JPH11149077A - Method for manufacturing liquid crystal alignment film and method for manufacturing liquid crystal display device using the same - Google Patents

Abstract

[Problem] To provide a rubbing-free and extremely thin film having a thickness of a nanometer level and an alignment film for a liquid crystal in which the alignment direction of the liquid crystal is controlled by the polarization direction of the polarization exposure in a very short time, with high efficiency and uniformity. Form. Kind Code: A1 A chemically adsorbed liquid containing a non-aqueous organic solvent and a silane-based surfactant is applied to the surface of a substrate provided with electrodes in a dry atmosphere, and while the organic solvent is evaporated and concentrated, the surfactant molecules and the substrate are removed. The surface and the surface are subjected to a dehydrochlorination reaction, and the surfactant molecules 4 'are bonded and fixed to the surface of the substrate 1 at one end. The remaining unreacted surfactant is washed away. Examples of the silane-based surfactant include CH ₃ (CH ₂ )
₁₄ SiCl ₃ and a silane-based surfactant incorporating a photosensitive group: C ₆ H ₅ CH ＝ CHCOC ₆ H ₄ O (CH ₂ ) ₆ SiCl
₃ (1: 1 molar ratio) is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal alignment film, a method of manufacturing the same, a liquid crystal display device using the same, and a method of manufacturing the same. More specifically, the present invention relates to a liquid crystal alignment film used for a flat display panel using a liquid crystal for displaying a television (TV) image, a computer image, and the like, a method for manufacturing the same, a liquid crystal display device using the same, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a color liquid crystal display panel is formed by rubbing a polyvinyl alcohol or polyimide resin solution between two substrates having opposed electrodes formed in a matrix by spin coating with a spinner or the like. A device in which liquid crystal is sealed through a film has been generally used.

For example, a thin film transistor (TFT) array having pixel electrodes is formed on a first glass substrate in advance, and a plurality of red-blue-green color filters are formed on a second glass substrate. A common transparent electrode is formed on the surface, and a polyvinyl alcohol or polyimide solution is applied to each electrode surface using a spinner to form a film, then rubbed to form a liquid crystal alignment film, and optionally via a spacer. Liquid crystal (twisted nematic (TN), etc.)
Is injected to form a panel structure, polarizing plates are installed on the front and back of the panel, and T
A device that operates an FT to display a color image is known.

[0004]

However, the conventional method of forming an alignment film involves dissolving polyvinyl alcohol or a polyimide resin in an organic solvent, forming a coating film using a spin coater or the like, and then rubbing using a felt cloth or the like. It is difficult to make the film thickness uniform over the entire surface, and there is a limit to making the thickness thinner. There were major problems such as burnout and an increase in drive voltage.

[0005] The present invention is directed to an alignment film used in a liquid crystal display panel to solve the above-mentioned conventional problems.
The method is capable of forming a liquid crystal alignment film in which the alignment direction of a liquid crystal is controlled by the polarization direction of polarized light exposure in a short time, with high efficiency and uniformity, and a display element using the same. The aim is to provide a method.

[0006]

Means for Solving the Problems To achieve the above object, a first method of the present invention is to provide a chemically adsorbed liquid prepared using a non-aqueous organic solvent and a silane-based surfactant in a dry atmosphere. A step of coating the surface of the substrate with the electrodes, and a step of chemically reacting the surfactant molecules in the adsorbent with the substrate surface while evaporating and concentrating the organic solvent, thereby bonding and fixing the surfactant molecules to the substrate surface at one end. And a step of washing and removing unreacted surfactant remaining on the substrate surface using a non-aqueous organic solvent after a predetermined time after the evaporation of the organic solvent is completed. This is a method for producing a liquid crystal alignment film.

Next, a second method of the present invention comprises a step of applying a chemically adsorbed liquid prepared using a non-aqueous organic solvent and a silane-based surfactant in a dry atmosphere to the substrate surface on which the electrodes are formed. After evaporating the organic solvent, further reacting for a predetermined time, chemically reacting the surfactant molecules and the substrate surface to bond and fix the surfactant molecules at one end of the substrate surface, non-aqueous organic After washing and removing unreacted surfactant remaining on the substrate surface using a solvent, the method further comprises a step of setting the substrate in a desired direction, draining the washing solution, and pre-orienting the fixed molecules in the draining direction. This is a method for producing a monomolecular liquid crystal alignment film in which chemically adsorbed molecules are primarily aligned in a certain direction.

At this time, a relative humidity of 30
% Atmosphere or less is advantageous because a monomolecular liquid crystal alignment film can be produced without deactivating the silane-based surfactant near the substrate surface. In addition, when a silane-based surfactant containing a linear carbon chain or a siloxane bond chain and a chlorosilyl group, an alkoxysilane group, or an isocyanate silane group is used as the surfactant, a single molecule bonded to the substrate surface is extremely high in activity. When a film is formed, and a mixture of a plurality of silicon-based surfactants having different critical surface energies is used as a surfactant, the pretilt angle in liquid crystal alignment can be controlled, which is convenient.

For example, a carbon chain or a siloxane-bonded chain
A terminal or a part thereof is a carbon trifluoride group (—CF_Three), Mechi
Group (-CH_Three), Vinyl group (-CH = CH_Two), Allyl
Group (-CH = CH-), acetylene group (carbon-carbon 3
Heavy bond), phenyl group (-C ₆H_Five), Aryl group (-C
₆H_Four-), A halogen atom, an alkoxy group (-OR; R is
Represents an alkyl group. Preferred carbon numbers are in the range of 1-3.
Fence. ), Cyano group (-CN), amino group (-NH_Two),
Hydroxyl group (-OH), carbonyl group (= CO), carboxyl
Si group (-COO-) and carboxyl group (-COOH)
Substituted with at least one organic group selected from
It is convenient because the pretilt angle of the liquid crystal can be easily controlled.
You.

Further, if a step of exposing through a polarizing plate is further performed after draining the cleaning liquid, a monomolecular liquid crystal alignment film in which the liquid crystal is aligned along the polarization direction can be manufactured. In addition,
When exposure is performed through a polarizing plate, when a pattern-shaped mask is overlapped and exposed, it is convenient for forming a multi-domain structure by providing a plurality of portions having different alignment directions in a pattern in an alignment film in the same plane. Good.

Further, a silane-based surfactant containing a linear carbon chain or a siloxane bond chain and a chlorosilyl group or an isocyanate silane group is used as a surfactant, and a water-free non-aqueous organic solvent is used as a washing organic solvent. When used, it is convenient in removing excess surfactant.

Further, when a solvent containing an alkyl group, a carbon fluoride group, a carbon chloride group or a siloxane group is used as the non-aqueous organic solvent, it is more convenient to remove an excessive surfactant. Furthermore, before the step of fixing the surfactant molecules at one end, a step of forming a film containing a large number of SiO groups is performed, and a monomolecular film-like film is formed through this film, whereby a higher density can be obtained. This is convenient for producing a liquid crystal alignment film in a monomolecular film form.

Next, a first method for manufacturing a liquid crystal display device according to the present invention is directed to a method for manufacturing a first liquid crystal display device in which
Prepare a first substrate having a group of electrodes, and directly or after forming an arbitrary thin film, equipped with a non-aqueous organic solvent and a chemisorption solution prepared using a silane-based surfactant in a dry atmosphere equipped with electrodes A step of coating the surface of the substrate, and a step of chemically reacting the surfactant molecules in the adsorbent with the substrate surface while evaporating and concentrating the organic solvent to bond and fix the surfactant molecules to the substrate surface at one end. Washing and removing the unreacted surfactant remaining on the substrate surface using a non-aqueous organic solvent, and erecting the substrate in a desired direction, draining the washing solution, and removing the fixed molecules in the drain direction. A step of pre-orienting, a step of exposing through a polarizing plate, and a step of: exposing a first substrate and a second substrate having the first electrode group, or a second substrate having the second electrode or the electrode group. , While maintaining a predetermined gap with the electrode surface inside Performing a step of bonding and fixing to the combined location, the step of injecting a predetermined liquid crystal between the first and second substrates.

Next, a second method of manufacturing a liquid crystal display device according to the present invention is directed to a method of manufacturing a first liquid crystal display device in which a first liquid crystal display device is mounted in a matrix.
Preparing a first substrate having a group of electrodes, applying a chemical adsorption liquid prepared using a non-aqueous organic solvent and a silane-based surfactant in a dry atmosphere directly or after forming an arbitrary thin film; and Reacting a predetermined time after evaporating the organic solvent, chemically reacting the surfactant molecules with the substrate surface to bond and fix the surfactant molecules at one end to the substrate surface, and a non-aqueous organic solvent A step of washing and removing unreacted surfactant remaining on the substrate surface using, and a step of pre-orienting the fixed molecules in a draining direction by setting up the substrate in a desired direction and draining the washing solution. Exposing through a polarizing plate, and placing the first substrate and the second substrate having the first electrode group, or the second substrate having the second electrode or the electrode group, with the electrode surface inside. To maintain the specified gap A step of, I am advantageous in the manufacture of high-precision liquid crystal display device by performing the step of injecting a predetermined liquid crystal between the first and second substrates.

In the step of exposing through a polarizing plate, a patterning mask is superposed on the polarizing plate and exposed, and a plurality of portions having different patterning directions in the alignment film in the same plane are provided. This is convenient for manufacturing a liquid crystal display device having a domain type liquid crystal alignment film.

Further, when a silicone-based solvent is used as the non-aqueous organic solvent, it is convenient for producing a highly reliable liquid crystal display device with little evaporation residue. Furthermore, when a non-aqueous organic solvent having a boiling point of 100 to 250 ° C. is used, the solvent evaporation time is shortened, which is advantageous in shortening the film formation time. Further, in the step of applying the chemical adsorption liquid, it is convenient to use offset printing, screen printing, or a roll coating method because loss of the chemical adsorption liquid can be reduced.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a step of applying a chemically adsorbed liquid prepared using a non-aqueous organic solvent and a silane-based surfactant in a dry atmosphere to the surface of a substrate on which electrodes are formed, A step of causing a chemical reaction (elimination reaction such as dehydrochlorination reaction) between the surfactant molecules in the adsorbent and the substrate surface while evaporating to bond and fix the surfactant molecules at one end to the substrate surface; After the solvent evaporates for a predetermined time, a non-aqueous organic solvent is used to wash and remove the unreacted surfactant remaining on the substrate surface, thereby producing a monomolecular alignment film for liquid crystal. provide.

Furthermore, a step of applying a chemically adsorbed liquid prepared using a non-aqueous organic solvent and a silane-based surfactant in a dry atmosphere to the surface of the substrate on which the electrodes are formed, and evaporating and concentrating the organic solvent. A step of causing a chemical reaction (desorption reaction such as a dehydrochlorination reaction) between the surfactant molecules in the adsorbent and the substrate surface to bond and fix the surfactant molecules at one end to the substrate surface; After a predetermined time elapses, the unreacted surfactant remaining on the substrate surface is removed by washing using a non-aqueous organic solvent, and then the substrate is further set up in a desired direction to drain the washing solution. The present invention provides a liquid crystal alignment film in the form of a monomolecular film in which chemically adsorbed molecules are primarily aligned in a certain direction, wherein a step of pre-aligning the fixed molecules is performed.

Further, by applying the above method, a first substrate having a first electrode group mounted in a matrix in advance is prepared, and a thin film is formed directly or after forming an arbitrary thin film in a dry atmosphere. A step of applying a chemically adsorbed liquid prepared using an aqueous organic solvent and a silane-based surfactant, and a chemical reaction (dechlorination) between the surfactant molecules in the adsorbed liquid and the substrate surface while evaporating the organic solvent. Desorption reaction such as hydrogen reaction) to bond and fix the surfactant molecules to the substrate surface at one end, and after the organic solvent evaporates and elapses of a predetermined time, remains on the substrate surface using a non-aqueous organic solvent. Washing and removing the unreacted surfactant, setting up the substrate in a desired direction, draining the liquid, pre-aligning the fixed molecules in the draining direction, and exposing through a polarizing plate. And the first electrode Bonding and fixing the first substrate and the second substrate having the above or the second substrate having the second electrode or the electrode group while maintaining a predetermined gap with the electrode surface inside. A method for manufacturing a high-precision liquid crystal display device by using a step of injecting a predetermined liquid crystal between the first and second substrates is provided.

[0020]

The present invention will be described more specifically with reference to the following examples.
explain. (Example 1) Glass substrate 1 having a transparent electrode formed on the surface
(Including many hydroxyl groups on the surface)
Wash and degrease. On the other hand, the surface energy of the coating is
A linear hydrocarbon group incorporating one functional group
i-containing silane-based surfactants (hereinafter referred to as chemisorbed substances)
Or a chemisorbed compound), CH_Three(CH_Two)₁₄Si
Cl_ThreeAnd a silane-based surfactant incorporating a photosensitive group, C₆H
_FiveCH = CHCOC₆H _FourO (CH_Two)₆SiCl_Three(Molar ratio
And used at a concentration of 1% by weight.
Prepare a chemisorption solution by dissolving it in a non-aqueous solvent.
At this time, as the non-aqueous solvent (solvent not containing water),
Hexamethyl silicone (bp.100)
° C, and non-aqueous organic substances with a boiling point up to about 250 ° C
If the solvent is used, the evaporation time will be slightly longer, but there is no practical problem.
It was usable without a title. ) Was used. Like this
The prepared solution was used as an adsorption solution 2 in a dry atmosphere (relative
The humidity is 30% or less).
Was immersed (may be applied) for about 1 minute (FIG. 1). So
After that, pull up from the solution and in the same atmosphere
Is evaporated, and the concentration of the chemisorbed substance on the substrate surface reaches 100%.
After concentration, the reaction was continued for another 5 minutes. sand
That is, a coating consisting of only the chemisorbed substance was placed on the substrate surface.
Formed on the surface accelerated the reaction between the chemical adsorbent and the substrate surface.
After that, further dehydrated water in the same dry atmosphere
Washing with n-hexane 3 which is a non-aqueous solvent not containing
After cleaning, place the substrate in the desired direction
After withdrawing and draining, exposed to air containing water
(FIG. 2).

By the above treatment, the chemically adsorbed monomolecular film 4 formed by the reaction of the chlorosilane-based surfactant is bonded to the portion of the substrate surface containing the hydroxyl group via the covalent bond of siloxane. The bonded molecules were oriented in the direction opposite to the pulling direction 5, that is, along the draining direction, to form a film having a thickness of about 1.7 nm. At this time, the critical surface energy of the chemisorption film is about 28 mN /
m.

Therefore, using two substrates in this state, combining them so that the chemical adsorption films face each other and setting them so that the orientation directions are anti-parallel, assembling a liquid crystal cell with a 20 micron gap, nematic liquid crystal (ZLI47)
92; manufactured by Merck Co., Ltd.) to confirm the alignment state.
The injected liquid crystal molecules were oriented at a pretilt angle of about 4 ° with respect to the substrate toward the draining direction of the cleaning liquid. Incidentally, in the reaction between the surface of the substrate and the surfactant, first, bonds of the following formulas (Formulas 1 and 2) are generated at a ratio of approximately 1: 1. It was considered that a bond of the formula (Formulas 3 and 4) was formed by reacting with the water of formula (3). Note that the carbon chains of the molecules adsorbed at this time were oriented with a certain degree of inclination in the draining direction when analyzed by FTIR.

[0023]

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[0024]

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[0025]

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[0026]

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In the above-described series of chemical adsorption monomolecular film forming steps, after the solvent is evaporated, the chlorosilane-based surfactant is applied to the substrate surface in a state of being concentrated to 100%. Surfactant Si
Since a dehydrochlorination reaction occurs between the Cl group and the hydroxyl group on the substrate surface, the adsorption time, which is usually required for 1 to 2 hours, can be reduced to an extremely short time of 6 minutes. Next, the substrate in this state is
The polarizing plate 6 (HNP) is prepared so as to be further shifted by 3 degrees from the direction perpendicular to the respective pulling directions, that is, so that the polarizing direction 13 is directed to a direction crossing the pulling direction at 87 degrees.
'B: Polaroid Co., Ltd.) on the substrate, set
Irradiation at 400 mJ was performed using 365 nm (i-line) light 7 (3.6 mW / cm ² after passing through a polarizing film) from a 00 W ultra-high pressure mercury lamp (FIG. 4). FIG. 5 shows the chemically adsorbed monolayer without the polarizing plate 6 after the irradiation. In FIG. 5, reference numeral 8 denotes the direction of reorientation of the film molecules.

According to the above treatment, the molecule represented by the chemical formula 3 in the chemically adsorbed monomolecular film does not change according to the FTIR analysis, but the photosensitive group represented by the chemical formula 4 (C ₆ H ₅ CH ＝ CHCOC)
₆ H ₄ -) identifies that a light in the photosensitive 365 nm (i line) and a structure shown in photopolymerized by Formula 5. FIG.
In FIGS. 5 to 9, reference numeral 9 denotes a transparent electrode. FIG. 6 shows the structure of the membrane molecule. In FIG. 6, reference numeral 4 'denotes a chemisorption monomolecular film in which the reoriented photosensitive group is polymerized.

[0029]

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Further, the two substrates in this state are combined and set so that the chemical adsorption films 4 'face each other, and set so that the orientation direction is anti-parallel. A liquid crystal cell having a 20 micron gap is assembled, and the nematic liquid crystal (ZLI) is assembled.
When the alignment state was confirmed by injecting 4792 (manufactured by Merck & Co.), the injected liquid crystal molecules were oriented along the polarization direction at a pretilt angle of about 4 ° with respect to the substrate.

Incidentally, when the orientation direction of the linear carbon chain in the chemisorption monomolecular film 4 'was analyzed by FTIR, the critical surface energy and the tilt angle were not changed, but the orientation direction 8 was almost the same as the polarization direction 13. It changed in the parallel direction, and the alignment variation was also improved compared to the pre-liquid drainage alignment by pulling up.

At this time, in order to align the orientation direction of the adsorbed molecules in the irradiation section in one direction, it is necessary to completely adjust the orientation of the adsorbed molecules by 90%.
Instead of crossing at ゜, it is necessary to shift it slightly, preferably several degrees or more. If they intersect at exactly 90 °, individual molecules may be oriented in two directions. The polarization direction 13 is set so as to be parallel to the cleaning solution draining direction.
By combining these, a monomolecular film having further excellent alignment regulating force was obtained.

When it is desired to selectively change the orientation direction on the substrate surface, the liquid is pulled up beforehand and drained.
200-500 m by overlapping a pattern mask on a polarizing plate
When an ultraviolet ray having a wavelength of 365 nm is irradiated with the energy of J, only the irradiated portion changes the orientation direction, and the orientation direction changes in a pattern in the alignment film in the same plane, that is, the pulling-out liquid draining direction 5 and the polarization direction. A plurality of portions where the liquid crystal was aligned could be provided along each of 13.

When an atmosphere having a relative humidity of 35% or more was used as the drying atmosphere, a white film remained on the substrate surface even after washing, and could not be easily removed. In addition, although a silane-based surfactant containing a linear carbon chain or a siloxane-bonded chain and a chlorosilyl group was used as the surfactant, the reaction rate of the surfactant containing an alkoxysilane group or an isocyanate silane group was slightly slowed down. But was available.

Furthermore, as a surfactant, a plurality of types of silicon-based surfactants having different critical surface energies, for example, a terminal or a part of a carbon chain or a siloxane bonding chain is
3 fluorocarbon group (-CF _3), a methyl group (-CH _3), a vinyl group (-CH = CH _2), allyl (-CH = CH
-), an acetylene group (carbon - triple bond of carbon), a phenyl group (-C ₆ H _5), an aryl group (-C ₆ H ₄ -), a halogen atom, an alkoxy group (-OR; R is 1 carbon atoms To 3), a cyano group (-CN), an amino group (-
NH _2), a hydroxyl group (-OH), a carbonyl group (= C
When a surfactant substituted with at least one organic group selected from O), a carboxy group (—COO—) and a carboxyl group (—COOH) is used, the critical surface energy can be extremely easily adjusted within the range of 15 to 55 dyn / cm. Could be controlled.

When a solvent containing an alkyl group, a carbon fluoride group, a carbon chloride group or a siloxane group was used as the non-aqueous organic solvent, unreacted surfactant could be removed efficiently.

At this time, the composition of CH ₃ (CH ₂ ) ₁₄ SiCl ₃ and C ₆ H ₅ CH ＝ CHCOC ₆ H ₄ O (CH ₂ ) ₆ SiCl ₃ is changed from 1: 0 to 0: 1 (preferably 50: 1). １ ： 1: 5
0), the critical surface energy changes from 24 mN / m to 35 mN / m, each with a pretilt angle of 86 mN / m.
It could be controlled arbitrarily in the range of ゜ to 3 ゜. In addition, CH ₃
A surfactant containing fluorine as a chemisorption compound instead of (CH ₂ ) ₁₄ SiCl ₃ , for example, CF ₃ (CF ₂ )
_{As 7} (CH ₂ ) ₂ SiCl ₃ was added, the critical surface energy could be reduced to 14 mN / m. In the case of adding 20% by weight, the pretilt angle of the liquid crystal was almost 90 degrees, but when driven by applying a voltage, an extremely uniform alignment change was shown.

When a film is to be selectively formed,
A method of applying the adsorption liquid 2 to the substrate surface 1 in a desired pattern using offset printing, screen printing, or a roll coating method could be used.

As described above, in Example 1, the silane-based surfactant having a carbon chain length of-(CH ₂ ) _14- and-(CH ₂ ) ₆
-, A silane-based surfactant having a photosensitive group was used as a mixture, but the carbon chain length was different (for example,-(CH
₂ ) _n- ; n is an integer in the range of 1 to 25) Even when a surfactant is used in combination, the orientation direction can be controlled by the polarization direction, and the pretilt angle can be similarly controlled by the critical surface energy of the monomolecular film. Was. Similar alignment control was possible by incorporating a siloxane bond chain (-(SiO) _n- ; n is an integer in the range of 1 to 15) instead of the hydrocarbon chain.

Example 2 In Example 1, chlorosilyl groups were dried in a dry atmosphere (relative humidity: 30% or less) before the step of chemically adsorbing surfactant molecules containing carbon chains and siloxane bonding chains. Was prepared by dissolving a compound containing a plurality of compounds, and applied to the substrate surface and dried. Then
The adsorption solvent was evaporated, and the compound containing a plurality of chlorosilyl groups was concentrated. Finally, a film of the compound containing a plurality of chlorosilyl groups was formed. At this time, the chlorosilyl group of the compound containing a plurality of hydroxyl groups and chlorosilyl groups contained in the substrate surface undergoes a rapid dehydrochlorination reaction. Thereafter, when the substrate is further washed with a non-aqueous organic solvent containing almost no water and taken out into the air, the chlorosilyl groups remaining on the substrate surface react with the water in the air, and the surface contains SiOH bonds, that is, a large number of hydroxyl groups. A chemisorbed monolayer of inorganic siloxane was formed.

For example, Cl ₃ SiOSiCl ₃ is used as a silyl compound containing a plurality of chloro groups, dissolved in dehydrated toluene at a ratio of 1% by weight to prepare an adsorbent, and the substrate is immersed for about 1 minute in a dry atmosphere. After further lifting, drying in the same atmosphere for about 5 minutes to evaporate toluene, and reacting for 5 minutes, and then washing with well-dehydrated chloroform, the base material surface contains at least -OH groups. Therefore, a dehydrochlorination reaction occurred at the interface, and a monomolecular film-like coating 11 as shown in FIG. 7 was formed on the substrate surface via the -SiO- bond. Then take out further into the air,
When reacted with moisture in the air, a monomolecular film-like siloxane coating 12 containing a large number of hydroxyl groups (-OH) was formed on the substrate surface as shown in FIG. 8 via -SiO- bonds.

In the above-described series of chemical adsorption monomolecular film forming steps, after the solvent was evaporated, the silyl compound containing a plurality of chloro groups was applied to the substrate surface in a state of being concentrated to 100%. Since the dehydrochlorination reaction occurs between the SiCl group of the chlorosilane-based surfactant and the hydroxyl group on the substrate surface, the chemical adsorption time, which normally takes 1 to 2 hours, can be shortened to an extremely short time of 11 minutes.

Since the siloxane monomolecular film 12 formed at this time is completely bonded to the substrate through a chemical bond of -SiO-, it does not peel off. Moreover, the obtained monomolecular film has many SiOH bonds on the surface. Especially -O
About two to three times the number of H groups was generated at the beginning. The treated part in this state had extremely high hydrophilicity.

In this state, when a chemical adsorption step is performed using the same surfactant as in Example 1, a chemically adsorbed single molecule containing a carbon chain formed by the reaction of the same surfactant as in FIG. The film was formed to have a thickness of about 1.8 nm in a state where the film was chemically bonded by siloxane covalent bonds via the siloxane monomolecular film 12. At this time, the number of adsorption sites (OH groups in this case) on the surface of the base material before the surfactant is adsorbed is about 2 to 3 times as large as in Example 1, so that the adsorption is higher than in Example 1. The molecular density could be increased. Also, the processing unit became lipophilic.

Therefore, a liquid crystal cell having a 20 micron gap was assembled by using two substrates in this state and combining them so that the chemisorption films faced each other so that the alignment directions were antiparallel, and the nematic liquid crystal (ZLI4792;
(Merck) was injected and the alignment state was confirmed. It was confirmed that the injected liquid crystal molecules were aligned at a pretilt angle of about 5 ° with respect to the substrate along the chemically adsorbed molecules.

As a silyl compound containing a plurality of chloro groups, other than Cl ₃ SiOSiCl ₃ , Cl- (Si
_{Cl 2 O) n -SiCl 3 (} n is an integer. However 0,1～3
Was nice to handle. ) Was available.

(Example 3) In Example 1, instead of CH ₃ (CH ₂ ) ₁₄ SiCl ₃ , Cl was used instead of CH ₃ (CH ₂ ) ₁₄ SiCl _3.
Si (CH ₃ ) ₂ OSi (CH ₃ ) ₂ OSi (CH ₃ ) ₂ OS
When i (CH ₃ ) ₂ Cl is used by mixing between 1: 0 and 0: 1, the critical surface energy is 37 mN depending on the mixing ratio.
/ M to 23 mN / m. Further, when the liquid crystal was injected as in the case of assembling the cell, the pretilt angle could be controlled in the range of 5 to 87 degrees.

[0048] At a (Example 4) Example 1, in place of _{CH 3 (CH 2) 14 SiCl} 3 as a chemical adsorbate, CH _{3
^{CH 2 C * HCH 3 CH 2}} OCO (CH 2) 10 SiCl 3 ( however, C ^* is asymmetric carbon) of 1: 0 to 1: was produced in the same manner as the alignment film used in a mixture at between 20. In this case, the critical surface energy is between 31 mN / m and 41 mN / m depending on the mixing ratio.
It could be controlled in the range of mN / m. Furthermore, when the same liquid crystal was injected after the cell was assembled, the alignment direction of the liquid crystal was controlled by the rubbing direction, and the pretilt angle could be controlled in the range of 3 degrees to 0.1 degrees.

(Embodiment 5) Next, a manufacturing process for actually manufacturing a liquid crystal display device using the liquid crystal alignment film will be described with reference to FIG.

First, as shown in FIG. 9, on a first substrate 23 having a first electrode group 21 mounted in a matrix and a transistor group 22 for driving the electrodes, and a first electrode group 21 The prepared chemical adsorption liquid was applied to the second substrate 26 having the color filter group 24 and the second electrode 25 placed so as to face each other in accordance with the same procedure as in Example 1 to obtain a critical surface energy. Is 28m
A N / m primary-oriented chemically adsorbed monolayer was prepared.

Thereafter, polarization exposure was performed under the same conditions as in Example 1 to obtain a liquid crystal alignment film 27 having a critical surface energy of 27 mN / m in which linear hydrocarbon groups were realigned along the electrode pattern. . Next, the first and second substrates 2
The cells 3 and 26 were positioned so that the electrodes faced each other, and a spacer 28 and an adhesive 29 were used to form a cell in which the orientation direction was twisted 90 degrees with a gap of about 5 microns. Thereafter, the TN liquid crystal 30 was injected into the first and second substrates, and the polarizing plates 31 and 32 were combined in a crossed Nicols to complete a display device. The pretilt angle of the liquid crystal injected at this time is 4
Degree. Such a device could display an image in the direction of arrow A by driving each transistor using a video signal while illuminating the entire surface of the backlight 33.

(Embodiment 6) In the fifth embodiment, after performing primary alignment, a pattern mask for dividing each pixel into four in a checkered pattern is superposed on a polarizing plate and exposed four times. Thus, four portions having different alignment directions could be provided. When the substrate on which the alignment film was formed was used, the viewing angle of the liquid crystal display device could be greatly improved.

In the first embodiment, light of 365 nm which is i-line of an ultra-high pressure mercury lamp was used as light for exposure.
It is also possible to use light of 248 nm obtained by 05 nm, 254 nm or KrF excimer laser. Especially,
Since the light of 248 nm or 254 nm is easily absorbed by most substances, the energy alignment efficiency is high. Furthermore, when a step of exposing a desired mask to a polarizing plate and performing exposure under the same conditions was performed a plurality of times, a plurality of monomolecular liquid crystal alignment films having different alignment directions could be formed very easily in a pattern. That is, a liquid crystal display device in which one picture element is multi-domain aligned can be provided by this method.

[0054]

As explained above, according to the present invention, the thickness is extremely thin at the nanometer level, and the alignment direction of the liquid crystal is controlled by the polarization direction of the polarization exposure in a very short time with a high efficiency. In addition, there is an effect that it can be formed with good uniformity.

[Brief description of the drawings]

FIG. 1 is a conceptual cross-sectional view for explaining a chemical adsorption step used for producing a monomolecular liquid crystal alignment film in Example 1 of the present invention.

FIG. 2 is a conceptual cross-sectional view for explaining a cleaning step for producing a monomolecular liquid crystal alignment film.

FIG. 3 is a conceptual diagram in which a cross section is enlarged to a molecular level in order to explain a molecular alignment state in a monomolecular liquid crystal alignment film after solvent washing.

FIG. 4 is a conceptual diagram of an exposure step used to reorient molecules adsorbed by light exposure.

FIG. 5 is a conceptual diagram for explaining a molecular alignment state in a monomolecular liquid crystal alignment film after photo alignment.

FIG. 6 is a conceptual diagram in which a cross section is enlarged to a molecular level in order to explain a molecular orientation state of a chemically adsorbed monolayer after photo-alignment.

FIG. 7 is a conceptual cross-sectional view enlarged to a molecular level to explain a state in which a chlorosilane monomolecular film is formed (before reaction with moisture in the air) in Example 2 of the present invention.

FIG. 8 is a conceptual cross-sectional view enlarged to a molecular level for explaining a state in which a siloxane monomolecular film is formed in Example 2 of the present invention.

FIG. 9 is a conceptual cross-sectional view for explaining the manufacture of a liquid crystal display device in Embodiment 5 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Chemical adsorption liquid 3 Non-aqueous solvent for cleaning 4 Primary-oriented chemical adsorption monomolecular film 4 'Reoriented chemical adsorption monomolecular film 5 Direction of pulling up from cleaning liquid 6 Polarizing plate 7 Irradiation light 8 Reorientation direction Reference Signs List 9 transparent electrode 11 chlorosilane monomolecular film 12 siloxane monomolecular film 13 polarization direction 21 first electrode group 22 transistor group 23 first substrate 24 color filter group 25 second electrode 26 second substrate 27 liquid crystal alignment film 28 spacer 29 adhesive 30 liquid crystal 31, 32 polarizing plate 33 backlight

Claims (18)

[Claims] 1. A chemical adsorption solution prepared using a non-aqueous organic solvent and a silane-based surfactant in a dry atmosphere is applied to the surface of a substrate provided with an electrode. The surfactant molecules in the inside and the substrate surface are chemically reacted to bond and fix the surfactant molecules at one end to the substrate surface, and after a predetermined time has elapsed after the evaporation of the organic solvent is completed, the non-aqueous organic solvent is removed. A method for producing a liquid crystal alignment film, comprising a step of washing and removing an unreacted surfactant remaining on a substrate surface to form a monomolecular liquid crystal alignment film. 2. A chemical adsorption solution prepared using a non-aqueous organic solvent and a silane-based surfactant in a dry atmosphere is applied to the surface of the substrate on which the electrodes are formed, and after evaporating the organic solvent, a predetermined amount is further applied. React for a time, chemically react the pre-surfactant molecules with the substrate surface, bond and fix the surfactant molecules at one end to the substrate surface, and use a non-aqueous organic solvent to leave unreacted surfactant remaining on the substrate surface After washing and removing, the substrate is further set up in a desired direction to drain the washing solution, the fixed molecules are pre-orientated in the direction of drainage, and a monomolecular film in which the chemically adsorbed molecules are primarily oriented in a certain direction. Forming a liquid crystal alignment film. 3. The method for producing a liquid crystal alignment film according to claim 1, wherein an atmosphere having a relative humidity of 30% or less is used as the drying atmosphere. 4. A silane-based surfactant containing a linear carbon chain or a siloxane bond chain and at least one silyl group selected from a chlorosilyl group, an alkoxysilyl group and an isocyanatesilyl group is used as the surfactant. A method for producing a liquid crystal alignment film according to claim 1. 5. The method for producing a liquid crystal alignment film according to claim 1, wherein a mixture of a plurality of silicon-based surfactants having different critical surface energies is used as the surfactant. 6. A terminal or a part of a carbon chain or a siloxane bonding chain has a carbon trifluoride group (—CF ₃ ), a methyl group (—CH ₃ ), a vinyl group (—CH ＝ CH ₂ ), an allyl group ( —CH ＝ CH—), acetylene group (carbon-carbon triple bond), phenyl group (—C ₆ H ₅ ), aryl group (—C ₆
H ₄ —), a halogen atom, an alkoxy group (—OR; R represents an alkyl group), a cyano group (—CN), an amino group (—NH ₂ ), a hydroxyl group (—OH), a carbonyl group (＝ C
The method for producing a liquid crystal alignment film according to claim 4, wherein the organic compound is substituted with at least one organic group selected from O), a carboxy group (—COO—), and a carboxyl group (—COOH). 7. The method for producing a liquid crystal alignment film according to claim 1, wherein a step of exposing through a polarizing plate is performed after washing or preliminary alignment. 8. When exposing through a polarizing plate, a pattern-shaped mask is overlapped and exposed to form a plurality of portions having different pattern-oriented directions in an orientation film in the same plane.
3. The method for producing a liquid crystal alignment film according to item 1. 9. A silane-based surfactant containing a linear carbon chain or a siloxane bond chain and at least one silyl group selected from a chlorosilyl group, an alkoxysilyl group and an isocyanatesilyl group is used as the surfactant.
The method for producing a liquid crystal alignment film according to any one of claims 1 to 8, wherein a non-aqueous organic solvent containing substantially no water is used as the washing organic solvent. 10. The liquid crystal alignment film according to claim 9, wherein a solvent containing at least one organic group selected from an alkyl group, a carbon fluoride group, a carbon chloride group and a siloxane group is used as the non-aqueous organic solvent. Production method. 11. The method according to claim 1, wherein a step of forming a coating containing a large number of SiO groups is performed before the step of fixing the surfactant molecules at one end, and a monomolecular film is formed through the film. 11. The method for producing a liquid crystal alignment film according to any one of items 10 to 10. 12. A non-aqueous organic solvent and a silane-based organic solvent are prepared in a dry atmosphere by preparing a first substrate having a first electrode group previously mounted in a matrix and directly or after forming an arbitrary thin film. A chemisorption solution prepared using a surfactant is applied to the surface of a substrate provided with electrodes, and the surfactant is chemically reacted with the surfactant molecules in the adsorption solution and the substrate surface while evaporating and concentrating the organic solvent. The agent molecules are bound and fixed to the substrate surface at one end, the unreacted surfactant remaining on the substrate surface is washed away using a non-aqueous organic solvent, the substrate is set up in a desired direction, and the washing solution is drained. Preliminarily aligning the fixed molecules in a draining direction, exposing through a polarizing plate, and having a first substrate and a second substrate having the first electrode group, or a second electrode or an electrode group A second substrate,
Manufacturing a liquid crystal display device including a step of injecting and fixing a predetermined liquid crystal between the first and second substrates while aligning and fixing the liquid crystal display while maintaining a predetermined gap with the electrode surface inside. Method. 13. A non-aqueous organic solvent and a silane-based organic solvent are prepared in a dry atmosphere by preparing a first substrate having a first electrode group previously mounted in a matrix and directly or after forming an arbitrary thin film. A chemical adsorption solution prepared by using a surfactant is applied, and after evaporating the organic solvent, a reaction is performed for a predetermined time, and the surfactant molecules are chemically reacted with the substrate surface to cause the surfactant molecules to react with the substrate. Attach and fix to the surface at one end, wash and remove unreacted surfactant remaining on the substrate surface using a non-aqueous organic solvent, set up the substrate in a desired direction, drain the cleaning solution, Pre-aligning the fixed molecules, exposing through a polarizing plate, a first substrate and a second substrate having the first electrode group, or a second substrate having the second electrode or the electrode group To
Manufacturing a liquid crystal display device including a step of injecting and fixing a predetermined liquid crystal between the first and second substrates while aligning and fixing the liquid crystal display while maintaining a predetermined gap with the electrode surface inside. Method. 14. The method according to claim 12, wherein an atmosphere having a relative humidity of 30% or less is used as the drying atmosphere. 15. The method according to claim 15, wherein in the step of exposing through a polarizing plate, a patterning mask is superposed on the polarizing plate and exposed, and a plurality of portions having different patterning orientations are provided in an alignment film in the same plane. Item 15. The method for manufacturing a liquid crystal display device according to any one of Items 12 to 14. 16. The method for manufacturing a liquid crystal display device according to claim 12, wherein a silicone-based solvent is used as the non-aqueous organic solvent. 17. A non-aqueous organic solvent having a boiling point of 10
The method for manufacturing a liquid crystal display device according to claim 12, wherein a solvent at 0 to 250 ° C. is used. 18. The step of applying a chemical adsorption liquid,
The method for manufacturing a liquid crystal display device according to any one of claims 12 to 17, wherein offset printing, screen printing, or a roll coating method is used.