JPS60122919A - Liquid crystal element - Google Patents

Abstract

PURPOSE:To improve a monodomain forming property of a bistable liquid crystal, and display sufficiently its characteristic by providing a side wall for orienting a molecular axis of a liquid crystal in the parallel direction, and a side wall for being orthogonal to said side wall and orienting the liquid crystal in the vertical direction, on a cell structure body containing a liquid crystal consisting of a uniaxial liquid crystal phase. CONSTITUTION:An electrode group consisting of transparent electrodes 102, 102' being orthogonal to each other is formed on substrates 101, 101' of a cell structure body 100 formed by sticking a pair of substrates 101, 101' by an adhesive agent 106 through a spacer. An SmC* or SmH* liquid crystal layer 103 having a bistability is enclosed in the cell structure body 100. A parallel orientation control member 104, a side wall 104' for orienting a liquid crystal in the horizontal plane direction, a vertical orientation control member 105 in the direction orthogonal to the side wall 104', and a side wall 105' for orienting the liquid crystal in the vertical direction are provided, and when the liquid crystal layer 103 is dropped as to its temperature from a high temperature phase, a monodomain of an SmC* or SmH* phase is formed, and its bistable characteristic is displayed sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal element used in a liquid crystal display element, a liquid crystal light shutter, etc., and more specifically, the present invention relates to a liquid crystal element used in a liquid crystal display element, a liquid crystal light shutter, etc. It relates to liquid crystal elements.

Conventionally, liquid crystal display elements display images or information by configuring a scanning electrode group and a signal electrode group in a matrix, and filling a liquid crystal compound between the electrodes to form a large number of pixels.
well known.

The driving method for this display element is time-division driving, in which an address signal is selectively and periodically applied to a group of scanning electrodes, and a predetermined information signal is selectively applied in parallel to a group of signal electrodes in synchronization with the address signal. However, this display element and its driving method have major and fatal drawbacks as described below.

That is, it is difficult to increase the pixel density or enlarge the screen. Among conventional liquid crystals, most of them are practically used as display elements because they have relatively high response speed and low power consumption, for example, M, 8 CHD.
t and VV, “Applied P” by He1frich
hysics Letters”Vo, I B, N
4 (1971, 2, 15), P, 127-128 “Voltage-Dependent 0ptic
al Activity of a Twisted
Ne+natic Liquid Crystal”
TN (twisted nematic) shown in
In this type of liquid crystal, molecules of nematic liquid crystal with positive dielectric anisotropy are twisted in the thickness direction of the liquid crystal layer to form an fc structure (helical structure) in the absence of an electric field.
A structure is formed in which the molecules of this liquid crystal are arranged in parallel on the polar planes of both Immu. On the other hand, when an electric field is applied, positive rlj
Nematic liquid crystals with 't% anisotropy are aligned in the direction of the electric field, and as a result optical modulation can occur. When a display element is constructed with a matrix electrode structure using this type of liquid crystal, the area where both the scanning electrode and the signal electrode are selected (selected point) has liquid crystal molecules aligned perpendicular to the single pole plane. A voltage equal to or higher than the required threshold is applied to the region where neither the scanning electrode nor the signal electrode is selected (no voltage is applied to the non-selected point IC, and therefore the liquid crystal molecules maintain a stable alignment parallel to the electrode surface. By placing linear polarizers in a cross Nicol relationship above and below a liquid crystal cell, light does not pass through selected points, but light passes through non-selected points, making it possible to create a single-picture element. Become.

However, when a matrix electrode structure is configured, there are areas where scan electrodes are selected and signal electrodes are not selected, or where scan electrodes are not selected and signal electrodes are not selected. jj7. A finite electric field is also applied to the region where is selected (the so-called one half-selected point).The difference between the voltage applied to the selected point and the voltage applied to the half-selected point is sufficiently large, causing the liquid crystal molecules to be perpendicular to the electric field. If the '1 pressure threshold required for arraying is set to a voltage value in between, the display element will operate normally, but if the number of scanning lines (N) is increased, the entire screen will be During scanning (one frame), the time (duty ratio) during which an effective electric field is applied to one selected point decreases at a ratio of l/N.For this reason, when performing comb-over scanning The difference in effective pressure between the selected point and the non-selected point becomes smaller as the number of scanning lines increases, resulting in an unavoidable drop in image contrast and crosstalk. This phenomenon is caused by liquid crystals that do not have bistability (the stable state is when the liquid crystal molecules are aligned horizontally with respect to the polar plane, and they are aligned vertically only while an electric field is effectively applied). ) using the temporal accumulation effect (i.e.,
(repeated scanning) - an essentially unavoidable problem that sometimes arises. In order to improve this point, subsoil averaging method, dual frequency driving method, multiplexing method, etc. have already been proposed, but all of these methods are insufficient, and the large screen size of the display element is insufficient. At present, advances in technology and density have reached a plateau because the number of scanning lines cannot be increased sufficiently.

On the other hand, looking at the field of printers, laser beams are used to provide electrical image signals in the form of light to Kameko photoreceptors, both in terms of pixel density of 11t and speed, as a means of obtaining hard copies by inputting electrical signals. Printer (LBP)
is currently the best. However, LBP has drawbacks such as: 1. The device used as a printer is large; 2. It has a high-speed driving part such as a polygon scanner, which generates noise, and requires strict mechanical precision. In order to overcome these drawbacks, a liquid crystal shutter array has been proposed as an element that converts electrical signals into optical signals. However, when providing pixel signals using a liquid crystal shutter array, for example, in order to write pixel signals at a rate of 16 dots/mm within a length of 210 mm, it is necessary to have more than 3000 signal generating units. Therefore, in order to provide independent signals to each, lead wires for sending signals had to be wired to all of the signal generating sections, which was difficult to manufacture.

Therefore, an attempt has been made to time-divisionally provide one LINE's worth of pixel signals using a signal generating section divided into several lines. In this way, the polarization that gives the signal,
This is because a plurality of signal generating sections can all be connected to 111i, and the amount of actual wiring can be significantly reduced.

However.

In this case, if the number of lines (N) is increased by using a liquid crystal that does not have bistability, as is usually done, the time for the number ON becomes essentially ]/N, which can be obtained on the photoreceptor. There are drawbacks such as the reduction of Mitsu surnames and the problem of crosstalk.

To improve the drawbacks of conventional liquid crystal devices, C1ark and Lagerwall proposed the use of bistable liquid crystal devices (Japanese Patent Laid-Open No. 107216/1983, U.S. Pat. No. 4,367,924).
number specification etc.). Bistable liquid crystals generally include chiral smectic C phase (SmC') or H phase (
8 mH') is used. This liquid crystal has a bistable state consisting of a first optically stable state and a second optically stable state with respect to an electric field, and is therefore different from the optical modulation element used in the above-mentioned TN type liquid crystal.

For example, the liquid crystal is aligned in a first optically stable state with respect to one Ht electric field vector, and the liquid crystal is aligned in a second optically stable state with respect to the other electric field vector. Furthermore, this type of liquid crystal has the property of very quickly taking one of the above two stable states in response to an applied electric field, and maintaining that state when no electric field is applied. By utilizing such properties, many of the problems of the conventional TN type device described above can be significantly improved. This point will be explained in more detail below in connection with the present invention. However, in order for an optical modulation element using this bistable liquid crystal to exhibit predetermined driving characteristics, the liquid crystal placed between a pair of parallel substrates must be It is necessary that the molecules be in such a state that conversion between stable states can occur effectively. For example, for a ferroelectric liquid crystal having an SmC' or SmH phase, there is a region in which the liquid crystal molecular layer having an 8mC or Sm)i phase is perpendicular to the substrate surface, and therefore the liquid crystal molecular axes are aligned 17 approximately parallel to the substrate surface. (monodomain) needs to be formed. However, in conventional optical modulation elements using liquid crystals with bistability, the alignment state of the liquid crystals having such a monodomain structure was not always formed satisfactorily, and therefore sufficient characteristics could not be obtained. However, in order to provide such an orientation state, methods of applying a magnetic field, methods of applying a shear force, etc. have been proposed.

None of these necessarily gave satisfactory results. For example, the method of applying a magnetic field requires large-scale equipment and is incompatible with thin-layer cells with good operating characteristics. This method has the disadvantage that it is incompatible with the method of injecting liquid crystal.

By the way, in the device using the TN type liquid crystal as mentioned above,
For example, one way to form monodomains of liquid crystal molecules parallel to the substrate surface is to rub the substrate surface with something like a can (
A rubbing method, a method of diagonally depositing SiO, etc. are used.

For example, the liquid crystal in contact with the rubbed substrate surface is given a directionality, and the liquid crystal molecules preferentially align in that direction, which has the lowest energy (that is, is stable).
state. Such a rubbed surface has the effect of preferentially arranging liquid crystal molecules in one direction. For example, a structure with a plane that has an orientation effect of
W, Hel f r ich and M, 5chadt
This is shown in Canadian Patent No. 1010136, etc.

In addition to the method of forming an alignment effect by this rubbing method, there are also methods for forming an alignment effect such as SiO or 8i0. A structure having a plane formed by oblique vapor deposition is used, and this plane having uniaxial anisotropy of SiO or 5io2 has the effect of preferentially aligning liquid crystal molecules in one direction.

In this way, alignment control methods such as rubbing and oblique evaporation are one of the preferred methods for producing liquid crystal elements, but these methods cannot be used to control alignment for liquid crystals that have bistability. When this is applied, a plane having a wall effect that preferentially orients the liquid crystal in only one direction is formed, which has the drawback of inhibiting bistability to electric fields, high-speed response, and monodomain formation. The main purpose of this is in view of the above-mentioned circumstances.

Conventional problems have been solved in optical modulators using bistable liquid crystals, which have potential suitability for high-speed conversion, high-density pixel and large-area display elements, or optical shutters with high shutter speeds. Orientation of liquid crystal that can fully exhibit its characteristics by improving the monodomain formation property or initial orientation 111
1. To provide the Ml method.

As a result of further research for the above-mentioned purpose, the present inventors discovered a method of rubbing the plane of the substrate, and a method of rubbing 8i0 and sro on the plane of the substrate.
There is no problem with orientation control methods such as oblique evaporation, and it is possible to change from a high-temperature phase (e.g. isotropic phase, nematic phase, cholesteric phase) to an axially anisotropic phase (e.g. smectic phase nematic phase). When a phase transition occurs in the descending process of the liquid crystal, the side wall surface has the effect of aligning the liquid crystal in a direction parallel or substantially parallel to the molecular axis of the liquid crystal, and the side wall surface has the effect of aligning the liquid crystal in a direction perpendicular or substantially perpendicular to the molecular axis of the liquid crystal. We discovered that monodomains can be formed by controlling the alignment direction.

The liquid crystal device of the present invention was made based on this knowledge, and more specifically, the liquid crystal device has a large cell structure that has a liquid crystal that forms uniaxial anisotropy (for example, smectic phase, nematic phase) between a pair of substrates. In a liquid crystal element having a body,
The cell structure extends perpendicularly or substantially perpendicularly to a first side wall surface that has the effect of preferentially arranging the molecular axes of the liquid crystal in a parallel or substantially parallel direction. The liquid crystal element is characterized by having a side wall surface having a straight line, and the second side wall surface having an effect of preferentially arranging the molecular axis direction of the liquid crystal in a vertical or substantially vertical direction.

Hereinafter, the present invention will be described in further detail with reference to the drawings as necessary.

Particularly suitable liquid crystal materials for use in the present invention are those having bistability and strong electrical properties, specifically chiral smectate C phase (
A liquid crystal having a phase SmC) or an H phase (SmH') can be used.

For details on compulsory liquid crystals, see for example Ll and J 0
UI(N肚DE PHYSIQUg LBTTER8”
(L-69) 1975, [Ferroelectri
c Liquid Crystal J; 'App
Lied Physics Letters ”36
(11) 1980 [8ub+n1cro 5econ
dBi-5tablehlectrooptic
Switching in Liquid Crystal
als J: 1 Solid State Physics "■ (141) 1981r Liquid Crystal", etc., and the ferroelectric liquid crystal disclosed in these can be used in the present invention.

Specific examples of ferroelectric liquid crystal compounds include desiloxybenzylidene-V-amino-2-methylphthyl cinnamate (DOBAMBC) and hexyloxybenzylidene-P'-amino-2-rio.

Propyl Cinname) (HOBACPC), 4-〇-
(2-Methyl)-phthyl resol cylidene-4-octylaniline (MBH, A8) is mentioned.

When constructing an element using these materials, the element is supported by a copper block with a heater embedded, etc., as necessary, in order to maintain the temperature state such that the liquid crystal compound becomes the SmC phase or the SmH phase. be able to.

FIG. 1 schematically depicts an example of a cell for explaining the operation of a ferroelectric liquid crystal. 11 and 11' are In
,0. ．． 8nO, or ITO (Indium-'
It is a substrate (glass plate) coated with a transparent electrode made of a thin film such as L'in Qxide), and 8mC phase or SmH phase liquid crystal is sealed in which the extended liquid crystal molecular layer 12 is oriented perpendicular to the glass surface. ing. Thick line 13
represents a liquid crystal molecule, and this liquid crystal molecule 13 has a dipole moment (on P) 14 in a direction perpendicular to the molecule. When a voltage higher than a certain threshold is applied between the electrodes on the substrate 11 and ll', the helical structure of the liquid crystal molecules 13 is unraveled, and the liquid crystal molecules 13 are turned so that all the dipole moments (PL) 14 are directed in the direction of the electric field. The orientation direction can be changed. The liquid crystal molecules 13 have an elongated shape,
It exhibits refractive index anisotropy in the long axis and short axis directions, and therefore, for example, if crossed Nicol polarizers are placed above and below the glass surface, a liquid crystal optical modulation element whose optical characteristics change depending on the polarity of voltage application can be obtained. , easily understood.

The liquid crystal cell preferably used in the optical modulation element of the present invention can have a sufficiently thin thickness (for example, 1Oμ or less). As the liquid crystal layer becomes thinner in this way, the helical structure of the liquid crystal molecules becomes 11 and becomes a non-helical structure even when no electric field is applied, as shown in Figure 2, and the dipole moment) P or P' becomes The state is either upward (24) or downward (24'). When an electric field E or E' of a different polarity above a certain threshold value is applied to such a cell by the pressure applying means 21 and 21' as shown in FIG. 2, the dipole moment becomes t 1; Corresponding to the electric field vector of E', the direction changes to upward 24 or F direction 24', and accordingly, the liquid crystal molecules enter the first stable state 2.
3 or the second stable state 23'.

As mentioned earlier, there are two advantages to using such ferroelectricity as an optical modulation element.

The first is that the response speed is extremely fast, and the second is that the alignment of liquid crystal molecules has bistability. To further explain the second point, for example, with reference to FIG. 2, when an electric field E is applied, the liquid crystal molecules are oriented in a first stable state 23, and this state remains stable even when the electric field is turned off. Furthermore, when an opposite electric field E' is applied, the liquid crystal molecules enter a second stable state 23.
', and changes the orientation of the molecule, but it remains in this state even when the electric field is turned off. Further, as long as the applied electric field E does not exceed a certain threshold value, each orientation state is maintained. In order to effectively realize such fast response speed and bistability, it is preferable that the cell be as thin as possible.

The biggest problem in forming devices using liquid crystals with such ferroelectricity is, as mentioned earlier, that SmC
It is difficult to form a highly monodomain cell in which a layer having a phase or 8mH' phase is aligned perpendicularly to the substrate surface and liquid crystal molecules are aligned approximately parallel to the substrate surface, and this point It is the main objective of the present invention to solve this problem.

FIGS. 3(A) to 3(C) show an embodiment of the liquid crystal element of the present invention. FIG. 3(A) is a plan view of the liquid crystal element of the present invention, and FIG. 3(B) is a sectional view taken along the line AA'.
Figure (C) is a cross-sectional view taken along line B-B'. The cell structure 100 shown in FIG. It has a cell structure in which the pair of substrates are bonded with an adhesive 106, and furthermore, on the substrate 101, there are a plurality of transparent electrodes 102, a pole group (for example, a matrix), an IJ Of the electrode structures, the scanning pressure applying electrode group) is formed in a predetermined pattern such as a strip pattern.

On the substrate 101', an electrode group (for example, a signal voltage application electrode group in a matrix electrode structure) is formed, which is made up of a plurality of transparent electrodes 102' intersecting with the transparent electrode 102 described above.

Such a substrate 101 and 10IK: are, for example, silicon oxide, silicon dioxide, or aluminum oxide.

Zirconia, magnesium fluoride, cerium oxide, cerium fluoride, silicon i! silicon carbide, boron nitride, polyvinyl alcohol, polyimide, polyamideimide, polyesterimide, polyparaxylerin, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyamide, polystyrene,
An insulating film (not shown) made of cellulose resin, melamine resin, urea resin, acrylic resin, or the like can be provided. This insulating film also has the advantage of being able to prevent the generation of current caused by trace amounts of impurities contained in the liquid crystal layer 103, and therefore does not deteriorate the liquid crystal compound even if the operation is repeated. .

The liquid crystal layer 103 in the cell structure 100 shown in FIG.
It can be SmC or SmH. This 8 m C
The liquid crystal layer 103 exhibiting "or SmH" is formed by another phase on the higher temperature side than the smectic phase, for example, SmC or SmH in the precipitation process.
It is formed by a phase transition.

The unique point of the present invention is that when the phase transition is made from a high temperature phase to 8tnA, the molecular axes of the liquid crystal exhibiting amA are aligned in a direction parallel or approximately parallel to the side wall surface 104. The side wall surface 104' and the side wall surface 10 having the effect of
The point is that a monodomain SmA is formed under the control of the side wall surface 105 which has the effect of orienting the SmA in a direction perpendicular or substantially perpendicular to the SmA. The side wall surface 105 is disposed within the cell structure and extends perpendicularly or substantially perpendicularly to the side wall surface 104'.

The side wall surface 104 is a cut surface of the parallel alignment control member 104 that has the VJ friction effect when a film such as a polyester film or a polyimide film is cut into strips with a metal blade or a diamond blade, and a parallel alignment control member for glass fibers. The white side wall surface when used as the member 104 can be used.

In addition, polyimide, polyester, and S
Parallel orientation control member 1 such as iO or I/′1SIO7
When 04 is rubbed, a side wall surface 104' is formed, which has the effect of arranging the molecular axes of the liquid crystals in contact with each other at the interface in parallel or substantially parallel directions. Such a rubbed side wall surface 104 can be obtained by the following method. That is, ITO(Indium-Tin
-0xide), a highly hard coating, such as Si
After forming a C:H film and coating a polyimide precursor solution on the SiC:H film, an etching mask is formed through an exposure and development process, and then the polyimide precursor coating is etched. Then, a strip-shaped polyimide film that will become the parallel alignment control member 104 is formed at a predetermined position by heating, and then the etching mask is removed.

Thereafter, the substrate is rubbed in the same direction as the strip direction. The substrate surface has higher hardness and does not have the orientation control effect by rubbing, and the side wall surface 104 of the strip-shaped polyimide coating
′ has a parallel alignment control effect by rubbing.O In addition, a polymer forming highly oriented fibers and a child liquid crystal are used as the parallel alignment control member 104, and the fill li surface 104′ is in contact with the liquid crystal at the interface. The molecular axes of the molecules can be arranged in parallel or substantially parallel directions.

The polymer liquid crystal used to form such highly oriented fibers is, for example, a liquid crystal spun from a sulfuric acid solution of poly(p-phenylene tele-7 talamide) or a dimethylacetamide solution of poly(p-benzamide). Fiber is a typical fiber. Others include poly (
amide-hydrazide) and polyhydrazide sulfuric acid and 7
liquid crystal solution using sulfuric acid or a mixed solvent thereof, liquid crystal solution using polyphosphoric acid or methylsulfonic acid of poly(p-phenylenebenzobisoxazole) and poly(p-phenylenebenzobisthiazole), para-hydroxybenzoic acid , 1,2-bis(para-carboxy7eth/oxy)ethane, liquid crystalline melt of polyester formed from terephthalic acid and substituted or unsubstituted hydroquinone, para-hydroxybenzoic acid, 1,2-bis(para- Spinning from a liquid crystalline melt of a polyester produced from carboxyphenoxy)ethane, terephthalic acid, and bisphenol A or bisphenol A diacetate, a liquid crystalline melt of a polyester represented by the following general formula (1) or (2), etc. Examples include fibers obtained by

General formula (1) General formula (2) (in the formula, n = an integer of 2 to 11) By using such fibers in the parallel alignment control member 104, the liquid crystal in contact with the highly oriented side wall surface 104' of the fibers is the side wall surface 10
It can be oriented in a direction parallel or substantially parallel to 4'.

The side wall surface 105', which has the effect of arranging the molecular axes of the liquid crystal □ that are in contact with each other at the interface in a vertical or substantially vertical direction, can be obtained by, for example, forming a film of a fluororesin in a band shape.

The fluororesin preferably used in this case is one that is soluble in organic solvents. Specific fluororesins include, for example, copolymers using fluoroolefin, cyclohexyl vinyl ether, alkyl vinyl ether, and hydroxyalkyl vinyl ether as monomers (for example, those using chlorotrifluoroethylene, tetra7/I/oethylene as the fluoroolefin) , carbon number 2~ as alkyl vinyl ether
Fluoroolefins containing fluoroolefins and carboxylic acid ester groups as monomers (for example, hydroxybutyl vinyl ethers are suitable). A copolymer using chlorotrifluoroethylene or tetrafluoroethylene as a fluoroolefin (as a fluoroolefin having a carboxylic acid ester group) (:pt=CFO(CFt)a C0OCHs,
l 26 -COOCH3, etc.) can be used. Among them, fluoroolefins, cyclohexyl vinyl ethers, which can form a cured film in the presence of a crosslinking agent (for example, compounds having two or more active groups such as butylated melamine, methylated melamine, incyanate, and glyoxal are suitable) A copolymer containing alkyl vinyl ether and hydroxyalkyl vinyl ether as monomer components is one of the preferred fluororesins.

Further, other monomers such as glycidyl vinyl ether, ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride, ethyl vinyl ether, isobutyl vinyl ether, n-butyl vinyl ether, etc. can be added to the above-mentioned fluororesin.

The fluororesin used in the present invention can generally contain fluoroolefin in a proportion of 40 to 60 mol%, and can contain 2 to 40 to 60 mol% of other monomer components.

This film-forming fluorine-based copolymer resin includes disuccinic acid peroxide, diglutaric acid peroxide, monosuccinic acid peroxide, azobisisobutyramidine dibasic m, t-butylperoxyisobutyrate, t-butylperoxyacetate, etc. It can be obtained by copolymerizing the above-mentioned heptamer components in the presence of a polymerization initiator. Examples of the reaction solvent used in this polymerization include t-butanol, esters, and fluorine-based hydrocarbons. In addition, this fluororesin includes aromatic hydrocarbons such as xylene and toluene, alcohols such as n-butanol, esters such as butyl acetate, ketones such as methyl isobutyl ketone, glycol ethers such as ethyl cellosolve, etc. can be dissolved in organic solvents.

As a commercially available fluororesin that can form this type of film,
Lumi 70''' (manufactured by Asahi Glass) can be used.

Therefore, in forming the side wall surface 105', first, a coating solution obtained by dissolving a fluororesin as described above in an organic solvent is applied onto the substrate by a spinner coating method, and after preheating, A photoresist material is applied onto this coating film, and after a predetermined exposure is applied to the photoresist material, it is developed to form an etching mask.Then, the fluororesin coating film is etched with an organic solvent, and then the etching mask is removed. After that, the orientation control member 105 can be formed by heating the coating film formed in a band shape.

In addition, it is also possible to coat the side wall surface 105' by applying a fluororesin solution to a predetermined position using a screen printing method.
A vertical alignment control member 105 can be obtained.

In addition, orientation control members 201 (same material as 104) and 202 (same material as 104) and 202 (same material as 104) and 202 (same material as 104) are made of the same materials as the orientation control members 104 and 105 as described above, for example, as shown in FIGS. The alignment control members 203 (same material as 104) and 204 (same material as 105) can be used and further functioned as spacer members.
(same material) can be used. That is, the side wall surfaces of the orientation control members 201 and 203 in FIG. 4(4) have the same orientation control effect as the side wall surface 104' shown in FIG. Regarding the side wall surfaces 202 and 204, the side wall surface 105' shown in FIG.
It has the same orientation control effect as .

In such a cell structure 100, polarizers 107 and 108 in a crossed nicol state or a parallel nicol state are arranged on both sides of the substrate 101 and 1or, respectively, and the electrode 10
When a voltage is applied between 2 and 102', optical modulation will occur.

Next, regarding the method for manufacturing the liquid crystal element of the present invention, a method for controlling the orientation of the liquid crystal layer 103 will be specifically explained using FIG. 5, taking as an example the liquid crystal material DOBAMBC which exhibits ferroelectricity at a predetermined temperature.

Figure 5^ is a perspective view schematically showing the method for producing the liquid crystal element of the present invention, and Figure 5■ is the c-
c' sectional view, and FIG. 50 is a DD' sectional view. still,
Among the symbols in the drawings, the same ones as in FIG. 3 represent the same members.

*f, cell structure 10 in which DOBAMBC is encapsulated
0 is set in a heating case (not shown) such that the entire cell 100 is heated uniformly. Next, the temperature of the heating case is controlled so that the average temperature of the cell 100 is, for example, 70° to 90° C., and a liquid crystal layer 103 of SmA phase or 8mC* phase is formed.

The liquid crystal M 103 at this time is in a state before the lower alignment control method is applied, and no monodomain of SmA or SmC* is formed.

Here, a heating element 301 serving as a heating means is moved in the direction of an arrow mark 302. At this time, the heating element 301 causes Sm
The liquid crystal layer 103 in the region where the temperature has risen above the A→isotropic phase transition temperature (approximately 118° C.) enters the isobic phase state, but as the heating element 301 continues to move in the direction of the arrow 302,
This region immediately undergoes a cooling process from the isokyoshi phase state, and therefore the phase transition temperature (approximately 116°C) from isovolume to SmA is reached again.
When the temperature is lowered to below, monodomains of SmA oriented in one direction are formed.

At this time, since the parallel alignment control member 104 is provided in the present invention, heating by the heating element 301 causes
First, the temperature in the vicinity of the side wall surface 104' of the parallel alignment control member 104 reaches a temperature equal to or higher than the phase transition temperature to an equal force area (SmA -), and then the temperature decreases by moving the heating element 301 in the direction of the arrow shelf. SmAs arranged parallel or substantially parallel to the side wall surface 104' are formed at the interface of the side wall surface 104' at a temperature below the phase transition temperature of equal force to 8 mA. At this time, the orientation of SmA is further controlled by the side wall surface 105' of the vertical alignment control member 105, and SmA of liquid crystal molecules aligned in one direction is formed. Furthermore, the equal force area that continuously occurs due to the movement of the heating element 301 →
Forcing force and side wall surface 105'4- such that SmA generated by the phase transition to 8 mA is aligned parallel to the liquid crystal alignment generated near the side wall surface 104' of the parallel alignment control member 104.
As a result, a monodomain is formed in which the entire arrangement is parallel to the longitudinal direction of the side wall surface 10. Ru.

After that, in the process of cooling down from this SmA, S m 11
``Or, by phase transition to SmH, for example, if the cell thickness is reduced to about 2111 mm, monodomain SmC or 4iSmH with a non-helical structure can be obtained.

The heating element 301 used as a heating means has % SmA or 8
The cell structure 100 is heated to a temperature sufficient to cause mC* or S m H" to undergo a phase transition to an isovolume on the higher temperature side than 8 mA or 8 mC*, a nematic phase, or a cholesteric phase in the temperature raising process. , by moving the heating element 301 in the direction of the arrow 302, SmA or 8jm during the temperature cooling process.
It is moved at a speed sufficient to cause a phase transition to C*.

The heating element 301 used in such a method is, for example, a wire-shaped, roll-shaped, rod-shaped, or plate-shaped (band-shaped) nickel-chromium alloy or ITO.

A resistive heating element such as tin oxide or indium oxide can be used. If these heating elements are wire-shaped, roll-shaped, or rod-shaped, 1. Its diameter is 0.1
Approximately 111 to 5 degrees, preferably Q, 5. myx~2
Ill is suitable, and in the case of a plate-like or band-like shape, the width is about 0.1&II to 5wit, preferably 0.5u to 21I31+.

Also, its moving speed is 1 m/h -'-51 flll/h
is suitable.

FIG. 6 is a schematic diagram of a cell 41 having a matrix electrode structure in which a strongly hyperactive liquid crystal compound is sandwiched in the middle. 42 is a scanning electrode group, and 43 is a signal electrode group. Figure 7 (
a) and (b) are respectively selected scanning electrodes 42 (s
) and the other scanning electrodes (unselected scanning electrodes) 42 (n), and FIGS. 6(C) and (d) respectively show the electrical signals applied to the selected signal electrodes 43 (s ) and non-electrical signals applied to unselected signal electrodes 43 (n). In FIGS. 7(a) to (d), the horizontal axis represents time and the vertical axis represents voltage. For example, when displaying a moving image, the scanning electrode groups 42 are sequentially and periodically selected. Now, let us assume that the threshold voltage for providing the first stable state of the liquid crystal cell having bistability is v thl, and the threshold voltage for providing the second stable state is -Vth. As shown in FIG. 7(a), the electrical signal applied to s) is an alternating voltage such that it is V at phase (time) 1+ and -■ at phase (time) t. Also, other scans i! The pole 42(n) is in a grounded state as shown in FIG. 7(b), and has an electrical signal of 0. On the other hand, the selected signal electrode 43(s)
The electrical signal given to V is as shown in Figure 7(C).
, and the electric signal applied to the unselected signal electrode 43 (n) is <-V as shown in FIG. 7(d).

In the above, the voltage V is V<Vthl<2 V t-V>-Vth,>-2
It is set to a desired value that satisfies V. FIG. 8 shows the voltage waveform applied to each pixel when such an electric signal is applied. 8(a) to 8(d) correspond to pixels ASBSC and D in FIG. 6, respectively. That is, as is clear from FIG. 8, for the pixels on the selected scanning line, a voltage 2.sup.2 which exceeds the threshold value V.sub.th is applied at phase t. Further, to the pixel B existing on the same scanning line, a voltage of -2v exceeding the threshold value -vth is applied at phase t1. Therefore, depending on whether a signal electrode is selected on the selected scanning electrode line, if the signal electrode is selected, the liquid crystal molecules are aligned in the first stable state, and if not selected, the liquid crystal molecules are aligned in the second stable state. Adjust the orientation to a stable state. In any case, it has nothing to do with the previous history of each pixel.

On the other hand, as shown in pixels C and D, on unselected scanning lines, the voltage applied to all pixels C and D is +V or -■, neither of which exceeds the threshold voltage. Therefore, the liquid crystal molecules in each pixel C and D maintain the orientation corresponding to the signal state at the time of the previous scan without changing the orientation state (i.e., when the scanning electrode is selected). The signal for one line is written into the frame, and the signal state can be maintained until the next frame is selected.Therefore, even if the number of scanning electrodes increases, the actual The duty ratio does not change, and there is no reduction in contrast or crosstalk.In this case, the value of the voltage value and the value of the phase (t1+t,)=T depend on the liquid crystal material used and the thickness of the cell. It depends, but usually 0.1 μsec to 2 m at 3 volts to 7o volts
A range of sec is used. Therefore, in this case, the electrical signal applied to the selected scanning electrode is in the first stable state (assuming that it is in the "bright" state when converted into an optical signal).
A change can occur either from a second stable state (assuming a "dark" state when converted to an optical signal), or vice versa.

Hereinafter, the present invention will be explained according to examples.

[Example 1] A liquid crystal device was produced by the method shown in FIG.

This point will be explained in detail below.

Two notches with a depth of 2.5 μm were made parallel to the striped ITO film at both ends of a square glass substrate on which a striped ITO film with a pitch of 100 μm and a width of 62.5 μIn was provided as an electrode. It was set up like this.

Next, 100 parts by weight of fluorine-based resin "Lumiflon" (manufactured by Asahi Glass) was placed on the substrate except for this notch.
A coating solution consisting of 80 parts by weight of xylene, 80 parts by weight of n-butanol, 20 parts by weight of methylated melamine, and 0.5 parts by weight of "Catalyst 600" (manufactured by Asahi Glass ■) was applied using a spinner coater. , and dried to form a 2 μm fluororesin film.

Next, a positive resist solution (Bhi
Apply AZ1350″’ manufactured by Play with a spinner,
Pre-baked. An exposure mask was placed on this resist layer. However, as this exposure mask, a mask was used in which both ends of the glass substrate other than the notches provided at both ends were masked in a band shape.

After exposure, the resist film in the exposed areas was removed by developing with MF312°, a developer containing tetramethylammonium hydride tetraoxide, to form an etching mask. The fluororesin film was etched with a mixed solvent of 50).

Next, after the resin film was cured by heating under predetermined curing conditions, the etching mask was removed and vertical alignment control members were formed on both ends of the glass substrate.

Mylar film (registered product of DuPont, USA; polyethylene terephthalate film) cut with a metal blade was placed in the two notches of the substrate created in this way as a parallel alignment control member, and (5) an electrode plate was created. did.

Next, on the glass substrate, a width of 62 mm was formed with a pitch of 100 μm.
An @electrode plate was prepared by providing 5 μm striped electrodes. @After applying epoxy adhesive to the peripheral part of the electrode plate except for the area that will become the injection port, (g) Overlap the striped pattern electrodes of the electrode plate and the 0 electrode plate so that they are perpendicular to each other, and place them in the specified position. The cell was created by curing the adhesive under the following curing conditions.

After that, the Tokichi-phase DOBAMBC was created using the vacuum injection method.
was injected into the cell through the injection port, and the injection port was sealed.

After installing a pair of polarizers in a crossed nicol state on both sides of the cell injected with DOBAMBC, this was placed in a heating case controlled at a temperature of 90°0 and observed under a microscope. As a result, SmC* was formed. However, it was confirmed that it was not a monodomain.

The diameter of this liquid crystal cell is 0.21E when maintained at 90℃.
As shown in Figure 5, a Tuna Roof Simu alloy) heater was placed on the wire I so as to be parallel to one of the parallel alignment control members provided in the cell, and then a current was applied to the wire heater. caused a fever. At this time, the temperature of the liquid crystal cell heated by the wire heater is 120°C to 1.
After confirming that the temperature was 40° C., the wire heater was moved at a speed of 22 m/h in the direction of arrow 108 shown in FIG.

A pair of polarizers was placed on both sides of the liquid crystal thus created in a p-sequel state, and when it was observed under a microscope while maintained at a temperature of 90°C, it was confirmed that monodomain SmC* was formed. It was done.

Now, the alignment is completed through the steps described above, but even if the monodomains appear to be uniformly perfect, in reality, a voltage is applied between the electrodes 102 and 102' to form a liquid crystal optical modulator. When examining the switching characteristics of a semiconductor device, non-uniformity in optical contrast and response speed may occur depending on the region. This kind of phenomenon is caused by distribution.

It is thought that the cause is structural strain caused by the movement of the heater during internal operation.

To deal with this, after the alignment process is completed, the temperature of the carrier case is increased to cause a single carrier phase transition of the liquid crystal from the S m C'' phase to the 8 mA phase, and then the temperature of the case is increased again to the S!rIC* state. Gradual lowering has the effect of eliminating the above-mentioned distortion due to structural relaxation.

[Brief explanation of drawings]

Figure m1 and Figure 2 are perspective views showing the liquid crystal cell used in the present invention. FIG. 3 is a plan view showing the liquid crystal element of the present invention, and FIG.
is a BB' cross-sectional view thereof. FIGS. 4(5) and 4(c) are cross-sectional views showing another specific example of the liquid crystal element of the present invention. FIG. 5(5) is a perspective view schematically showing the method for manufacturing the liquid crystal element of the present invention, FIG. 'This is a cross-sectional view. FIG. 6 is a plan view schematically showing the electrodes and structure of the liquid crystal element used in the present invention. FIGS. 7(α) to (d) are explanatory diagrams showing signals for driving the liquid crystal element used in the present invention. FIG. 8 is an explanatory diagram showing the voltage waveforms applied to each pixel. Orientation control member 104': Side wall surface 105; Vertical orientation control member ios'; Side wall surface 106; Adhesive 107, 108; Polarizer 201; Parallel orientation control member 202 functioning as a sealing member; Vertical orientation control member functioning as a sealing member Member 203; Parallel orientation control member 204 functioning as a spacer member; Vertical orientation control member 301 functioning as a spacer member; Heat generating element 302; Moving direction of the heat generating element Patent source: Canon Co., Ltd. Suji 2 (21) -L;zu(c) (shi) (cl,) ('t,) (t)

Claims (1)

[Scope of Claims] (1) In a liquid crystal element having a cell structure that encapsulates a liquid crystal forming a uniaxial anisotropic phase between a pair of substrates, the cell structure prioritizes the molecular axis direction of the liquid crystal. a first side wall surface that has the effect of arranging them in a parallel or substantially parallel direction; and a second side wall surface that extends perpendicularly or substantially perpendicularly to the first side wall surface.
A liquid crystal element having a side wall surface of 0-+21 ftjI, characterized in that the second side wall surface has the effect of preferentially aligning the molecular axis direction of the liquid crystal in a vertical or substantially vertical direction. Smectic phase C or tl caused by phase transition from human phase
The liquid crystal element according to claim 1, which is in iH phase. (3) The liquid crystal element 0 according to claim 2, wherein the smectic C phase or H phase is a chiral smectic C phase or II phase. (4) The chiral smectic C phase or H phase is non-helical. A liquid crystal element according to claim 3, which has a structure. (5) The liquid crystal element according to claim 1, wherein the first side wall surface is formed of a resin or an inorganic substance. (6) The resin is polyvinyl alcohol, polyimide,
Polyamideimide, polyesterimide, polyparaxylylene, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, polyamide, polystyrene, cellulose resin, melamine resin,
6. The liquid crystal element according to claim 5, wherein the resin is at least one selected from the resin group consisting of Yuria resin, acrylic resin, and photoresist resin. (7) The liquid crystal element according to claim 1, wherein the first side wall surface is formed of a cylindrical member or a highly oriented fiber. (8) The liquid crystal element according to claim 7, wherein the cylindrical member is made of glass fiber. (9) The liquid crystal element 0 according to claim 1, wherein the second side wall surface is formed of a fluororesin. The liquid crystal element according to claim 1, wherein the liquid crystal element is arranged in a substantially parallel relationship. (11) The liquid crystal element according to claim 1, wherein the first side wall surface is a side wall surface of a sealing member. 07J The liquid crystal element according to claim 1, wherein the first side wall surface is a side wall surface of a spacer member.03 The cell structure has two or more second side wall surfaces in a parallel or substantially parallel relationship. Arranged claim 1
The liquid crystal element described in . (+41. The liquid crystal element according to claim 1, wherein the second side wall surface is a side wall surface of a sealing member. (4) Claim 1, wherein the second side wall surface is a side wall surface of a spacer member. The liquid crystal element described.