JP3413429B2 - Manufacturing method of liquid crystal element - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally widely used liquid crystal display devices include, for example, M. Schad.
t) and W. Helfrich
h) By Applied Physics Letter
s Volume 18, Issue 4 (Published February 15, 1971) No. 1
Those using twisted nematic liquid crystals shown on pages 27 to 128 are known. Further, a simple matrix type liquid crystal element is known as a typical liquid crystal element. This type has an advantage in terms of cost because it is easy to manufacture an element. However, the number of pixels is limited because of the problem that crosstalk occurs during time-divisional driving using a matrix electrode structure having a high pixel density. Also, since the response speed is as slow as 10 milliseconds or more,
Its use as a display was limited. In recent years, liquid crystal elements called TFTs have been developed for such simple matrix type elements. Since this type creates a transistor in each pixel, problems of crosstalk and response speed are solved, but it is very difficult to create a liquid crystal element without defective pixels as the area increases. In addition, even if possible, a great cost is incurred.

In order to improve the drawbacks of the conventional liquid crystal device, a device using a liquid crystal in which the liquid crystal has bistability is disclosed by Clark and Laguwell.
erwall) (JP-A-56-1)
07216, U.S. Pat. No. 4,367,924). As the liquid crystal exhibiting this bistability, a ferroelectric liquid crystal having a chiral smectic C phase is generally used. Since this ferroelectric liquid crystal undergoes inversion switching by spontaneous polarization, it is possible to obtain a very fast response speed and to develop a bistable state having a memory property. Further, since it has excellent viewing angle characteristics, it is considered to be suitable as a high-speed, high-definition, large-area display element or light valve.

In such a chiral smectic liquid crystal element, the liquid crystal has a zigzag shape as described in, for example, "Structure and Physical Properties of Ferroelectric Liquid Crystal" (Corona Publishing Co., Atsuo Fukuda, Hideo Takezoe, 1990). Causes alignment defects,
There is a problem that the contrast is significantly reduced.
The defect is that the smectic layered structure of the chiral smectic liquid crystal supported between the upper and lower substrates forms two types of chevron structures having different bending directions. Furthermore, the bending angle of the smectic layer structure (based on the substrate normal) It is believed that this occurs because the layer inclination angle δ) is quite large. Recently, by eliminating the chevron structure having such a defect, a layered structure called a bookshelf, that is, a structure in which a smectic liquid crystal layer is substantially perpendicular to the substrate, or a structure close to it, has been revealed, and high contrast There is a movement to realize a new liquid crystal element.

For example, as a liquid crystal material exhibiting a structure of a bookshelf or a structure similar thereto, for example, a liquid crystal compound having a perfluoroether side chain (US Pat. No. 5,262,562).
082, International Application Patents WO93 / 22396, 1993
4th International Conference on Ferroelectric Liquid Crystals P-46, Marc D. et al.
Radcliffe et al.) Is disclosed. This liquid crystal can exhibit a smectic layer structure having a small layer tilt angle close to a bookshelf due to the characteristics of the material itself.

[0006]

However, according to the detailed observations made by the present inventors, the size of the tilt angle δ of the smectic layer is determined by the temperature characteristic of the size of the layer spacing, that is, the width of each smectic layer. Inevitably produced by, and has a finite value that is not zero even if it is a few degrees or less, if the orientation control is not sufficiently accurate,
Although the zigzag defects due to the chevron structure described above are often not clearly seen, defects and disclination lines due to the discontinuity of the layer structure are also found due to the presence of the bent smectic layer. When a liquid crystal device having this liquid crystal alignment property is used as a display of a simple matrix drive system, an information signal similar to the AC signal that is continuously applied causes the above-mentioned defects, inversion domains of liquid crystal molecules generated from disclination lines, and An increase in the degree of molecular fluctuations on the switching cone occurs. For this reason, phenomena such as a small driving margin and a sharp decrease in contrast during driving have occurred.

The present invention has been made in view of the above problems, and an object of the present invention is to realize a high contrast, a large driving margin, and a liquid crystal element in which a decrease in the contrast during driving is suppressed, particularly A liquid crystal device using a chiral smectic liquid crystal, a liquid crystal exhibiting ferroelectricity, and a liquid crystal device using the device.

[0008]

The above object of the present invention is solved by the following first and second inventions.

That is, the first aspect of the present invention is a method for producing a liquid crystal element in which a liquid crystal exhibiting a smectic phase is sandwiched between a pair of substrates provided with electrodes. The liquid crystal is heated to an isotropic liquid.
Then, by cooling to room temperature without applying an electric field,
The liquid crystal portion is composed of a plurality of smectic liquid crystal layers, in the liquid crystal portion, the smectic liquid crystal layer,
A region existing in a chevron shape with an inclination angle corresponding to the value of the inclination angle with respect to the substrate normal, which is calculated based on the temperature characteristic of the layer spacing of the liquid crystal layer, and the smectic liquid crystal layer, It is a method of manufacturing a liquid crystal element, characterized in that a region having an inclination angle smaller than a value of an inclination angle with respect to a substrate normal calculated based on temperature characteristics is mixed.

A second aspect of the present invention is a method for producing a liquid crystal element in which a liquid crystal exhibiting a smectic phase is sandwiched between a pair of substrates provided with electrodes. The liquid crystal is heated to an isotropic liquid,
Cool down to room temperature while applying an electric field in the Mectic A phase
In other words, the liquid crystal part is composed of a plurality of smectic liquid crystal layers, and in the liquid crystal part, the smectic liquid crystal layer has a tilt angle with respect to the substrate normal line calculated based on the temperature characteristic of the layer spacing of the liquid crystal layer. The region existing in a chevron shape with an inclination angle corresponding to the value of and the smectic liquid crystal layer has a smaller inclination than the value of the inclination angle with respect to the substrate normal calculated based on the temperature characteristics of the layer spacing of the liquid crystal layer. A method for manufacturing a liquid crystal element, characterized in that regions having corners are mixed.

[0011]

[0012]

Further, according to the present invention, there is provided a liquid crystal device comprising the above-mentioned first to fourth liquid crystal elements and means for driving the elements.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystal element of the present invention is obtained by appropriately controlling the materials, prescriptions, manufacturing and processing conditions of members such as liquid crystal and film forming the element, and the external processing of the element. Liquid crystal enclosed in the element (cell),
In particular, in a chiral smectic liquid crystal (chiral smectic phase), a smectic layer composed of liquid crystal molecules (smectic liquid crystal layer) is present in a chevron-like region with a tilt angle of a predetermined finite value with respect to the substrate normal line. The layers are calculated based on the temperature characteristics of the layer spacing of the liquid crystal layer. By making the area where the tilt angle is smaller than the value of the tilt angle with respect to the substrate normal, or the area where the smectic layer is present in the so-called bookshelf shape in the direction perpendicular to the substrate, to clearly exist, It is possible to improve the display characteristics by reducing the number of alignment defects, obtaining a good alignment state with high accuracy and realizing high contrast, and improving the driving margin and the like.

The tilt angle, which is one of the most characteristic requirements of the liquid crystal device of the present invention, usually corresponds to the angle at which the smectic layer is actually tilted with respect to the substrate normal in the device.

The tilt angle is basically determined by the method disclosed by Clark and Lagawell (Japan Display 86) 198.
6, pp456-458) and is a value measured and defined by the X-ray measurement method.

In particular, in the first, second and fourth liquid crystal elements of the present invention, the layer spacing (width of the smectic liquid crystal layer) with respect to the actual tilt angle of the smectic layer in the chiral smectic phase described above. The value of the tilt angle calculated based on the temperature characteristic of the size), that is, the change in the layer spacing with temperature, is set, and the tilt angle of the former has a specific relationship with the calculated tilt angle of the latter. By controlling the existence of the region having such a layer structure, excellent device characteristics are obtained.

The value of the inclination angle (δ) with respect to the substrate normal, which is calculated based on the temperature characteristics of the layer spacing of the smectic layer, undergoes a phase transition such as SmA → SmC ^(*) especially under cooling. In the case of a chiral smectic liquid crystal, δ = cos ⁻¹ (dc / d _TCA ) d _C : layer spacing of the smectic layer at the temperature (measurement temperature) d _TCA : SmA → SmC ^(*) smectic at the phase transition temperature Given by the layer spacing of the layers.

The "chevron (structure)" of the smectic layer composed of liquid crystal molecules defined in the first to fourth aspects of the present invention means that each smectic liquid crystal layer is near the midpoint between a pair of substrates of a liquid crystal element. The angle of inclination (measured value) with respect to the normal to the substrate of the layer described above is substantially about 3
It has a structure larger than that. Further, in particular, a chevron having a tilt angle "corresponding" to the value of the tilt angle with respect to the substrate normal, which is calculated based on the temperature characteristic of the layer spacing of the smectic liquid crystal layer, which is defined in the second and fourth aspects of the present invention. The shape is the range of the error (measurement error of the layer spacing or the error caused by the calculation error) of the value of the layer inclination angle calculated based on the temperature characteristics of the layer spacing above the inclination angle (measured value) of the smectic liquid crystal layer. More specifically, the structure is such that it is within a range of at least ± 20% of the value of the layer inclination angle calculated above.

On the other hand, the first and second aspects of the present invention,
The chevron shape that has a "smaller" tilt angle than the tilt angle value with respect to the substrate normal calculated based on the temperature characteristics of the layer spacing of the smectic liquid crystal layer is the tilt angle of the smectic liquid crystal layer (measured value) Is a small value outside the error of the value of the layer inclination angle calculated based on the temperature characteristic of the layer spacing (measurement error of the layer spacing or the error caused by the calculation error), more specifically at least the above calculation. The structure is such that it is smaller than 80% of the value of the layer inclination angle due to.

The regions in which the smectic liquid crystal layers are present in a "bookshelf shape in a direction substantially perpendicular to the substrate" defined in the third and fourth aspects of the present invention are the respective smectic liquid crystal layers. Is a region in which it is substantially vertical without being bent in the direction perpendicular to the pair of substrates, and a pseudo bookshelf structure in which the tilt angle (measured value) of the liquid crystal layer is 3 degrees or less is used. Also includes. Further, it corresponds to a region having a structure of the liquid crystal layer in which the tilt angle (measured value) of the smectic liquid crystal layer is at least smaller than 80% of the value of the layer tilt angle calculated above.

In the liquid crystal element of the present invention, particularly the first and second liquid crystal elements, the smectic liquid crystal layer has a value of an inclination angle with respect to the substrate normal calculated based on the temperature characteristic of the layer spacing of the liquid crystal layer. The area existing with a smaller inclination angle is 10% in terms of the area ratio in the effective optical modulation area of the device.
Above all, it is preferable that 40% or more is present in order to effectively improve the alignment state in the entire device and to improve the contrast and the driving margin.

Further, in the liquid crystal device of the present invention, particularly in the third and fourth liquid crystal devices, the area where the smectic liquid crystal layer exists in a bookshelf shape in the direction perpendicular to the substrate is an effective optical modulation area of the device. 10% or more in terms of area ratio, especially 4
It is preferably present at 0% or more.

Further, in the liquid crystal device of the present invention, in the region where the smectic liquid crystal layer exists in the chevron shape, the tilt angle of the smectic liquid crystal layer with respect to the substrate normal is 7
It is preferably not more than °.

Further, in the liquid crystal element of the present invention, preferably, the liquid crystal portion is set to a temperature range in which it exhibits a smectic A phase (for example, a liquid crystal in a temperature range in which an isotropic phase is present between a pair of substrates). And then slowly cooling, or by setting the temperature range in which the order is higher than the smectic A phase to exhibit the smectic A phase), or by applying an electric field from the outside, the substrate normal to the smectic layer is applied. It is possible to increase the ratio of the region where the inclination angle is relatively small to the region where the smectic liquid crystal layer is present in the bookshelf shape in the direction perpendicular to the substrate, particularly to 40% or more. . That is, the layer structure can be controlled by applying an electric field in the smectic A phase.

The above-mentioned method utilizes the electric field application in the smectic A phase in which the spontaneous polarization does not appear in the liquid crystal element, and the electroclinic effect caused by the electric field application in the smectic A phase effectively works. Is expected to be.

The voltage application in the above-mentioned smectic A phase is preferably performed at least on the low temperature side of the temperature range showing the smectic A phase of the liquid crystal composition, at least at the Tac point (smectic A phase).
It is carried out for 1 minute or more within a predetermined temperature range (1 ° C or more and the entire temperature range width of the smectic A phase) including a range 5 ° C higher than the phase-transition temperature of the chiral smectic C phase). The voltage condition is
Preferably, the voltage is set to 5 V or more and the frequency is set within a relatively low frequency range up to 1 kHz.

An example of the structure of the liquid crystal device of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an example of the liquid crystal element of the present invention.
1 is preferably a liquid crystal moiety composed of a chiral smectic liquid crystal composition, and preferably, in order to realize bistability according to the Clark and Lagawell model described above,
The layer thickness (distance between substrates) is preferably 5 μm or less. Reference numeral 2 denotes a substrate, which is made of a highly transparent material such as glass or plastic. Reference numeral 3 is a transparent electrode made of a transparent conductive material such as ITO for applying a voltage to the liquid crystal 1.

Reference numeral 4 is an alignment control layer which affects the alignment state of the liquid crystal. Examples of the material of the orientation control layer include silicon monoxide, silicon dioxide, aluminum oxide, zirconia,
Magnesium fluoride, cerium oxide, cerium fluoride,
Silicon nitride, silicon carbide, inorganic substances such as boron nitride, polyvinyl alcohol, polyimide, polyimide amide, polyester, polyamide, polyester imide, polyparaxylene, polycarbonate, polyvinyl acetal, polyvinyl chloride, polystyrene,
Organic substances such as polysiloxane, cellulose resin, melamine resin, urea resin, and acrylic resin can be used. With respect to such an orientation control layer, it is preferable to perform uniaxial orientation treatment on the layer provided on at least one of the substrates. The orientation control layer subjected to the uniaxial orientation treatment is formed, for example, by coating the above-mentioned organic or inorganic material on the substrate or on a predetermined layer by solution coating, vapor deposition, sputtering or the like, and then velveting the coating surface. Rubbing with fibrous material such as cloth or paper
It is obtained by doing. It is also possible to form an uniaxially oriented layer by adopting an oblique evaporation method in which an oxide such as SiO or a nitride is obliquely evaporated. 41 The thickness of the orientation control layer is preferably 200 Å or less from the viewpoint of suppressing the magnitude of the counter electric field generated by switching of the spontaneous polarization Ps and having good switching performance. When it is 100 Å or less, it may be more preferable.

In the present invention, it is preferable to use elements having different alignment treatments on the respective substrates, depending on the liquid crystal material used. For the liquid crystal composition used in the liquid crystal element of the present invention, a material having no cholesteric phase may be selected in order to control the tilt angle of the smectic layer as described above. In such a case, an isotropic phase of the liquid crystal substance-a smectic phase transition to form an alignment state while gradually generating a baddone, but one of the substrates begins to generate a baddone,
From the viewpoint that it appears to grow to the other substrate side and it is easy to achieve good uniform alignment, it is preferable that both substrates have different alignment treatments on the alignment film, and more preferably one substrate is uniaxial. A structure is used in which an alignment film having an alignment treatment is provided, and an alignment control layer having a different treatment, for example, a layer having no uniaxial alignment property, is provided on the other substrate. When a chiral smectic liquid crystal composition as described below is used in an element having the following asymmetric alignment film structure having a polyimide alignment control film subjected to uniaxial alignment treatment, it has good driving characteristics in a very wide temperature range, and particularly It is possible to obtain an element having a good bistable state and having high reliability and driving stability.

In the present invention, as an alignment film on at least one of the substrates, from the viewpoint of alignment control characteristics,
As a specific structure of the material preferably used, there can be mentioned a polyimide having a repeating unit represented by the following general formula P. Here, when adopting a configuration of performing different orientation treatment on both substrates, the polyimide orientation control layer is preferably provided by uniaxial orientation treatment, on the opposite side, for example, in the base material from the viewpoint of orientation controllability. A film in which fine oxide particles are dispersed is used.

[0033] [Formula P] ^{(-K-P 11 -L 11 -M} 11 - (L 12) a -P 12
−)

[0034]

[Outside 5] And L ¹¹ and L ¹² are independent of each other.

[0035]

[Outside 6] Or represents an alkylene group having 1 to 20 carbon atoms, P
¹¹ and P ²² represent an imide bond. M ¹¹ represents a single bond or —O—, and a represents 0, 1, 2. )

Specific structures of these polyimides include, for example, the following repeating unit structures.

[0037]

[Outside 7]

[0038]

[Outside 8]

[0039]

[Outside 9]

As the orientation control layer on at least one of the substrates, for example, an insulating polymer film or ultrafine particles such as oxides to which a conductivity control impurity is added if necessary is dispersed in the base material. A film of a material made of Specifically, ZnO, CdO, ZnCd
Group II element oxides such as Ox, GeO2, SnO2, G
I such as eSnOx, TiO2, ZrO2, TiZrOx
Ultrafine particles of oxides such as oxides of Group V elements, to which conductivity controlling impurities are added as needed, are used. Here, as the conductivity controlling impurities, for example, for a group II oxide, a group III element B as an n-type impurity,
Examples of the p-type impurities include Al, Ga and In, and group I elements such as Cu, Ag, Au and Li. Further, P, As, which is a group V element, as an n-type impurity for the group IV oxide,
Sb and Bi include B, Al, Ga, and In, which are group III elements, as p-type impurities. Particularly preferably,
A coating type film is used in which ultrafine particles of SnO2 doped with impurities such as Sb are dispersed in a base material such as silica or siloxane polymer.

In the liquid crystal device of the present invention, depending on the alignment characteristics of the liquid crystal material used, one of the substrates, which is uniaxially oriented with the film made of the above-mentioned organic material such as polyimide, is used as the orientation control layer, and the other is used. In the substrate, a film (coating film) in which the above-mentioned ultrafine oxide particles are dispersed in the base material can be used.

Further, in addition to the above orientation control layer, an insulating layer as a short-circuit preventing layer of the pair of substrates, another organic material layer, or an inorganic material layer may be formed. Reference numeral 5 is a gap control spacer, for example, silica beads or the like is used. 8
Is a polarizing plate, and 9 is a light source. Switching is performed in response to a switching signal from a signal power source (not shown), and it functions as a light valve of the display element. Further, if the three transparent electrodes are arranged in a matrix in the upper and lower crosses, pattern display and pattern exposure become possible. For example, a display of a personal computer, a workstation or the like,
Used as a light valve for printers.

In the liquid crystal device of the present invention, as a liquid crystal portion (liquid crystal 1 in the structure shown in FIG. 1) disposed between a pair of substrates, particularly a chiral smectic liquid crystal or a liquid crystal exhibiting ferroelectricity, preferably a fluorocarbon terminal chain. A fluorine-containing liquid crystalline compound having a smectic mesophase or a latent smectic mesophase, which is composed of a (moiety) and a hydrocarbon chain (moiety), and has both end chains (moiety) bound by a central nucleus. A chiral smectic liquid crystal composition containing a seed is used.

As used herein, a compound having a latent smectic intermediate layer does not represent a smectic intermediate layer by itself, but in a mixture with a compound having a smectic intermediate layer or a compound having another latent smectic intermediate layer, A compound that develops a smectic intermediate layer under appropriate conditions.

In the structure of the above-mentioned fluorine-containing liquid crystalline compound used as the main component of the liquid crystal composition in the liquid crystal device of the present invention, the central nucleus generally has at least two aromatic rings, aliphatic rings or substituted aromatic rings. A ring or a substituted heteroaromatic ring, and these rings are mutually --COO--, --COS.
They may be bound by a functional group selected from the group consisting of-, -HC = N-, and -COSe-. These rings may be fused or non-fused. The heteroatom in the heteroaromatic ring contains at least one atom selected from N, O or S. Non-adjacent methylene groups in the aliphatic ring may be replaced by O.

In the fluorine-containing liquid crystal compound, the fluorocarbon terminal portion is a group represented by -D ¹ -C _xa F _2xa -X (where xa is 1 to 20, X
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
Are independently 1 to 20, and pa is 0 to 4. Or a group represented by -D ^2- (C _xb F _2xb -O) _za -C _ya F _{2ya + 1} , (where xb is the respective (C _xb
F _2xb —O) is independently 1 to 10, and ya is 1 to 1
0, za is 1 to 10, 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 single bonds, rc and rd
Are independently 1 to 20, and sa is (C _sa H
_2sa- O) is independently 1 to 10, ta 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.

[0048]

[Outside 10] 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 --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 to 4.

J ¹ is --CO--O-(CH ₂ ) _ra- , <sub>--O
- (CH 2) ra -,</sub> - (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} ) -CO-. ra and rb are independently 1
~ 20 and pa is 0-4.

R ¹ is --O--C _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, linear, it may be either branched (wherein, 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]

[Outside 11] Represents

Gb, hb and ib are independently 0 to 3
(Wherein 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 represents -O-.

Each of X ² , Y ² and Z ² is a substituent of A ⁴ , A ⁵ and A ⁶ , and independently --H, --Cl, --F, --Br,-.
_{I, -OH, -OCH 3, -CH} 3, -CF 3, -O-C
F _3, -CN, or represents -NO _2, each jb, m
b and nb each independently represent an integer of 0-4.

[0059] 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-
, Rc and rd are independently 1 to 20, sa is independently 1 to 10 for each (C _sa H _2sa —O), ta is 1 to 6, and pb is 0 to 4. is there.

[0060] 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, -O-}} C qc H 2qc -R 6, -CO-O-C
_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
-10 and za is 1-10).

The compound represented by the above general formula (I) is
Japanese Unexamined Patent Publication No. 2-142753, US Pat.
It can be obtained by the method described in No. 2,587.
Specific examples of such compounds are listed below.

[0063]

[Outside 12]

[0064]

[Outside 13]

[0065]

[Outside 14]

[0066]

[Outside 15]

[0067]

[Outside 16]

[0068]

[Outside 17]

[0069]

[Outside 18]

[0070]

[Outside 19]

[0071]

[Outside 20]

[0072]

[Outside 21]

[0073]

[Outside 22]

[0074]

[Outside 23]

The compounds represented by the above general formula (II) are described in International Publication WO93 / 22396, Japanese Patent Publication No. 7-506.
It can be obtained by the method described in Japanese Patent No. 368.
Specific examples of such compounds are listed below.

[0076]

[Outside 24]

[0077]

[Outside 25]

[0078]

[Outside 26]

[0079]

[Outside 27]

[0080]

[Outside 28]

In the liquid crystal composition used in the liquid crystal device of the present invention, a so-called hydrocarbon type liquid crystalline compound having no fluorocarbon chain can be blended in addition to the above-mentioned fluorine-containing liquid crystalline compound.

In the chiral smectic liquid crystal composition used in the present invention, it is essential to blend at least one kind of optically active compound. Such an optically active compound can be selected from compounds having a linear or cyclic optically active site in consideration of compatibility with other liquid crystal components such as the above-mentioned fluorine-containing liquid crystalline compound.

Specific examples of the hydrocarbon type liquid crystalline compound that can be used in the present invention are listed below.

[0084]

[Outside 29]

[0085]

[Outside 30]

[0086]

[Outside 31]

[0087]

[Outside 32]

[0088]

[Outside 33]

[0089]

[Outside 34]

[0090]

[Outside 35]

[0091]

[Outside 36]

[0092]

[Outside 37]

[0093]

[Outside 38]

[0094]

[Outside 39]

[0095]

[Outside 40]

[0096]

[Outside 41]

[0097]

[Outside 42]

[0098]

[Outside 43] In the liquid crystal composition used in the present invention, it is essential to add at least one kind of optically active compound (chiral compound) as described above.

Specific examples of such a chiral compound include those having the following structures.

[0100] ^{(a4) R 6 "-A 6} " -X 6 "-A 7" -
A ⁸ "-X ⁷ " -R ⁷ "-Σ ^**- R ⁹ "

[0101]

[Table 1]

[0102]

[Table 2]

[0103]

[Table 3]

[0104]

[Table 4]

[0105]

[Table 5]

* Abbreviations in a4 Abbreviations used in Table A are as follows.

[0107]

[Outside 44]

[0108]

[Outside 45]

[0109]

[Table 6]

[0110]

[Table 7]

[0111]

[Table 8]

[0112]

[Table 9]

[0113]

[Table 10]

* Abbreviations in a5 The abbreviations used in Table B are as follows.

[0115]

[Outside 46]

[0116]

[Outside 47]

[0117]

[Outside 48]

[0118]

[Outside 49]

[0119]

[Outside 50] D-1: n = 6,2R, 5R D-2: n = 6,2S, 5R D-3: n = 4,2R, 5R D-4: n = 4,2S, 5R D-5: n = 3,2R, 5R D-6: n = 2,2S, 5R D-7: n = 2,2R, 5R D-8: n = 1,2S, 5R D-9: n = 1,2R, 5R

[0120]

[Outside 51] D-10: n = 1 D-11: n = 2 D-12: n = 3 D-13: n = 4 D-14: n = 6 D-15: n = 10

[0121]

[Outside 52] D-16: n = 8 D-17: n = 10

[0122]

[Outside 53]

[0123]

[Outside 54]

[0124]

[Outside 55]

[0125]

[Outside 56]

[0126]

[Outside 57]

[0127]

[Outside 58]

In the chiral smectic liquid crystal composition used in the present invention, other compounds such as dyes,
It is possible to add additives such as pigments, antioxidants and UV absorbers.

In the liquid crystal element of the present invention, the state of the smectic liquid crystal layer in the element is controlled by appropriately setting the element structure, the liquid crystal material, and other external processing conditions.

The liquid crystal device of the present invention constitutes a liquid crystal device having various functions. The most suitable example is to use the device in the display panel section, and the scanning line address information shown in FIGS. The liquid crystal display device is realized by taking the communication synchronizing means by the data format including the image information and the SYN signal. The symbols in the figure are as follows.

[0131] 101 liquid crystal display device 102 graphic controller 103 display panel 104 scanning line drive circuit 105 information line drive circuit 106 decoder 107 scanning line signal generation circuit 108 shift register 109 line memory 110 Information signal generation circuit 111 Drive control circuit 112 GCPU 113 Host CPU 114 VRAM

Generation of image information is performed by the graphic controller 102 of the main unit, and the signal transmission means (image information communication timing chart) shown in FIGS. 2 and 3 is used.
Is transferred to the display panel 103. The graphic controller 102 is a CPU (central processing unit, GC
Abbreviated as PU112. ) And VRAM (memory for storing image information) 114 as cores for managing image information and communication between the host CPU 113 and the liquid crystal display device 101. In addition,
A light source is arranged on the back surface of the display panel.

In the display device of the present invention, since the liquid crystal element as the display medium has the good switching characteristics as described above, it is possible to obtain excellent driving characteristics and obtain a high-definition, high-speed, large-area display image. it can.

The driving method of the liquid crystal element of the present invention is, for example, Japanese Patent Application Laid-Open No. 59-193426 and Japanese Patent Application Laid-Open No. 59-19.
The driving methods disclosed in Japanese Patent No. 3427, Japanese Patent Application Laid-Open No. 60-156046, Japanese Patent Application Laid-Open No. 60-156047 and the like can be applied.

FIG. 6 is an example of a waveform diagram of the driving method. In addition, FIG. 5 is a plan view of an example of a ferroelectric liquid crystal panel in which matrix electrodes are arranged. In the liquid crystal panel 51 of FIG. 5, the scanning lines of the scanning electrode group 52 and the data lines of the information electrode group 53 are wired so as to intersect with each other, and the ferroelectric property is provided between the scanning line and the data line at the intersection. Liquid crystal is arranged.

In FIG. 6A, S _S is a selected scan waveform applied to the selected scan line, S _N is an unselected non-selected scan waveform, and I _S is selection information applied to the selected data line. it represents a non-selection information signal (white) for applying waveform (black) to the data lines I _N is not selected. In the figure the _{(I S -S S) (I} N -S S) is the voltage waveforms applied to pixels on a selected scanning line, the voltage (I _S -S _S) is applied pixel black take the display state, the voltage (I _N -S
_The pixel to which _S ) is applied becomes a white display state.

FIG. 6B shows the drive waveform shown in FIG. 6A, which is a time-series waveform when the display shown in FIG. 4 is performed.

In the driving example shown in FIG. 6, the minimum application time Δt of the single polarity voltage applied to the pixel on the selected scanning line corresponds to the time of the writing phase t2, and the one line clear t1.
The phase time is set to 2Δt.

The values of the parameters V _S , V _r , and Δt of the drive waveform shown in FIG. 6 are determined by the switching characteristics of the liquid crystal material used.

FIG. 7 shows the transmittance T when the drive voltage (V _S + V _I ) is changed while keeping the bias ratio, which will be described later, constant.
Of VT characteristics, that is, VT characteristics. Here, Δt = 50 μsec, bias ratio V _I / (V _I + V
_S ) = 1/3 fixed. The positive side of Fig. 7 is shown in FIG. 6 (I _N -S _S), the negative side indicates people respectively the final transmittance of the state when the waveform shown is applied in (I _S -S _S).
On the positive side, the previous state is black (the state where the transmittance is small), and on the negative side, the previous state is the white (the state where the transmittance is large).

Here, V1 and V3 are referred to as an actual drive threshold voltage and a crosstalk voltage, respectively. Also, V2 <V1 <
When V3, ΔV = V3−V1 is called a voltage margin, which is a voltage width that allows matrix driving. It can be said that V3 is generally present in driving the ferroelectric liquid crystal display device. Specifically a voltage value causing switching by V _B in the waveform of FIG. _{6 (A) (I N -S} S). Of course, it is possible to increase the value of V3 by increasing the bias ratio. However, increasing the bias ratio means increasing the amplitude of the information signal, which causes an increase in flicker in image quality and contrast. Is caused, which is not preferable.

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

Similarly, the above voltage is kept constant,
It is also possible to drive by changing the voltage application time Δt. The above voltage may be used as the voltage application time as it is, and at this time, the voltage application time threshold value is Δt1.
And the voltage application time crosstalk value is Δt2.
t2-Δt1) = ΔT is referred to as a voltage application time margin.

At a certain constant temperature, it is possible to write two states, black and white, to the selected pixel depending on the two directions of the information signal, and the non-selected pixel retains the black or white state. The voltage margin or the voltage application time margin that can be achieved differs depending on the liquid crystal material and the device configuration, and is unique. Further, since the driving margins vary depending on the change of the environmental temperature, it is necessary to set the optimum driving condition for the liquid crystal material, the element structure and the environmental temperature in the case of an actual display device.

In the present invention, in order to quantitatively evaluate the drive margin, a certain drive waveform that is fixed in a similar manner is used, and the voltage application time threshold Δt1 and the voltage application time crosstalk value Δt2 are used. Is measured, and a parameter “M2” (M2 margin) that represents the width from the center value of these values by a ratio is used.

M2 = (Δt2−Δt1) / (Δt2 + Δt1) <Example> The present invention will be described in more detail in the following examples.

(Experiment 1) The following liquid crystalline compounds (a) to
Liquid crystal compositions FLC-1 to FLC-3 were prepared using (f).

[0148]

[Outside 59]

[0149]

[Outside 60] Spontaneous polarization (Ps) (30 ° C.) = 31.1 nC / cm ² Layer spacing d (Tac, 41 ° C.) = 31.756Å Layer spacing d (30 ° C) = 31.636Å Layer tilt angle (calculated value) δcal (30 ℃) = cos ^-1 (d (30 ℃) / d (T
ac, 41 ° C)) = 5.0 °

[0150]

[Outside 61] Spontaneous polarization (Ps) (30 ° C.) = 20.7 nC / cm ² Layer interval d (Tca, 44 ° C.) = 31.596Å Layer interval d (30 ° C) = 31.360Å Layer tilt angle (calculated value) δcal (30 ℃) = cos ^-1 (d (30 ℃) / d (T
ac, 44 ° C)) = 7.0 °

[0151]

[Outside 62] Spontaneous polarization (Ps) (30 ° C.) = 22.1 nC / cm ² Layer spacing d (Tca, 52 ° C.) = 31.62Å Layer spacing d (30 ° C) = 31.04Å Layer tilt angle (calculated value) δcal (30 ℃) = cos ^-1 (d (30 ℃) / d (T
ac, 52 ° C.)) = 11.0 ° * Layer spacing was measured by the method described below. Layer spacing (Tac): Layer spacing at the phase transition temperature of SmA → SmC ^*

[Creation of Cell] Three types of empty cells used in the examples were prepared as follows.

Cell A: I having a thickness of about 70 nm as a transparent electrode
A polyimide (precursor) having the following repeating unit was applied to a 1.1 mm-thick glass substrate (two used) having a TO film formed thereon by a spin coating method. Then 80
After pre-drying at 5 ° C. for 5 minutes, heating and baking were performed at 200 ° C. for 1 hour to form an orientation control film. The film thickness at this time was 5 nm. The polyimide on both substrates was rubbed with a nylon cloth as a uniaxial orientation treatment.

[0154]

[Outside 63]

Then, as a spacer on one of the substrates,
Silica beads having an average particle diameter of 2.0 μm were dispersed and the other substrate was overlaid to prepare a cell.

Cell B-1: A polyimide (precursor) having the following repeating unit was spin-coated on one of two 1.1 mm-thick glass substrates on which an ITO film having a thickness of about 70 nm was formed as a transparent electrode. Applied. afterwards,
After pre-drying at 80 ° C. for 5 minutes, it was heated and baked at 200 ° C. for 1 hour to form an orientation control film. The film thickness at this time was 5 nm. This substrate was rubbed with a nylon cloth as a uniaxial orientation process.

[0157]

[Outside 64]

Regarding the second substrate, SnO _x oxide ultrafine particles (particle size 1
An ethanol solution having a solid content concentration of 10 wt% in which 00Å) was dispersed was applied by a spin coating method to a film thickness of 2000Å. Then, after pre-drying at 80 ° C. for 5 minutes, 200
It heat-dried at 1 degreeC.

Subsequently, silica beads having an average particle diameter of 2.0 μm were dispersed as spacers on the first glass substrate which had been subjected to the orientation treatment, and the other second substrate was superposed to prepare a cell.

Cell B-2 (cell for X-ray measurement):
Instead of using two 1.1 mm thick glass substrates, 8
Cell B- except that two glass substrates with a thickness of 0 μm were used.
It was prepared by the same method as in 1.

Cell C-1: A polyimide (precursor) having the following repeating unit was spin-coated on one of two 1.1 mm-thick glass substrates on which an ITO film having a thickness of about 70 nm was formed as a transparent electrode. Applied. afterwards,
After pre-drying at 80 ° C. for 5 minutes, it was heated and baked at 200 ° C. for 1 hour to form an orientation control film. The film thickness at this time was 6 nm. This substrate was rubbed with a nylon cloth as a uniaxial orientation process.

[0162]

[Outside 65]

As for the second substrate, SnO _x oxide super-particles (particle size: 10
An ethanol solution having a solid content concentration of 10 wt% in which 0Å) was dispersed was applied by a spin coating method to a film thickness of 2000Å.
Then, after pre-drying for 5 minutes at 80 ℃, 200 ℃ 1
It was heat dried for an hour.

Subsequently, silica beads having an average particle size of 2.0 μm were dispersed as spacers on the first glass substrate that had been subjected to the alignment treatment, and the other second substrate was overlaid to form a cell.

Cell C-2 (cell for X-ray measurement):
Instead of using two 1.1 mm thick glass substrates, 8
Cell C- except that two 0 μm thick glass substrates were used.
It was prepared by the same method as in 1.

A liquid crystal element was prepared by variously combining each cell prepared by the above-mentioned process with each liquid crystal composition. Further, a step (reorientation) of once heating to an isotropic liquid and cooling to room temperature was performed, and samples (liquid crystal elements) were prepared by changing the slow cooling rate variously in the step, and the orientation state was observed. Table 1 shows combinations of cells, compositions, and cooling conditions of each sample.

Regarding the alignment defect, the polarizing microscope was set to the crossed Nicols state of the pair of upper and lower polarizing plates, the liquid crystal element was set to the re-dark position in the electroless applied state, and then rotated by about ± 10 degrees to perform rubbing treatment. Alignment defects appearing as light leakage were observed along the direction and its vertical direction.

As a result of observing several tens of kinds of cells, liquid crystal elements (elements 1, 2-1, 2-2,
3-1, 3-2, 4 '), a region in which no alignment defect was observed could be recognized in the area of several microns to several hundreds of microns.

[0169]

[Table 11]

The region where no alignment defect is observed is P
One region, and a region where a minute alignment defect is recognized, is referred to as P2 region. Regarding the area ratio, after taking a micrograph (1 mm × 1 mm) of the region containing these defects, the weight of each of the two regions on each photo paper was measured and compared.

With respect to the obtained device, 1) analysis of the layer structure of liquid crystal (structure of smectic layer) in a minute region by X-ray diffraction, (device 2-2, 3-2, 4-)
2) 2) Contrast (C / R) 3) M2 margin (M2) was measured.

1) Analysis of Layered Structure of Minute Area by X-ray Diffraction Basically, the method carried out by Clark and Lagerwall (“Japan Display” '86, Se.
p. 30-Oct. 2, 1986.456-458, the layer spacing d and the inclination angle δ of the smectic layer were determined. As the measuring device, an X-ray diffractometer (manufactured by MAC Science) equipped with a rotating cathode X-ray generator as shown in FIG. 8 and equipped with an automatic temperature control device is used. In order to reduce the absorption of X-rays, the substrate has a Microsheet 804 (80 μm
Thickness) was used.

First, the layer interval d was measured by using the bulk liquid crystal 8 as a sample.
01 (liquid crystal composition to be injected into the cell) on a glass substrate for 5 m
A powder X-ray diffraction method (X-ray source 802, counter 80
The peak obtained in 3) was applied to the Bragg diffraction conditional expression to obtain the peak.

The measurement temperature was 3 ° C. after each liquid crystal composition was brought into an isotropic liquid state in order to increase the smoothness of the diffractive surface, and the temperature was lowered every 1 ° C. near the transition point, The measurement was performed up to a temperature at which no diffraction peak was obtained. The automatic temperature control device used in the experiment showed a control accuracy of about ± 0.3 ° C. at each temperature (using a temperature control plate 805 and a temperature monitor thermocouple 806).

The measurement was carried out with an output of 45 kV-100 mA, a copper Kα ray (1.54050 Å) as an analysis line, and a slit D
S; 0.05 mm, SS; 0.05 mm, RS; 0.0
5 mm and the scanning speed is 3 deg. / Min.

With respect to the angle δ, in the device using the cells B-2 and C-2 described above, the liquid crystal in the cell was gradually cooled from the Iso phase, and X-ray detection was performed at the diffraction angle 2θ at which the layer spacing d was obtained. The instruments were combined, θ-axis scanning was performed, and calculation was performed by the method described in the above-mentioned document. From the measurement result (temperature characteristic) of the layer spacing d described above, the value of the calculated tilt angle was obtained by the following formula.

Δ = cos ⁻¹ (dc / dAc) (dc layer spacing at the relevant temperature, dAcSmA → SmC ^* layer spacing at the phase transition temperature)

Diffraction profiles were obtained by appropriately narrowing the beam size of X-rays and increasing the counting time as necessary in order to measure the microscopic regions. The result of analysis of the layer structure is shown.

<Results of Element 2-2> In the P1 region, a single peak was obtained in the vicinity of 0 ° as shown in X-ray diffraction profiles 11 and 12 of FIG. 9, and Clark and Rawell's Japan Display 'were observed. 86.198
6, it was confirmed that the structure of the smectic liquid crystal layer was a complete bookshelf structure. In the P2 region, as shown in X-ray diffraction profiles 13 and 14 in FIG. 10, two peaks due to the chevron structure are obtained, and the inclination angle δ of the layer obtained from the profile is calculated from the temperature characteristics of the layer spacing. It almost agrees with the value. In addition, in the P2 region, many small defects such as zigzag defects are observed, though they are not clear, and the X-ray diffraction peak is often broad as a whole. Therefore, the bending direction of the layer structure is different in the P2 region. It was determined that the chevron layer structure was mixed.

<Results in Element 3-2> Two peaks were obtained in the P1 region as shown in the X-ray diffraction profile in FIG. 11. The tilt angle δ of the smectic liquid crystal layer obtained from this profile was obtained. Has an inclination angle δ that is significantly smaller than the value calculated from the temperature characteristics of the layer spacing. P
In the two regions, as shown in FIG. 12, two peaks due to the chevron structure are obtained in X-ray diffraction profiles 15 and 16, and the inclination angle δ of the layer obtained from the profile is calculated from the temperature characteristics of the layer spacing. It almost agreed with the value. Further, similar to the element 2-2, many small defects such as zigzag defects are observed in the P2 region, although they are not clear, and the X-ray diffraction peak is often broad as a whole. In the region, it is considered that the chevron layer structure having different bending directions of the layer structure is mixed.

<Results in Element 4-2> In this element, the area P1 in which no minute alignment defect is observed, which reaches the measurable area (several microns or more), is not observed. Three points were measured.

As shown in FIG. 13, two peaks due to the chevron structure are obtained in the X-ray diffraction profiles 17 and 18, and the tilt angle δ of the smectic liquid crystal layer obtained from the profile is calculated from the temperature characteristics of the layer spacing. It almost agreed with the value.

Further, similar to the P2 region of the elements 2-2 and 3-2, many small defects such as zigzag defects are observed, though they are not clear, and the X-ray diffraction peak becomes broad as a whole. Therefore, it is considered that the chevron layer structure having different bending directions of the layer structure is mixed in the P2 region.

From the analysis of the layer structure of the minute region by the above X-ray diffraction, the P1 region is a complete bookshelf layer structure,
Alternatively, the P2 region has a chevron layer structure having a remarkably small δ, and the P2 region has a chevron layer structure having a δ that substantially matches the value calculated by the temperature characteristic of the layer spacing, and further, the bending direction of the layer structure is different. It can be concluded that this is a region having a mixed state of chevron layer structure.

The structure of the smectic liquid crystal layer of the liquid crystal element related to the present invention will be described with reference to FIGS. 16 (A) to 16 (C).

FIG. 16A shows a liquid crystal element having a general chevron-shaped smectic liquid crystal layer. According to the element shown in the figure, the smectic liquid crystal layer 162 having a chevron shape bent between the pair of substrates 161a and 161b at approximately the midpoint between the substrates and having different bending directions.
There are two regions consisting of a and 162b. In such a device, these smectic liquid crystal layers 162a and 16a
2b may have a chevron shape bent in the same direction.

On the other hand, in FIGS. 16B and 16C,
1 shows a liquid crystal element according to the present invention.

In the elements shown in these figures, the pair of substrates 16
Between 1a and 161b, a region (corresponding to P1 region) made up of a smectic liquid crystal layer 163 that exhibits a bookshelf shape that is substantially perpendicular to the substrate, and a chevron shape that is bent near the midpoint between the substrates. And a region (corresponding to the P2 region) formed of the smectic liquid crystal layer 162a (162b) are mixed in the effective optical modulation region of the device.

In the element shown in FIGS. 16B and 16C,
In the smectic liquid crystal layer 163 in the P1 region, the tilt angle (measured value) of the liquid crystal layer with respect to the substrate normal is 3 degrees or less, or the tilt angle (measured value) of the liquid crystal layer is at least the temperature characteristic of the layer spacing of the liquid crystal layer. The value can be in the range of less than the value of the layer inclination angle obtained by the calculation based on, preferably less than 80% of the calculated value of the layer inclination angle. Also, P2
In the region, a chevron-shaped smectic liquid crystal layer bent in a single direction (layer 162a in FIG. 16B),
Or bent in a different direction (layer 16 of FIG. 16B).
2a and 162b).

2) Measurement of Contrast The method of measuring the contrast performed in the present invention will be described. First, a cell is installed between the polarizing plates arranged in crossed Nicols, and the drive waveform (Vop = 20V, 1/3.
3 bias, 1/1000 duty) is applied. Next, the pulse width is changed, and the element is rotated at an angle at which the darkest transmitted light intensity at the time of driving is obtained within the threshold pulse width of the bistable inversion, and the transmitted light intensity Ib at that time, the liquid crystal molecules The transmitted light intensity Iw when inverted was detected by a photodetector, and the ratio (C / R = Iw / Ib) was taken as the contrast evaluation value.

Further, in the example, the contrast measurement was performed on each of the P1 and P2 regions by narrowing the light from the light source. As shown in Table 2 below, a higher contrast value was obtained in the P1 region. The overall contrast in a state including both P1 and P2 regions is also affected by the P1 region, and particularly in the elements 1, 2 and 3 having a large area ratio of the P1 region, a larger value is shown than other elements. It was

3) Measurement of M2 margin Driving waveform similar to the above-mentioned measurement of contrast (see FIG. 1).
4: Vop20V, 1 / 3.3 bias, 1/1000
The duty was used to measure the M2 margin.
When the dark state and the bright state are written while changing the length Δt of the applied pulse waveform, and the range of the length Δt of the applied pulse waveform in which each of the bright and dark states can be written is as shown in FIG. 15, M2 = ( Δt2-Δt1) / (Δt2 + Δ
t1).

At that time, the M2 margin was measured for each of the P1 and P2 regions. In addition, a comprehensive M2 margin measurement was performed in a state including both P1 and P2 regions. As shown in Table 2, the value of M2 was larger in the P1 region than in the P2 region. The overall contrast in a state including both P1 and P2 regions was also influenced by the P1 region, and the element having a large area ratio of the P1 region showed a larger value than other elements.

The above results are summarized in Table 2 below.

[0195]

[Table 12]

The numerical values in parentheses in the above table indicate that the data of these characteristics include variations because the area of the P1 region is small.

From the results of 1) to 3), in the elements 1 to 3 (particularly 1, 2-1, 2-2, 3-1, 3-2, 4 '), regions having a bookshelf layer structure, Alternatively, there is a region where the layer inclination angle δ is significantly smaller than the value calculated from the temperature characteristic of the layer spacing (10% or more), and as a result, the device has a high contrast and a large M2 margin. You can

(Experiment 2) In Experiment 1, each cell (A, B-1, B-2, C-1,
C-2) and each liquid crystal composition (FLC-1, 2) were variously combined to prepare a liquid crystal element. Further, a step (reorientation) of once heating to an isotropic liquid and cooling to room temperature is performed, and in the step, (a) a step of cooling without applying an electric field, or (b) within a whole temperature range showing a smectic A phase In (3), a sample (element) was produced by applying any of the slow cooling conditions of the process of cooling while applying a rectangular wave of ± 30 V and 1 Hz, and the orientation state was observed.

Table 3 shows combinations of cells, compositions, cooling conditions, and electric field application conditions for each sample.

The elements 12-1, 12-3, 14-1,
And 14-3 are the elements 2-1 and 2- shown in Table 1, respectively.
The design is the same as 2, 4-1 and 4-2.

As a result of the observation, in the liquid crystal element shown in Table 3, a region in which no alignment defect was observed could be recognized in an area of several microns to several tens of microns.

[0202]

[Table 13]

The region where no alignment defects are observed is referred to as P1 region, and the region where minute alignment defects are recognized is referred to as P2 region.

For the obtained device, as in Experiment 1, 1) Analysis of the layer structure of liquid crystal in a minute region (structure of smectic layer) by X-ray diffraction, (Devices 12-4, 13-3, 1)
3-4, 14-4) 2) Contrast (C / R) 3) M2 margin (M2) was measured.

1) Analysis of Layered Structure of Minute Area by X-ray Diffraction The results of analysis of layered structure of minute area by X-ray diffraction are shown below. For the elements 12-3 and 14-3, the analysis results of the elements 2-2 and 4-2 in Experiment 1 described above apply, respectively.

<Results for Element 12-4> As for the element 12-4, the same analysis result as that for the element 12-3 using the same cell and composition, that is, the same as the above-mentioned analysis result for the element 2-2 was used. Results were obtained. Specifically, element 1
Regarding 2-4, although the area ratio of the element 12-3 is different from that of the P1 region and the P2 region, in the P1 region, the X-ray diffraction profile 11 and the X-ray diffraction profile 11 of FIG. As shown in Fig. 12, a single peak was obtained in the vicinity of 0 °, and Clark and Ragawell Japan
n Display '86 .1986, P456-45.
It was confirmed that the layer structure is a complete bookshelf structure in consideration of the description of 8 and the like. On the other hand, P of the element 12-4
In the 2 region, as shown in the X-ray diffraction profiles 13 and 14 of FIG. 10 relating to the element 12-3 (2-2) described above, two peaks due to the chevron structure are obtained,
The inclination angle δ of the layer obtained from the profile almost matched the value calculated from the temperature characteristics of the layer spacing. In addition, in the P2 region, many small defects such as zigzag defects are observed, though they are not clear, and the X-ray diffraction peaks are often broad as a whole. Therefore, the bending direction of the layer structure is different in the P2 region. It was determined that the chevron layer structure was mixed.

<Results of Devices 13-3 and 13-4> Although the devices 13-3 and 13-4 have different area ratios of the P1 region and the P2 region, both devices have the same X-ray profile in the P1 region. Although two peaks were obtained, the inclination angle δ of the layer obtained from this profile was significantly smaller than the value calculated from the temperature characteristics of the layer spacing.
have. On the other hand, in the P2 region, two peaks due to the chevron structure are obtained in both elements in the X-ray diffraction profile, and the inclination angle δ of the layer obtained from the profile is almost equal to the value calculated from the temperature characteristics of the layer spacing. Matched In addition, similar to the element 12-4, in the P2 region, many small defects such as zigzag defects are observed, although they are not clear.
Since the X-ray diffraction peak is often broad as a whole, it is considered that the chevron layer structure having different layer structure bending directions is mixed in the P2 region.

<Results with Element 14-4> Two peaks were obtained in the X-ray profile in the P1 region, almost similarly to the elements 13-3 and 13-4. The layer inclination angle δ is significantly smaller than the value calculated from the temperature characteristics of the layer spacing.
have. On the other hand, in the P2 region, two peaks due to the chevron structure were obtained in the X-ray diffraction profile, and the inclination angle δ of the layer obtained from the profile almost matched the value calculated from the temperature characteristics of the layer spacing. Also, P
In the region 2 there are many small defects such as zigzag defects, which are not clear, but many X-ray diffraction peaks are generally broad. Therefore, the bending direction of the layer structure is different in the region P2. It is considered that the chevron layer structure is mixed.

From the above analysis of the layer structure of the minute region by X-ray diffraction, in the above device, the P1 region is a region having a complete bookshelf layer structure or a chevron layer structure having a significantly small δ, It can be concluded that the P2 region is a region in which a chevron layer structure having δ that substantially matches the value calculated by the temperature characteristic of the layer spacing and a state in which chevron layer structures having different bending directions of the layer structure are mixed.

2) Contrast measurement The contrast measurement results (entire region P1 region, P2 region) of the above element sample are shown in Table 4 below. As shown in the same table, a higher contrast value was obtained in the P1 region. Was given. The overall contrast in the state of including both P1 and P2 regions is also affected by the P1 region, and in comparison of elements under similar processing conditions (slow cooling temperature and electric field application condition), the area ratio of the P1 region is particularly large. In the elements 11, 12, and 13 (compared with other elements, for example, the elements 11-1 and 12-
1, 13-1 showed a large value (compared with the element 14-1 etc.).

3) M2 Margin Measurement The M2 margin measurement results (entire region, P1 region, P2 region) of the above-mentioned element sample are shown in Table 4 below. As shown in the same table, the P1 region is the P2 region. A larger value of M2 was obtained. The total contrast in the state of including both P1 and P2 regions is also affected by the P1 region, and P
The element having a large area ratio in one region showed a larger value than the other elements.

[0212]

[Table 14]

The numerical values in parentheses in the above table indicate that the data of these characteristics include variations because the area of the P1 region is small.

From the results of 1) to 3), the elements 11-4 to 1
In 4-4, the region having a bookshelf layer structure or the inclination angle δ of the layer is set to a value calculated from the temperature characteristics of the layer spacing by optimally setting the element structure and the cooling process from the isotropic phase. There is a region having a remarkably small value (area ratio of about 5% to 25%). Then, by further cooling while applying an electric field within the temperature range showing the smectic A layer, the inclination angle δ of the region having the bookshelf layer structure or the layer is compared with the value calculated from the temperature characteristic of the layer spacing. The area ratio of the region with a remarkably small value increases dramatically (4 as the area ratio).
0% or more). As a result, an element having high contrast and a large M2 margin can be obtained.

[0215]

As described in detail above, according to the present invention,
A liquid crystal element that realizes a high contrast, has a large driving margin, and suppresses a decrease in contrast during driving, particularly a liquid crystal element that uses a chiral smectic liquid crystal,
Further, a liquid crystal device using the element is provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a structure of a liquid crystal element of the present invention.

FIG. 2 is a block diagram showing a configuration example of a liquid crystal display device of the present invention.

FIG. 3 is a diagram showing a timing chart of image information communication between a display device and a graphics controller applied in the present invention.

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

FIG. 5 is a plan view of a liquid crystal panel in which matrix electrodes are arranged.

FIG. 6 is a diagram showing an example of drive waveforms used to drive the liquid crystal element of the present invention.

FIG. 7 is a diagram (VT characteristic diagram) showing a change in transmittance when a drive voltage is changed.

FIG. 8 is a schematic diagram showing the structure of an X-ray diffraction apparatus used in an example of the present invention.

FIG. 9 is a chart showing an X-ray diffraction profile measured in an example of the present invention.

FIG. 10 is a chart showing an X-ray diffraction profile measured in an example of the present invention.

FIG. 11 is a chart showing an X-ray diffraction profile measured in an example of the present invention.

FIG. 12 is a chart showing an X-ray diffraction profile measured in an example of the present invention.

FIG. 13 is a chart showing an X-ray diffraction profile measured in an example of the present invention.

FIG. 14 is a diagram showing drive waveforms used for contrast measurement in an example of the present invention.

FIG. 15 is a diagram illustrating a drive margin (M2 margin) in the present invention.

16A to 16C are views for schematically explaining the structure of the smectic liquid crystal layer of the liquid crystal element related to the invention.

[Explanation of symbols]

1 liquid crystal 2 substrates 3 transparent electrodes 4 Alignment control layer 5 spacers 8 Polarized plate 9 light sources 101 liquid crystal display device 102 graphic controller 103 display panel 104 scanning line drive circuit 105 information line drive circuit 106 decoder 107 scanning line signal generation circuit 108 shift register 109 line memory 110 Information signal generation circuit 111 Drive control circuit 112 GCPU 113 Host CPU 114 VRAM

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kyoji Asao 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yukio Hanyu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Shuji Yamada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hirokatsu Miyata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-2-222930 (JP, A) JP-A-6-167711 (JP, A) JP-A-2-142753 (JP, A) JP-A-62-92918 (JP, A) Kai 62-173433 (JP, A) JP 3-92824 (JP, A) JP 4-296821 (JP, A) Special Table 7-506368 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) G02F 1/1337

Claims (5)

(57) [Claims] 1. A method of manufacturing a liquid crystal device, wherein a liquid crystal exhibiting a smectic phase is sandwiched between a pair of substrates provided with electrodes, wherein the liquid crystal is heated to an isotropic liquid without applying an electric field to room temperature. The liquid crystal portion is composed of a plurality of smectic liquid crystal layers by being cooled to a temperature, and in the liquid crystal portion, the smectic liquid crystal layer is inclined with respect to the substrate normal line calculated based on the temperature characteristics of the layer spacing of the liquid crystal layer. The region existing in a chevron shape with an inclination angle corresponding to the angle value and the smectic liquid crystal layer are smaller than the inclination angle value with respect to the substrate normal calculated based on the temperature characteristics of the layer spacing of the liquid crystal layer. A method for manufacturing a liquid crystal element, characterized in that regions having an inclination angle are mixed. 2. A method of manufacturing a liquid crystal device, wherein a liquid crystal exhibiting a smectic phase is sandwiched between a pair of substrates provided with electrodes, wherein the liquid crystal is heated to an isotropic liquid, and smectic A
By cooling to room temperature while applying an electric field in the phase, the liquid crystal portion is composed of a plurality of smectic liquid crystal layers, and in the liquid crystal portion, the smectic liquid crystal layer is calculated based on the temperature characteristic of the layer spacing of the liquid crystal layer. A region having a chevron shape with an inclination angle corresponding to the value of the inclination angle with respect to the substrate normal line, and the smectic liquid crystal layer has an inclination with respect to the substrate normal line calculated based on the temperature characteristics of the layer spacing of the liquid crystal layer. A method for manufacturing a liquid crystal element, characterized in that regions having an inclination angle smaller than the angle value are mixed. 3. The smectic liquid crystal layer substantially forms a region in which the smectic liquid crystal layer has an inclination angle smaller than a value of an inclination angle with respect to a substrate normal calculated based on a temperature characteristic of a layer spacing of the liquid crystal layer. 3. The method for producing a liquid crystal element according to claim 1, wherein the area is a bookshelf-shaped area in a vertical direction. 4. The liquid crystal according to claim 1, wherein in the region where the smectic liquid crystal layer exists in the chevron shape, a plurality of regions having different bending directions of the smectic liquid crystal layer are mixed. Device manufacturing method. 5. The optical element of the device is a region in which the smectic liquid crystal layer exists with a tilt angle smaller than a tilt angle value with respect to a substrate normal calculated based on the temperature characteristics of the layer spacing of the liquid crystal layer. 3. The method for producing a liquid crystal device according to claim 1, wherein the area ratio in the modulation region is 10% or more.