JPH1114992A - Liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal element which can be driven fast and has high contrast and high luminance. SOLUTION: A film 7 is fold by dispersing a conductive particulate in an insulating base material; and the particulate size of the conductive particulate is 5 to 20 nm and conductive particulate are combined to form a particle mass of 5 to 300 nm in short diameter. The addition rate of the particulate is varied to continuously vary the properties of the film. Further, a deviation voltage ΔV decreases below 3 V, driving control is possible, and there is no deterioration in orientation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a computer terminal display, a word processor, a typewriter,
A liquid crystal element used for a television receiver, a viewfinder of a video camera, a light valve of a projector, a light valve of a liquid crystal printer, and particularly, a liquid crystal exhibiting a chiral smectic phase (a liquid crystal exhibiting ferroelectricity and antiferroelectricity). And a liquid crystal element which displays good display characteristics using a device driven by the action of spontaneous polarization).

[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.

An object of the present invention is to provide a liquid crystal element which can eliminate such a change in threshold value and unstable optical response, can be driven at high speed, and has high contrast and high brightness.

[0019]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a structure in which a liquid crystal is sandwiched between a pair of opposing substrates, and at least one of the substrates has a uniaxial alignment characteristic with respect to liquid crystal molecules. The liquid crystal device shown in the figure, wherein at least one of the pair of substrates is formed by dispersing conductive fine particles in an insulating base material, and the particle diameter of the conductive fine particles is 5 to 20 n.
m, and a plurality of the conductive fine particles are bonded to each other to have a minor axis of 5 to 5.
A 300-nm particle mass is formed and the volume resistivity is 1 ×
A liquid crystal element having a film having a density of 10 ⁵ to 1 × 10 ¹⁰ Ω · cm is provided.

Preferably, in the liquid crystal device of the present invention, at least 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. At least, the substrate having the non-uniaxial orientation characteristic has a film in which the conductive fine particles are dispersed.

[0021]

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

In a liquid crystal device according to one embodiment of the present invention, a liquid crystal is sandwiched between a pair of substrates facing each other, and preferably, one substrate exhibits uniaxial alignment characteristics to liquid crystal molecules, and the other substrate exhibits Having a non-uniaxial alignment film exhibiting non-uniaxial alignment characteristics with respect to liquid crystal molecules (hereinafter, a configuration in which only one substrate exhibits uniaxial alignment characteristics with respect to liquid crystal molecules is referred to as an “asymmetric configuration”). ). The non-uniaxially oriented film is formed by dispersing conductive fine particles in an insulating base material. The conductive fine particles have a particle size of 5 to 20 nm. A particle mass having a diameter of 5 to 300 nm is formed, and the non-uniaxially oriented film has a volume resistivity of 1 × 10 ⁵ to 1 × 10 ¹⁰ Ω · cm. Further, a uniaxial alignment film exhibiting uniaxial alignment characteristics with respect to liquid crystal molecules may be formed on the surface of the one substrate.

FIG. 1 is a sectional view showing an embodiment of the liquid crystal element according to the present invention. The liquid crystal element 1 shown in FIG. 1 includes a pair of substrates 2 and 3 arranged to face each other with a predetermined distance therebetween, and a liquid crystal 5 is sandwiched between the substrates 2 and 3. One of the substrates 2 (hereinafter, referred to as
An electrode 9 is formed on the surface of the “uniaxial alignment side substrate 2”, and a uniaxial alignment film (hereinafter, referred to as an “alignment control film”) exhibiting uniaxial alignment characteristics for liquid crystal molecules so as to cover the electrode 9. 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 illustrated non-uniaxially oriented film 7 is formed. At least, the non-uniaxially oriented film 7 is a film configured by dispersing the above-described conductive fine particles.

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

The uniaxially oriented substrate 2 and the 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 performing a uniaxial orientation process, or may have uniaxial orientation characteristics without such a process.

In the case of the former (which exhibits uniaxial orientation characteristics by performing a predetermined treatment), the material may be an inorganic substance (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) is 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 is exhibited without performing the above-described rubbing treatment.

The thickness of the orientation control film 10 is set to 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.
{}, Particularly preferably 100% or less.

As the alignment control film 10 having uniaxial alignment characteristics, it is particularly preferable to use a polyimide having a structural unit represented by the following formula (P).

[0031]

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

[0032]

Embedded image

[0033]

Embedded image By the way, as the electrodes 6 and 9, ITO (indium) was used.
A transparent conductor such as tin oxide is preferred. Further, as shown in FIG. 2, the electrodes 6 and 9 may be formed in a number of stripes at a constant pitch, and may be formed so that the electrodes 6 and 9 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 (ie, a liquid crystal exhibiting ferroelectricity, a liquid crystal exhibiting antiferroelectricity, or a liquid crystal exhibiting ferroelectricity and antiferroelectricity) is used. Liquid crystal in which the action of spontaneous polarization is applied to driving) is preferable, but a nematic liquid crystal may be used.

When a liquid crystal exhibiting a chiral smectic phase is used, the thickness of the liquid crystal is preferably 5 μm or less from the viewpoint of ensuring bistability.

For example, as a liquid crystal exhibiting a chiral smectic phase (a liquid crystal exhibiting ferroelectricity or a liquid crystal exhibiting antiferroelectricity), a phase transition series isotropic phase → SmA → SmC from high temperature to low temperature. * → It is preferable to use a material that becomes a crystal phase and has a spontaneous polarization of 30 nC / cm ² (at a temperature of about 30 ° C.) and a tilt angle of about 24 degrees.

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 book-shelf structure in which the smectic layer is vertically arranged in parallel with 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 liquid crystal composition containing 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 Things. Such fluorine-containing compounds are specifically described in US Pat.
No. 82,587, U.S. Pat. No. 5,262,082, International Publication WO93 / 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) can be appropriately selected and used.

According to the present embodiment, the liquid crystal element (for example, the mode shown in FIG. 1) has an asymmetric structure in which only one side of one substrate 2 is subjected to uniaxial alignment treatment. The orientation of the (ferroelectric liquid crystal), particularly in the temperature range of SmA, is performed as uniaxial molecular growth from the surface of one of the substrates 2 that has been subjected to the uniaxial orientation treatment,
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. . As the fluorine-containing liquid crystal compound, the terminal portion of the fluorocarbon is -D ¹ -C _xa F _2xa-
Group represented by X, (provided that the formula xa is 1 to 20, X represents -H or -F, D 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 -, - (C
H 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 1-20, and pa is 0-4. ), _{^{Or, -D 2 - (C xb F}} 2xb -O) za -C ya F
A group represented by _{2ya + 1} , wherein xb is independently 1 to 10 for each (C _xb F _2xb -O);
Is 1 to 10, za is 1 to 10, and D ² is
_{-CO-O-C rc H 2rc} , -O-C rc H 2rc -, - C rc H
_{2rc -, - O- (C sa} H 2sa -O) ta -C rd H 2rd -, -
_{O-SO 2 -, - SO} 2 -, - SO 2 -C rc H 2rc -, - C
_rc H _2rc -N (C _pb H _{2pb + 1} ) -SO _2- , -C _rc H _{2rc-
Selected from} N (C _pb H _{2pb + 1} ) —CO— and a single bond;
And rd are each independently 1 to 20; sa is independently 1 to 10 for each (C _sa H _2sa -O);
a is 1 to 6, and pb is 0 to 4. ) Can be used.

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

[0042]

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).

[0049]

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.

[0057]

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[0058]

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[0059]

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[0060]

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[0061]

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[0062]

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[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]

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.

[0069]

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[0070]

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[0071]

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[0072]

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[0073]

Embedded image Further, in the liquid crystal composition, a so-called hydrocarbon type liquid crystal compound having no perfluorocarbon chain can be used. Specific examples include those having the following structures.

[0074]

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[0075]

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[0076]

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[0077]

Embedded image

[0078]

Embedded image Here, the compound represented by the general formula (II) may be a compound comprising a phenylpyrimidine core.

Further, specific examples of the chiral compound include those having the following structures, but the present invention is not limited thereto.

[0080]

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[0081]

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[0082]

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[0083]

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[0084]

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[0085]

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[0086]

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[0087]

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[0088]

[Table 1]

[0089]

[Table 2]

[0090]

[Table 3]

[0091]

[Table 4]

[0092]

[Table 5]

[0093]

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[0094]

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[0095]

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

On the other hand, the non-uniaxially oriented film 7 is formed by dispersing conductive fine particles to which conductive control impurities are added in a base material made of an insulating material. The base material is Si
An oxide melting base material such as Ox, TiOx, ZrOx, or a siloxane polymer may be used.
O, CdO, ZnCdOx Group 12 oxides (group numbers according to IUPAC inorganic chemical nomenclature; the same applies hereinafter), oxides of Ge
O ₂ , SnO ₂ , GeSnOx, TiO ₂ , ZrO ₂ ,
Oxides of Group 4 or 14 elements of TiZrOx, or S
i, a semiconductor of SiC or the like may be used. Further, as the conductivity control impurities, for example, Al, Ga, and In which are Group 13 elements as n-type impurities (donors: impurities that enhance electron conduction) with respect to Group 12 oxides are p-type impurities (acceptors: hole conduction). Cu, Ag, Au, and Li, which are Group 1 and 11 elements, are used as the impurities for enhancing). Also,
P, As, Sb, and Bi, which are Group 15 elements, are used as p-type impurities for Group 4 and 14 oxides as n-type impurities.
Group elements B, Al, Ga, and In are used.

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. I do. 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 10
It can be changed by about 0 mV. When a polycrystalline material is used, it is preferably 1 × 10 ¹⁷ to 1 in consideration of the efficiency of impurity addition.
× 10 ²⁰ / cm ³ (about 0.01% to 1% with respect to the base material) 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.

The non-uniaxially oriented film 7 may be formed by applying a solution in which insulating fine particles and conductive fine particles are dispersed in an organic solvent. Here, general organic solvents may be used, and examples thereof include lower alcohols, ketones, glycols, and ethers. The conductive fine particles have a particle size of 5 to 20 nm.
Are preferred. Further, the insulating fine particles and the conductive fine particles described above are combined with each other while being dispersed in an organic solvent, and the film is formed by appropriately controlling conditions so as to form a particle mass having a diameter of 20 to 300 nm. (Hereinafter, the diameter of the particle mass in the solution is referred to as “the particle mass diameter in the solution”). Note that the optimum range of the particle mass diameter in the solution is different depending on the degree of hydrophilicity of the surface of the insulating fine particles. When the hydrophilicity is strong, the range is preferably 20 to 500 nm, and when the hydrophobicity is strong, 40 to 500 nm. 70 nm is desirable. Further, it is preferable that a plurality of the conductive fine particles be combined even in a state where the film 7 is formed, so as to form a particle lump having a short diameter (hereinafter, referred to as “particle lump diameter”) of 5 to 300 nm.

The volume resistivity of the film 7 is 1 × 10 ⁵
１1 × 10 ¹⁰ Ω · cm.

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

FIG. 3 is a block diagram showing the overall configuration of the liquid crystal display device. As shown in FIG. 3, 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 the drive control circuit 12 to the drive control circuit 411. As shown in FIG. 4, the image information includes scanning line address information and display information. 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 scanning line address information, and the information line driving circuit 405 applies an 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.

On the other hand, as a driving method of the liquid crystal element 1, for example, JP-A-59-193426 and JP-A-59-19
The driving method disclosed in Japanese Patent No. 3427, Japanese Patent Application Laid-Open No. 60-156046, Japanese Patent Application Laid-Open No. 60-156047 or the like may be applied. Hereinafter, a driving method of the liquid crystal element 1 will be described with reference to FIG.

FIG. 5 is a waveform diagram showing the waveform of each signal applied to the electrode. The signal indicated by reference numeral S _S in FIG. 5 shows a selection scan waveform applied to the selected scanning line, a signal indicated by reference numeral S _N is shown a non-selection scanning waveform that is not selected I have. The signal indicated by symbol I _S is
Indicates the selection information signal (black) to be applied to the selected information lines, a signal indicated at I _N is shown 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 a display as shown in FIG. 6 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. 7 is a waveform diagram showing the waveform of the drive signal for performing the display shown in FIG. 6. In order to perform the display shown in FIG. 6, * 3 scanning lines S ₁ and S _{2 are used.} , 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. 5 includes a reset pulse (pulse width t ₁ ) and a write pulse (pulse width t ₂ ), and 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 drive waveform (V _S , V _S
I and Δt) are determined by the switching characteristics of the liquid crystal material used.

FIG. 8 shows the bias ratio V _I / (V _I + V _S )
When the varying drive voltage (V _S + V _I) being kept constant, the relation between the driving voltage (V _S + V _I) and the transmittance T (i.e., V-T characteristic). FIG. here,
Δt = 50 μsec, bias ratio V _I / (V _I + V _S )
Is fixed.

[0112] Then, the right side of Figure 8 prior to display status indicated V-T characteristic in the case of applying the "waveform I _N -S _S (see FIG. 5)" in the 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 and is not retained in white.

[0113] Further, the left side of Figure 8 prior to display status indicated V-T characteristic in the case of applying the "waveform (see FIG. 5) 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 a range of black writing is. 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 .

[0115] Here, V ₃ (hereinafter, referred to as "cross-talk voltage") is, V _B ¹ of the waveform "I _N -S _S" shown in FIG. 5
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.

[0116] 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 becomes 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.

Hereinafter, effects of the present embodiment will be described.

In general, a film on one substrate (for example,
In the structure shown in FIG. 1, when the surface potential of the non-uniaxial alignment film 7) changes from a standard value, a shift occurs in the threshold value of the optical response of the liquid crystal element. The surface potential is determined by the work function and the electron affinity, which are physical properties of the film. Since these physical properties are generally given by the chemical composition of the film, the surface potential is continuously and easily controlled. Difficult to do.

FIG. 9 shows the optical forbidden band width E _gopt , which is a typical parameter of the material, and the addition rate of the conductive fine particles when SnO ₂ is used as the conductive fine particles and SiO ₂ is used as the insulating material. Is expressed using the particle size of the conductive fine particles (SnO ₂ ) as a parameter. According to this figure, the particle size of the conductive fine particles is 5 to 20 nm.
In the range, the optical forbidden band width E _gopt decreases continuously when the addition rate of the fine particles increases, but when the particle diameter of the conductive fine particles is 3 nm smaller than 5 nm, the addition rate of the conductive fine particles is changed. Also, it can be understood that the conductivity characteristic hardly appears, and conversely, if the particle size of the conductive fine particles is larger than 20 nm, the change of the optical bandgap E _gopt becomes discontinuous.

According to the present embodiment, since the particle size of the conductive fine particles is in the range of 5 to 20 nm, the physical properties of the film 7 (optical forbidden band width E _gopt) can be changed by changing the addition rate of the fine particles. Etc.) can be varied continuously.

On the other hand, the conductive fine particles are bonded in the insulating base material to form a lump of the conductive fine particles, and the connection of the conductive fine particles (that is, the contact state between the fine particles and the particle lump diameter). , The resistance value and the surface potential value of the film 7 can be controlled continuously and easily.
That is, even if the content of the conductive fine particles is the same, if the connection of the conductive fine particles is performed firmly and densely, the physical properties of the conductive fine particles appear strongly, and the resistance value of the film 7 can be reduced.
If the connection of the conductive fine particles is weak and sparse, the physical properties of the insulating base material appear, and the resistance value of the film 7 can be increased.

FIG. 10 shows the relationship (VT characteristic) between the voltage and the light transmittance when the voltage applied between the upper and lower electrodes of the liquid crystal element is changed. The difference between the going and returning of the arrow shown in the figure is an amount called hysteresis, and ideally it is desirable to be "0",
In practice, it is sufficient that the driving voltage is about 5% or less. Also,
FIG. 11 is a diagram showing the relationship between the deviation ΔV of the threshold voltage and the particle lump diameter r. As is apparent from this figure, when the particle lump diameter exceeds 300 nm, the deviation voltage ΔV exceeds 3 V. In effect, control as an element cannot be performed. Further, there is also a problem that the unevenness of the surface of the film 7 becomes large, and the alignment of the liquid crystal molecules is deteriorated.

However, according to the present embodiment, the particle mass formed by bonding the conductive fine particles has a diameter of 5 to 300 nm.
And does not exceed 300 nm, the deviation voltage Δ
V becomes 3 V or less, drive control is possible, and there is no problem of deterioration of orientation.

In this embodiment, the film 7 is formed by applying a solution in which insulating fine particles and conductive fine particles are dispersed in an organic solvent. Are formed so as to form a particle mass having a diameter of 20 to 300 nm in a state of being dispersed in an organic solvent, so that the threshold value of the liquid crystal element can be more easily controlled.

According to the present embodiment, a liquid crystal element is obtained in which the reversal electric field generated due to spontaneous polarization Ps and the threshold change, optical instability, etc., caused due to the state of being left untreated are improved. Thus, a liquid crystal element which can be driven at high speed, has high contrast, and has high luminance can be obtained.

[0129]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to specific embodiments. (Embodiment 1) In this embodiment, two types of liquid crystal elements (hereinafter referred to as "liquid crystal element 1A" and "liquid crystal element 1B") having different methods of forming the non-uniaxial alignment film 7 in the element structure shown in FIG. ) To create these two types of liquid crystal elements 1
The characteristics of A and 1B were compared.

First, the structure of 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 each include a uniaxially oriented substrate 2 and a non-uniaxially oriented substrate 3 which are arranged at positions separated by a predetermined distance.
A liquid crystal 5 is sandwiched between these substrates 2 and 3.
Further, an electrode 9 and an alignment control film 10 are formed on the surface of the uniaxial alignment side substrate 2, and the alignment control film 10 is treated to uniaxially align the liquid crystal 5. Further, an electrode 6 and a film 7 are formed on the surface of the non-uniaxial alignment side substrate 3 so as to exhibit 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, a solution obtained by diluting a polyimide of the following structural formula to a concentration of 0.8 wt% with a mixed solution of NMP and nBC (2: 1) was 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. Then, the rotation speed is set to 1000 rpm and the indentation amount is set to 0.4.
rubbing treatment was performed four times in one direction at a feed speed of 10 mm / sec.

[0135]

Embedded image In addition, the surface of the other substrate (non-uniaxially oriented side substrate) 3 has
A solution (a solution in which silicon oxide composed of a polymer of SiOx and ultrafine particles of oxide of SnOx having a particle size of about 10 nm were dispersed in ethanol) was spin-coated at 1000 rpm for 10 seconds. At this time, the solution used had a longer mechanical dispersion time and had a particle mass diameter of about 30 nm in the solution. This was baked at 200 ° C. for 60 minutes to form a film 7 having a thickness of 1500 °.

Next, the orientation 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, Trepearl particles (Toray, particle size about 5μ)
The solution containing the adhesive particles (m) was applied by a spin coating method, and heated again to disperse and fix the trepearl particles.

Further, using a printing machine, a sealant is applied to a desired position of the substrate 3 on the non-uniaxial processing side.
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 in the above operation is placed in a normal load-lock type vacuum chamber, and the empty element is placed in a 1 × 10 5
^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 coated with the same solution as the liquid crystal element 1A (silicon oxide made of a polymer of SiOx and Sn having a particle size of about 10 nm).
A solution of Ox oxide ultrafine particles dispersed in ethanol) was spin-coated at 1000 rpm for 10 seconds. At this time, since the mechanical dispersion time of the solution was set as a standard, the particle mass diameter in the solution was about 60 nm. This is 2
The resultant was baked at 00 ° C. for 60 minutes to form a film 7 having a thickness of 1500 °.

Further, in the same manner as described above, after dispersing and fixing the SiO ₂ fine particles and trepearl particles, applying a sealing agent, and the like, the two substrates 2 and 3 are bonded together.
Liquid crystal injection was performed.

The resistance value (volume resistance) of the film was measured for the other substrate (non-uniaxially oriented substrate) in the device (actually, a sample for measurement was separately prepared and measured).

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

FIG. 12 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 of Al having a diameter of 1 mmφ, and the other electrode 22 is an electrode of ITO.

FIG. 13 is a diagram showing a system for measuring the resistance value of the film in the film surface direction.
Is a film to be measured, and a current is applied between the electrode 25 and the electrode 26 to perform measurement.

According to the present embodiment, the sheet resistance of the film 7 in the liquid crystal element 1A was about 3 × 10 ¹¹ Ω / □ and the volume resistivity was 5 × 10 ⁶ Ω · cm, whereas the liquid crystal element 1A 1B
The sheet resistance of the film 7 is about 3 × 10 ¹⁰ Ω / □, the volume resistivity is 5 × 10 ⁵ Ω · cm, and the latter has lower resistance than the former, and has an electrical separation capability between adjacent pixels. Was inferior.

The asymmetry of the VT characteristic (ie,
The deviation of the threshold voltage ΔV) is about 0.3 to less for the liquid crystal element 1A.
While the value was as small as 0.4 V, the liquid crystal element 1B was as large as 1.5 V, which caused a large problem in driving.

Further, when the produced liquid crystal element 1A is driven, no flickering or growth of a defective display area is observed, and extremely good bistability is obtained, and burn-in and progress of monostability are sufficiently suppressed. It was confirmed.

On the other hand, when the other liquid crystal element 1B was driven, some afterimages and growth and burn-in of a defective display area were observed. Embodiment 2 In this embodiment, two types of liquid crystal elements (hereinafter, “liquid crystal element 2A” and “liquid crystal element 2B”) differing in the method of forming the non-uniaxial alignment film 7 in the element structure shown in FIG. To) was created.

In the liquid crystal element 2A, a solution in which ladder-type polysiloxane and SnOx oxide ultrafine particles having a particle diameter of about 10 nm are dispersed in ethanol is used as a solution for forming the film 7. And add this solution to 10
Spin coating was performed under the conditions of 00 rpm and 10 seconds. At this time, the solution used had a longer mechanical dispersion time and had a particle mass of about 40 nm in the solution. After spin coating, baking is performed at 200 ° C. for 60 minutes so that the film 7 has a thickness of 250
0 °. The other configuration and the manufacturing method were the same as those in the first embodiment.

In the other liquid crystal element 2B, as a solution for forming the film 7, the same solution as the liquid crystal element 2A (ladder-type polysiloxane and SnO having a particle diameter of about 10 nm) was used.
a solution in which x-oxide ultrafine particles are dispersed in ethanol)
This solution was spin-coated at 1500 rpm for 10 seconds. At this time, since the mechanical dispersion time of the solution was set as a standard, the particle mass diameter in the solution was about 60 nm. After the spin coating, the coating was baked at 200 ° C. for 60 minutes to make the thickness of the film 7 2500 °. The other configuration and the manufacturing method were the same as those in the first embodiment.

The resistance of the film 7 on the non-uniaxially oriented substrate in the device of this example was evaluated. The sheet resistance of the film 7 in the liquid crystal element 2A was about 3 × 10 ¹² Ω / □ and the volume resistivity was 7.5 × 10 ⁷ Ω · cm, whereas the sheet resistance of the film 7 in the liquid crystal element 2B was About 3 × 10 ⁹ Ω
/ □, the volume resistivity is 7.5 × 10 ⁴ Ω · cm,
It can be understood that the latter has lower resistance than the former, and is inferior in the electrical separation ability between adjacent pixels.

Also, the asymmetry of the VT characteristic (ie,
The threshold voltage deviation ΔV) is about 0 to 0.1 for the liquid crystal element 2A.
V and the voltage of the liquid crystal element 2B was 0.4 to 0.5 V, and no major problem occurred in driving.

Further, when the liquid crystal element 2A thus produced was driven, no flickering or growth of a defective display area was observed, and a very high-definition image could be realized.

On the other hand, when the other liquid crystal element 2B was driven, a short circuit occurred between adjacent lines, and display was disabled for each line, deteriorating display quality.

[0158]

According to the present invention, the non-uniaxially oriented film is formed by dispersing conductive fine particles having a particle size of 5 to 20 nm in an insulating base material. By doing so, the physical properties of the non-uniaxially oriented film can be changed continuously.

Further, since the conductive fine particles are bonded in the insulating base material to form a particle mass by the conductive fine particles, the way of connecting the conductive fine particles (that is, the state of contact between the fine particles). And the particle mass diameter), the resistance value and the surface potential value can be controlled continuously and easily. In particular, according to the present invention, the minor axis of the particle mass formed by bonding the conductive fine particles is in the range of 5 to 300 nm and does not exceed 300 nm.
In the following, drive control is possible, and there is no problem of deterioration of orientation.

Further, according to the present invention, it is possible to obtain a liquid crystal element in which the reversal electric field generated due to the spontaneous polarization Ps and the threshold change, optical instability, etc., which are generated due to the state of being left unattended are improved. Thus, a liquid crystal element which can be driven at high speed, has high contrast, and has high luminance can be obtained.

Further, according to the present invention, it is possible to reduce the hysteresis and prevent the writing failure and the 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.

[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 a block diagram showing the overall configuration of a liquid crystal display device incorporating a liquid crystal element.

FIG. 4 is a timing chart showing an image information communication state between the liquid crystal element and the graphic controller according to the present invention.

FIG. 5 is a waveform chart showing waveforms of signals applied to electrodes.

FIG. 6 is a schematic diagram showing an example of a display state.

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

FIG. 8 shows the relationship between drive voltage and transmittance (ie, VT
FIG.

FIG. 9 is a graph showing the relationship between the addition rate of conductive fine particles and the optical bandgap _Egopt .

FIG. 10 is a diagram illustrating hysteresis and the like in a liquid crystal element.

FIG. 11 is a diagram showing a relationship between a diameter of a particle mass formed of conductive fine particles and a deviation voltage.

FIG. 12 is an explanatory diagram showing a volume resistance measurement system in a film thickness direction.

FIG. 13 is an explanatory view showing a volume resistance measurement system in a film surface direction.

[Description of Signs] 1 Liquid crystal element 2 Uniaxial alignment side substrate 3 Non-uniaxial alignment side substrate 5 Liquid crystal 7 Non-uniaxial alignment film 10 Alignment control film (uniaxial alignment film)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G02F 1/141 G02F 1/137 510

Claims (6)

[Claims] A liquid crystal is sandwiched between a pair of opposed substrates,
At least one of the substrates is a liquid crystal element exhibiting uniaxial alignment characteristics with respect to liquid crystal molecules, and at least one of the pair of substrates is formed by dispersing conductive fine particles in an insulating base material; The fine particles have a particle size of 5 to 20 nm, a plurality of the conductive fine particles are combined to form a particle mass having a short diameter of 5 to 300 nm, and the volume resistivity is 1 × 10 ⁵ to 1 × 10 ^10.
A liquid crystal element having a film of Ω · cm. 2. One of the 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 device according to claim 1, comprising a film in which conductive fine particles are dispersed. 3. The liquid crystal device according to claim 1, wherein the one substrate has a uniaxial alignment film exhibiting a uniaxial alignment characteristic with respect to liquid crystal molecules. 4. 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. 5. The liquid crystal device according to claim 4, 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). 6. The liquid crystal device according to claim 4, 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).