriented substrate) 3, a lower layer 7a was formed in the same manner as described above.

Next, a solution (S) is applied to the surface of the lower layer 7a.
A ladder-type polysiloxane mixed with an iOx polymer at a polymerization ratio of 40% in a silicon oxide matrix has a particle size of about 10%.
0 ° SnOx oxide ultrafine particles dispersed solution)
Spin coating was performed under the conditions of 1000 rpm and 10 seconds, and the resultant was baked at 200 ° C. for 60 minutes to form an upper layer 7b having a thickness of 1500 °.

Further, in the same manner as in Example 1, SiO
_After the dispersion and fixation of the _two fine particles and the adhesive particles, the application of the sealant, and the like, the two substrates 2 and 3 were attached to each other, and the liquid crystal was injected.

Next, the substrate 3 in the liquid crystal elements 2A and 2B
The evaluation samples 2LA and 2LB for evaluating the lower layer 7a and the upper layer 7b on the side will be described.

The evaluation samples 2LA and 2LB were composed of two layers, a lower layer 7a and an upper layer 7b, as in the case of the liquid crystal elements 2A and 2B described above. Other configurations (namely, ITO film 50, ohmic contact layer 5)
1, the ohmic electrode 52 and the lead wire 53) are the evaluation samples 1LA and 1LB (see FIG.
Reference).

Next, a method of manufacturing the evaluation samples 2LA and 2LB for evaluating the lower layer 7a and the upper layer 7b will be described.

In the evaluation sample 2LA, the lower layer 7a
The upper layer 7b is formed by the same method as that of the liquid crystal element 2A described above. In the other evaluation sample 2LB, the lower layer 7a and the upper layer 7b are formed by the liquid crystal element 2 described above.
Formed in the same manner as B. Other manufacturing methods (namely, manufacturing methods of the ITO film 50, the ohmic contact layer 51, the ohmic electrode 52, and the lead wire 53) are the same as those of the evaluation samples 1LA and 1LB in the above-described first embodiment.

Next, a method of evaluating a film using the evaluation samples 2LA and 2LB will be described.

The films (the lower layer 7a and the upper layer 7b) were evaluated by the method shown in FIG. As a result, the impedance polarity ratio Z _ratio was substantially “1” in the evaluation sample 2LA, and was approximately 30 in the evaluation sample 2LB. Accordingly, it was found that the ability of the film (the lower layer 7a and the upper layer 7b) to move charges in and out of the film differs between the sample 2LA and the sample 2LB.

Next, the liquid crystal element 2 prepared by the above-described method is used.
The characteristics of one pixel for A and 2B were examined in the same manner as in Example 1. As a result, in each of the liquid crystal elements 2A and 2B, the asymmetry was 0.3 to 0.4 V and there was no large difference, but the hysteresis was 0.5 V in the liquid crystal element 2A, whereas the hysteresis was 0.5 V in the liquid crystal element 2B. Was significantly inferior to 1.2 V.

[0196] Here, consider the equation _{Z ratio ≦ t / ((ε} L · ρ I) · (d I / d L)).

In the case of this embodiment, t = 10 to 20 μsec
And the film thickness d _I = 4500 ° (element 2A), 4000
Å (element 2B), and the thickness d _L of the liquid crystal layer = 2 μm = 2
0000 °, and the dielectric constant ε _{L of the} liquid crystal is 1 × 10 ^−12.
(The relative dielectric constant is about 10), and the volume resistivity ρ _{I of the} film is
= 1 × 10 ⁷ Ωcm, the right side of the above equation is 4.4 to
8.9 (element 2A) and 5 to 10 (element 2B). In the case of the liquid crystal element 2A, the left side (measured value of Z _ratio ) is 1, which satisfies the above expression, and in the case of the liquid crystal element 2B, the left side (measured value of Z _ratio ) is 30. Not satisfying the above formula. Therefore, according to the present embodiment, when the above equation is satisfied (in the case of the evaluation sample 2LA, that is, in the case of the liquid crystal element 2A), the hysteresis is small, and when the above equation is not satisfied (in the evaluation sample 2LB, that is, the liquid crystal element 2A).
In the case of B), the hysteresis becomes large, and it is understood that the hysteresis is appropriate as long as the above expression is satisfied.

Further, when the liquid crystal element 2A thus produced was driven, the same effect as that of the liquid crystal element 1A in Example 1 was obtained. However, when the other liquid crystal element 2B was driven, the afterimage and the growth and burning of the defective display area were obtained. Some sticking was observed.

On the other hand, the above-mentioned voltage application time margin parameter M2 (= (Δt ₂ −Δt ₁ ) / (Δt ₂ + Δt)
₁ )) is 0.05 when resetting the voltage application of the polarity with the higher impedance side in the liquid crystal element 2B.
Liquid crystal element 2A
In the case of, the voltage was approximately 0.25 equally when resetting either the voltage of the polarity with the larger impedance or the voltage of the polarity with the smaller impedance. In this case, even when a voltage of 20 V is applied between the upper and lower electrodes as the peak value of the driving voltage, no pixel in which the liquid crystal elements 2A and 2B are short-circuited is observed, and the short-circuit prevention function is reduced as a result of margin improvement. There was no trade-off. (Embodiment 3) Further, Embodiment 3 of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

In this embodiment, two types of liquid crystal elements (hereinafter referred to as “liquid crystal element 3A”) differing in the method of forming the non-uniaxial alignment film 7 on the substrate 3 on the non-uniaxial alignment side from the asymmetric configuration shown in FIG. "And" liquid crystal element 3B "), the characteristics of these two types of liquid crystal elements 3A and 3B are compared, and the two types of samples 3LA and 3LB (hereinafter, referred to as the different types) in which the method of forming the film 17 is different. “Evaluation sample 3L
A, 3 LB "), and the film 17 was evaluated.

FIG. 16 is a sectional view showing a specific structure of the liquid crystal elements 3A and 3B produced in this embodiment. As shown in FIG. 16, the liquid crystal elements 3A and 3B It has the same structure as.

Next, a method for manufacturing the liquid crystal element 3A will be described.

First, an ITO film was sputtered on the surfaces of the substrates 2 and 3 using the same apparatus and under the same conditions as those of the first and second embodiments, and the ITO films were patterned to form electrodes 6 and 9. .

Next, the surface of one of the substrates (uniaxially oriented substrate) 2 is coated with a predetermined solution (a nylon solution of 0.2 wt% with formic acid).
Solution) is spin-coated at 3000 rpm for 20 seconds, and baked at 180 ° C. for 60 minutes.
An alignment control film (nylon film) 10 having a thickness of 50 ° was formed. Then, the rotation speed of 1000 r is applied to the orientation control film 10.
pm, pushing amount 0.3mm, feed speed 5mm / s
ec, rubbing treatment was performed three times in one direction.

The other substrate (non-uniaxially oriented substrate) 3
A solution (a solution in which ultrafine particles of SnOx having a particle diameter of about 100 ° are dispersed in a base material in which a polymer of SiOx and a ladder-type polysiloxane are mixed at a ratio of 2: 8). , 1000 rpm, 10 seconds, and baked at 200 ° C. for 60 minutes to give a thickness of 220
A non-uniaxial alignment film 7 of 0 ° was formed.

Further, in the same manner as in Embodiments 1 and 2, S
After the dispersion and fixation of the iO ₂ fine particles and the adhesive particles, the application of the sealant, and the like, the two substrates 2 and 3 were attached to each other, and the liquid crystal was injected.

Next, a method for manufacturing the liquid crystal element 3B will be described.

The electrodes 6 and 9 were formed on the surfaces of the substrates 2 and 3 in the same manner as described above. An orientation control film (polyimide film) 10 was formed on the surface of one substrate (uniaxial orientation side substrate) 2 in the same manner as described above, and the surface of the orientation control film 10 was subjected to a rubbing treatment. .

Furthermore, the other substrate (non-uniaxially oriented substrate)
On the surface of No. 3, a normal RF sputtering apparatus and ZnO (9
Using a target obtained by mixing Al ₂ O ₃ (0.5%) with 5.5%), a non-uniaxially oriented film 7 made of a ZnO film doped with Al was formed to a thickness of 2000 °. The power was 5 W / cm ² and the substrate heating temperature was 200 ° C. Also, a mixed gas of Ar and O ₂ (A
r: 90 SCCM, O ₂ : 10 SCCM), the pressure was 3 mTorr, and the discharge time was 4 minutes.

Further, in the same manner as in Examples 1 and 2, S
After the dispersion and fixation of the iO ₂ fine particles and the adhesive particles, the application of the sealant, and the like, the two substrates 2 and 3 were attached to each other, and the liquid crystal was injected.

Next, a method of manufacturing evaluation samples 3LA and 3LB for evaluating the film 17 will be described.

[0212] The evaluation sample 3LA,
3LB are the evaluation samples 1LA and 1LB of Example 1 (FIG. 1).
2) except for the method of forming the film 17, and the other members (that is, the ITO film 50, the ohmic contact layer 51, the ohmic electrode 52, and the lead wire 53) have the same configuration and the same manufacturing method. That is, the evaluation sample 3L
In A, the film 17 was formed by the same method as in the above-described liquid crystal element 3A, and in the other evaluation sample 3LB, the film 17 was formed by the same method as in the above-described liquid crystal element 3B.

Next, the evaluation of the non-uniaxially oriented film using the evaluation samples 3LA and 3LB will be described.

The evaluation of the non-uniaxially oriented film was performed by the method shown in FIG. As a result, the impedance polarity ratio Z _ratio was substantially “1” in the evaluation sample 3LA, and was approximately 10 in the evaluation sample 3LB. Thus, it was found that the sample 3LA and the sample 3LB differ in the ability of the non-uniaxially oriented film 7 to move charges in and out.

Next, the liquid crystal element 3 prepared by the above-described method is used.
The characteristics of one pixel for A and 3B were examined in the same manner as in Example 1. As a result, the liquid crystal element 3A was 0.1 V and the liquid crystal element 3B was 0.3 to 0.4 V, indicating that the liquid crystal element 3B was slightly inferior. Further, the hysteresis of the liquid crystal element 3A is 0.5 V, while the liquid crystal element 3B has a hysteresis of 0.5 V.
Was inferior to 0.8V.

[0216] Here, consider the equation _{Z ratio ≦ t / ((ε} L · ρ I) · (d I / d L)).

In the case of the present embodiment, the volume resistivity ρ _I of the non-uniaxially oriented film was 3 × 10 ⁷ Ωcm, and the results of the first and second embodiments were not satisfied.
And t = 10 to 20 μsec, d _I = 22
00 ° (element 3A), 2000 ° (element 3B), d _L =
20000 °, ε _L = 1.0 × 10 ⁻¹² . The right side of the above equation is 3 to 6 (element 3A), 3.3 to 6.7 (element 3
B). In the case of the liquid crystal element 3A, the left side (Z
₍ the measured value of _ratio ) is 1, which satisfies the above equation. In the case of the liquid crystal element 3B, the left side (the measured value of Z _ratio ) is 10
However, the above formula is not satisfied. Therefore, according to the present embodiment, when the above expression is satisfied (in the case of the evaluation sample 3LA, that is, in the case of the liquid crystal element 3A), the hysteresis is small. When the above expression is not satisfied (in the evaluation sample 3LB, that is, the liquid crystal element 3B). In the case of), the hysteresis becomes large, and it is understood that the hysteresis is appropriate as long as the above expression is satisfied.

Further, when the liquid crystal element 3A thus produced was driven, the same effect as that of the liquid crystal element 1A in Example 1 was obtained. However, when the other liquid crystal element 3B was driven, the afterimage and the growth or burning of the defective display area were obtained. Some sticking was observed.

On the other hand, the above-described voltage application time margin parameter M2 (= (Δt ₂ −Δt ₁ ) / (Δt ₂ + Δt)
₁ )) In the liquid crystal element 3B, although there was a decrease of 0.05 due to the reset on the side with the larger impedance, the liquid crystal element 3A did not know which side (the side with the larger impedance and the side with the smaller impedance) It was equally about 0.25 for reset. At this time, the peak value of the drive voltage is set at 2 between the electrodes of the upper and lower substrates.
Even when a voltage of 0 V was applied, no pixel in which a short circuit occurred in both of the liquid crystal elements 3A and 3B was observed, and there was no trade-off that a short circuit prevention function was reduced as a result of margin improvement.

[0220]

As described above, according to the present invention,
A pair of substrates arranged at a predetermined distance apart from each other, and a liquid crystal interposed between the pair of substrates, and one of the substrates has a uniaxial alignment characteristic with respect to liquid crystal molecules, and the other substrate In a liquid crystal element having non-uniaxial alignment characteristics with respect to liquid crystal molecules, the substrate having the non-uniaxial alignment characteristics comprises an electrode and a layer provided on the liquid crystal side of the electrode and having different electrical characteristics from the electrode, and The impedance observed by applying a voltage in one thickness direction between the electrode and the layer having different electrical characteristics from the electrode is different from the impedance observed by applying a voltage in the opposite direction,

[0221]

[Formula 7] Z _ratio ≦ t / ((ε _L · ρ _I ) · (d _I / d _L )) Here, Z _ratio ; the electrode and the electrode provided on the liquid crystal side of the electrode and the electrical characteristics. The ratio between the impedance observed when a voltage is applied in the direction of one film thickness to the different layers and the impedance observed when a voltage is applied in the opposite direction ε _L ; dielectric constant t of the liquid crystal; driving the liquid crystal element Basic pulse interval ρ _I ; volume resistivity d _{I of a} layer provided on the liquid crystal side of the electrode and having different electrical characteristics d _I ; different in electrical characteristics from the electrode provided on the liquid crystal side of the electrode By setting the layer thickness d _{L to} the thickness of the liquid crystal, it is possible to reduce the hysteresis and prevent writing failure and burn-in. In addition, after-images can be suppressed, fast responsiveness can be obtained, and flicker and growth of a defective display area can be prevented. Further, it is possible to improve the drive margin while preventing occurrence of a short circuit.

Further, the layer provided on the liquid crystal side of the electrode and having a different electrical property from the electrode has a volume resistivity of 1 × 10 ⁶ to less.
When it is set to 1 × 10 ⁹ Ωcm, occurrence of crosstalk between adjacent pixels can be prevented, and high resolution can be maintained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating one embodiment of a liquid crystal element according to the present invention.

FIG. 2 is a schematic diagram showing the shape and the like of an electrode.

FIG. 3 is an explanatory diagram showing a volume resistance measurement system in a thickness direction of a non-uniaxially oriented film.

FIG. 4 is an explanatory view showing a system for measuring volume resistance in the film surface direction of a non-uniaxially oriented film.

FIG. 5 is a block diagram showing the overall configuration of a liquid crystal display device incorporating a liquid crystal element.

FIG. 6 is a timing chart showing an image information communication state between a liquid crystal element and a graphic controller according to the present invention.

FIG. 7 is a waveform chart showing waveforms of signals applied to electrodes.

FIG. 8 is a schematic diagram showing an example of a display state.

FIG. 9 is a waveform diagram of a drive signal for performing the display shown in FIG.

FIG. 10 shows the relationship between drive voltage and transmittance (ie, V-
FIG.

FIG. 11 is a sectional view showing a specific structure of a sample for evaluation.

FIG. 12 is a schematic view for explaining a method for evaluating a non-uniaxially oriented film.

FIG. 13 is a schematic diagram for explaining a state of examining characteristics of a liquid crystal element.

FIG. 14 is a diagram illustrating hysteresis and switching asymmetry in a liquid crystal element.

FIG. 15 is a cross-sectional view showing a specific structure of the liquid crystal elements 2A and 2B created in Example 2.

FIG. 16 is a cross-sectional view showing a specific structure of the liquid crystal elements 2A and 2B created in Example 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal element 2 Uniaxial alignment side substrate (substrate) 3 Non-uniaxial alignment side substrate (substrate) 5 Liquid crystal 7 Non-uniaxial alignment film 10 Alignment control film (uniaxial alignment film)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Terada 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (11)

[Claims] 1. A liquid crystal device comprising: a pair of substrates disposed at a predetermined distance from each other; and a liquid crystal interposed between the pair of substrates, and one of the substrates has uniaxial alignment characteristics with respect to liquid crystal molecules. In a liquid crystal element, at least one of the pair of substrates includes an electrode and a layer provided on a liquid crystal side of the electrode and having different electric characteristics from each other, and a layer having different electric characteristics from the electrode and the electrode. The impedance observed when a voltage is applied in one thickness direction is different from the impedance observed when a voltage is applied in the opposite direction, and is expressed by the following equation: Z _ratio ≦ t / ((ε _L · ρ _I ) · (d _I / d _L )) Here, Z _ratio : Observed by applying a voltage in the thickness direction to the electrode and a layer provided on the liquid crystal side of the electrode and having different electrical characteristics from the electrode. Impedance by applying a voltage in the opposite direction The ratio of the impedance epsilon _L; liquid crystal dielectric constant t; basic pulse interval [rho _I for driving the liquid crystal element; volume resistivity of the different layers of the electrodes and electrical characteristics provided in the liquid crystal side of the electrode d _I; thickness d _L of the different layers of the electrodes and electrical characteristics provided in the liquid crystal side of the electrode; thickness of the liquid crystal is satisfied, the liquid crystal element, characterized in that. 2. One of the pair of substrates has a uniaxial alignment characteristic with respect to liquid crystal molecules, and the other substrate has a non-uniaxial alignment characteristic with respect to liquid crystal molecules. 2. The liquid crystal element according to claim 1, wherein the substrate has an electrode having the impedance characteristic and a layer having an electric characteristic different from that of the electrode. 3. A layer provided on the liquid crystal side of the electrode and having a different electrical property from that of the electrode has a volume resistivity of 1 × 10 ⁶ to 1 ×.
2. The liquid crystal device according to claim 1, wherein the value is 10 ⁹ Ωcm. 4. A layer provided on the liquid crystal side of the electrode and having different electric characteristics from the electrode is formed of a polycrystalline metal oxide or a polycrystalline semiconductor to which a conductivity control impurity is added. The liquid crystal device according to claim 1. 5. A layer provided on the liquid crystal side of an electrode on the substrate having non-uniaxial alignment characteristics and having different electric characteristics from the electrode by dispersing fine particles in which a conductive control impurity is added into an insulating material. The liquid crystal device according to claim 2, wherein the liquid crystal device is formed by: 6. A chiral liquid containing a fluorine-containing liquid crystal compound having a smectic intermediate phase or a potential smectic intermediate phase, wherein the liquid crystal comprises a fluorocarbon terminal chain and a hydrocarbon terminal chain, both terminal chains being linked by a central nucleus. The liquid crystal element according to claim 1, wherein the liquid crystal element is a smectic liquid crystal. 7. The liquid crystal device according to claim 6, wherein the fluorine-containing liquid crystal compound is represented by the following general formula (I). 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 L ¹ and L ² is 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 X
¹ , Y ¹ and Z ¹ are substituents of A ¹ , A ² and A ³ and independently represent —H, —Cl, —F, —Br, —I, —OH, —O
Represents CH ₃ , —CH ₃ , —CN, or —NO ₂ , and each 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-} (C
_{H 2) ra -N (C pa} H 2pa + 1) represents the -CO-. ra and rb are independently 1 to 20, and pa is 0
~ 4. R ¹ is —O— _{q qa} H _2qa —O—C
_{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 represents _{-O-CO-C qa H 2qa} -R 3, may be either linear, branched (however, R ³ is-
_{O-CO-C qb H 2qb} + 1, -CO-O-C qb H
_{2qb + 1, -H, -Cl,} -F, -CF 3, -N
O ₂ , —CN, and qa and qb independently represent 1 to 20
Is). R ² represents C _xa F _2xa -X (X _is-
H or -F, and xa is an integer of 1 to 20). 8. The liquid crystal device according to claim 6, wherein the fluorine-containing liquid crystal compound is represented by the following general formula (II). Embedded image Represents gb, hb, and ib are each independently an integer of 0 to 3 (however, gb + hb + ib is at least 2)
Represents 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, —C
l, -F, -Br, -I, -OH, -OCH 3, -CH
₃ , —CF ₃ , —O—CF ₃ , —CN, or —NO ₂ , and each of jb, mb, and nb represents an integer of 0 to 4. J ² represents —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—, 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. R ⁴ represents —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, -O-C qc}} H 2qc -R 6, -CO-
O—C _qc H _2qc —R ⁶ , or —O—CO—C _qc H
Represents _2qc -R ^6, linear, may be either branched (wherein, ^{R 6} is _{-O-CO-C qd} H
_{2qd + 1, -CO-O-} C qd H 2qd + 1, -C
_{l, -F, -CF 3, -NO} 2, -CN, or represents -H, qc and qd are independently 1 to 20 integer, the wa 1
-10). R ⁵ is (C _xb F _2xb −
_O) represented by za _-C ya _{F 2ya + 1} (where the formula xb each _{(C xb F} 2xb -O) from 1 to 10 independently, ya is 1 to 10, za is 1
10). 9. The liquid crystal device according to claim 6, wherein the chiral smectic liquid crystal is a liquid crystal exhibiting ferroelectricity. 10. The liquid crystal device according to claim 8, wherein the compound represented by the general formula (II) is a compound comprising a phenylpyrimidine core. 11. The liquid crystal device according to claim 1, wherein the substrate having a uniaxial alignment characteristic has a uniaxial alignment film having a uniaxial alignment characteristic on liquid crystal molecules on a surface thereof.