JPS6024447B2 - How to align the LCD - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electro-optical devices using liquid crystals, and more particularly to methods of aligning liquid crystals in such devices.

In the field, perpendicular to the surface of the substrate,
Alternatively, it is desired that they be uniformly aligned slightly at a corner from the vertical direction.

Prior art methods for liquid crystal alignment include the use of either soluble ionic alignment agents or polymeric surface coatings.

Ionic alignment agents are, for example, published by Ha on April 18, 1972
No. 5,658, to Iller et al. Alignment of liquid crystals by the use of polymeric surface coatings was described by Dubois et al., Appl. Phys. Le
tt. 24, 297 (1974). An undesirable characteristic in the case of ionic alignment agents is that the final mixture becomes electrically conductive, and devices fabricated using polymeric surface coatings exhibit slow response and lack alignment stability. It has been known. The present invention allows for the production of improved electro-optic devices that do not have the undesirable properties mentioned above. According to the invention, silicon dioxide is coated directly or over a previously coated indium-tin oxide coat on a surface for forming an electro-optical element. To induce liquid crystal alignment, the coated surface is treated with a mixture of aliphatic alcohol and amine, this treated surface is then cleaned with an inert organic solvent, and then the liquid crystal is placed in contact with this surface. Ru.

An advantage of the present invention is that it obtains liquid crystal alignment approximately perpendicular to the coating surface (homeotropic) without increasing the conductivity of the liquid crystals and without changing their properties in any way.

The present invention also eliminates the need to form a relatively thick polymer coating on the surface. It has now been found that liquid crystals aligned on coated surfaces treated according to the invention are more stable than such alignments according to prior art processes. In order to achieve a slightly tilted uniform alignment of the liquid crystals away from the vertical direction, the coating surface is ion beam etched at a narrow angle before being treated with a mixture of aliphatic alcohol and amine.

When the substrate surface treated by Sj02 is treated with a mixture of amine and long mirror aliphatic alcohol, the RO from the alcohol is responsible for the orientation of the liquid crystal to undergo orientation perpendicular to the surface of the coated substrate. It was found that there was a residual surface coating consisting of groups. Accordingly, the present invention provides a mixture of a most chain aliphatic alcohol and an amine, places a coated substrate of Si02 within the alcohol-amine mixture, and deposits from about 6 to 20 mm over a period of at least several minutes, preferably from 1 to 24 hours. Heat the same at a temperature of This is implemented by disposing a liquid crystal.

A preferred alcohol has the structure CH3(CH2)nCH20
days, where n is equal to 10 or 10
It is larger than. It is preferred to use 1-octadecanol, 1-hexadecanol, 1-tetradecanol, and 1-dodecanol because these alcohols are quickly activated. Closest chain alcohols are acceptable, but are generally more expensive and less readily activated. Short chain alcohols are undesirable if true vertical alignment is desired, and in fact 1-dodecanol is at the limit for some liquid crystals. However, short mirror alcohol can be used for certain liquid crystals. n is 4 when the liquid crystal is p-methoxybenzyldene-p-n-butylaniline.
It is also possible to make it smaller. Most aliphatic amines are applicable to the present invention, as long as they do not contain groups that act to reduce the basicity of the amine. Primary amines are preferred, and indeed amines that have low volatility at the temperature at which the treatment is carried out are preferred.
Satisfactory amines include 1-octadecylamine, 1-hexadecylamine, 1-tetradecylamine, 1-dodecylamine, didodecylamine, tridecylamine, N-methyloctadecylamine, N,N-dimethyloctadecylamine, and the like. including. It is recalled that the substrate is composed of a piece of solid silica.

However, in reality, in most liquid crystal devices, an electric field is applied through a liquid crystal layer or film, so the substrate is generally a transparent electrode with a thin upper layer of silica. For example, such an electrode may consist of a glass plate having an indium-tin oxide coating on at least a portion of its surface and a top coat of Si02 thereon with a thickness of about 100 angstroms to several thousand angstroms. be able to.

Such thin, transparent Si02 coatings can be deposited by conventional radio frequency plasma techniques. For other applications, it is desirable to apply Si02 surface coatings on mirror surfaces or other substrates.
The composition or structure of the substrate other than the silica surface is not important to the invention. The treatment is believed to cause a reaction between the alcohol and hydroxyl groups on the silica surface, with the amine acting as a catalyst for the reaction.

This can be expressed by the following equation. In the above formula, the silicon atoms are part of the silica surface and are attached to other atoms in the silica coating. Temperatures of 60:00 or above are used, but the treatment is limited in effectiveness at 60:00.

Temperatures in excess of 100° C. are preferred, and the water shown as a by-product in the above formula will likely evaporate and escape from the alcohol-amine mixture.

The upper temperature range is not critical unless it is so high that significant temperature decomposition or oxidation of the organic components of the mixture occurs. Temperatures in the range 1000 to 150 qo are suitable.

If processing is carried out in an open vessel, the actual upper temperature limit is the boiling point of the mixture. Air exclusion is not normally required, but such exclusion prevents oxidation of the organic elements. In hot alcohol-amine mixtures, substrate alignment effects are observed in as little as 15 minutes at 60 qo.

However, it is preferred to continue the treatment for at least 1 hour to ensure that a significant portion of the reaction surface locations are reacted. Obviously, a desired amount of time is required to complete the reaction, which is a function of temperature and concentration of alcohol and amine. It is convenient to use mixtures of alcohols and amines without any solvents or non-reactive diluents, but it is not impossible to use such solvents or diluents.

Obviously, the reaction will proceed rapidly if no solvent or diluent is used. The ratio of alcohol to amine is not critical. Preferably, approximately equal molar amounts of alcohol and amine are involved, since the reaction likely involves one molecule of alcohol and one molecule of amine that causes a change in one surface location. If the molecular weights do not differ significantly, it is easy to use equal amounts by weight. An alignment effect is also observed when no amine is used, but this effect is marginal and it is preferred to use sufficient amounts of amine. The treated substrate is washed with common inert organic solvents that are soluble in alcohols and amines.

Generally, a hydrocarbon solvent such as hexane is used as the primary solvent. Alcohol solvents such as methanol or ethanol help remove excess alcohol and amines. Other solvents such as ketone solvents, aromatic solvents, hydrocarbon chloride solvents, and the like may also be used. The composition of the liquid crystals is not the subject of this invention except that short chain alcohols can be used with some liquid crystals as mentioned above.

Nematic mixtures of esters are used in most of the methods, but they are not essential. If cholesteric liquid crystals are used, the alignment effect is such that the axes of the helices are oriented parallel to the surface. If the liquid crystal is a smectic material, the molecular axes are oriented substantially parallel to the surface. The vertical or homeotropic alignment of nematic liquid crystals is however most important. The liquid crystal can contain various dopants if desired. The following several examples are given to illustrate the practice of the invention. Example 1 A glass plate coated with indium-tin oxide is cleaned with inbropyl alcohol degreaser, etched with chromic acid, and rinsed with water and traene.

The cleaned indium tin oxide surface is overcoated with Si02. These substrates contain 1-hexadecanol and 1-hexadecylamine in a weight ratio of 1:
1 in a mixture as follows. That is, 1
000 to 130℃ for 1 hour, 105oo for 15 hours,
And it is 5 hours from 1050 to 125o0. These are then washed through acetone, methanol, and '3' hexane and dried. Cells are 2-butoxyphenyl 2-butoxybenzoate, 2-butoxyphenyl IZ-hexyloxybenzoate, 1
A nematic mixture was composed of -butoxyphenyl IZ-octyloxybenzoate and 2-butylphenyl P-toluate in a weight ratio of 5:9:9:15, respectively. The liquid crystal contained a thin layer between two treated substrates separated at the periphery by a 1'2 mil Mylar standoff. The cells were examined by polarized light microscopy and the optical axis, coinciding with the long axis of the molecules, was confirmed to be aligned perpendicular to the surface of the substrate. A minimal amount of light was only transmitted through the cell between the crossed polarizers, and the amount of transmission remained constant as the cell was rotated. Example 2 A transparent Sj02 upper cloud pole similar to that disclosed in Example 1 was heated with each of the following materials and used for the preparation of liquid crystal cells.

A cell was prepared with a liquid crystal mixture similar to that disclosed in Example 1, except that the conductive dopant, tetraethylammonium, was saturated. This dopant does not affect liquid crystal alignment. A 1/2 mil thick Mylar standoff was used. Inspection using a polarizing microscope revealed the following results. Cell A: with good vertical alignment,
It is pitch black between the crossed polarizers.

Cell B: mirrors in very different directions, but the alignment is close to vertical.

There are various shades of gray between the crossed polarizations.

This is the limit for vertical alignment.

Cell C: Same as cell B.

Cell D: Non-vertical alignment, light color between crossed polarizers.

The orientation of the liquid crystal is similar to that obtained on untreated substrates.

Cell E: Vertical alignment when first observed.

The alignment after 6 days is very large in various directions. I tilted the mirror.

Cell F: Similar to cell D with non-vertical alignment.

These results teach that 12 carbon alcohols are the critical chain length for vertical alignment and that long chain aliphatic alcohols are superior. They also have both primary and secondary amines capable of acting as catalysts;
We also show that some alignment effects can also be obtained by heating the substrate with amine-free long-chain aliphatic alcohols. Treatment with amine alone shows no alignment effect. Example 3 Transparent electrodes similar to Example 1 and having a 1500 angstrom thick coating were treated for 1 hour in a 1:1 weight ratio mixture of 1-hexadecanol and 1-hexadecylamine at various temperatures. Ta.

The electrode was then cleaned with methanol and hexane,
It was then used to adjust liquid crystal cells. The liquid crystal is similar to that used in Example 1 except that it contains a dopant of hexadecyltrimethylammonium stearate at a level equal to 20% of saturation at room temperature. This dopant is also an alignment agent, but the alignment effect at this concentration is small. The temperatures are as follows.
550-6 and ○ 790-85q ○ 10 is ○ 1170-121°C 13830 When the cells were viewed through a microscope between crossed polarizers, they appeared as patterns of different shades of gray and were tilted in different directions. expressed.

The clumps are less in electrodes treated at high temperatures;
The greatest difference was seen between cells treated at 79o to 85qo and 102°C. It was concluded that the treatment is preferably carried out at temperatures above 100°C. Example
4 An electrode similar to that disclosed in Example 1 was heated with a 1:1 weight ratio mixture of hexadecanol and hexadecylamine for about 1 hour and then washed with methanol and hexane.

A liquid crystal cell was constructed using a liquid crystal mixture similar to Example 1 except that it was approximately 50% saturated with tetrabutylammonium sulfonated trifluoromethane. This is an electrolytic dopant that is not inductively aligned, and the liquid crystal mixture is not vertically aligned on the untreated substrate, but shows an irregular orientation parallel to the surface.
In the cells of the treated electrodes, the liquid crystals were vertically aligned with little or no nuisance and no alignment defects. Example 5 Transparent Si02 top coated electrodes similar to those disclosed in Example 1 were heated in the following mixture and treated with N-(p-methoxybenzene) containing 0.05% by weight of tetrabutylammonium perchloride. p-n-butylaniline was used for the preparation of liquid crystals.

Alcohol, Temperature, Time, Weight, Weight, Time, and Weight to the Head of the Cell.) GC] 0:00A I-Tetradecanol 116-123 208
1-Dodecanol 1.16-123
20C I-decanol 11.6~1
23 20D I-nonanol 110-140 2
3 ears I-octanol 110-140 23F
I-hebutanol 110-140 23G I-
Hexanol Ko1570* 20th I-Pentanol Ko1380* 201 1-Pentanol
Two 1180* 8* markings suitable for repeated temperature cells A to G of the mixture were aligned substantially vertically.

The liquid crystal in the cell markings was substantially tilted significantly from the vertical, and the liquid crystal in cell 1 was hardly aligned. For reliable applications (e.g. television projection displays or light valves), it is desirable to be aligned almost perpendicular to the surface of the substrate, or evenly tilted slightly away from the vertical. .

The present invention naturally obtains such a tilted vertical alignment;
Furthermore, it allows precise and reproducible control of the tilt angle. Liquid crystal molecules can be aligned almost perpendicular to the surface, except that they are tilted slightly in a single direction in the absence of an electric field. When an electric field is given,
The liquid crystal molecules are further tilted in the same direction. S aligned diagonally
Ion beam etching with argon ions can be used to obtain the i02 surface. The ion beam angle with respect to the surface should preferably be between 10 and 300 degrees. The surface is then treated with a mixture of aliphatic alcohols and amines, preferably at temperatures above 10,000° C. for more than 4 hours, especially at 120° C. for 12 hours to 2 yolks. Substantially complete reactions are desirable with reproducibly controlled tilt angles. The time required for the reaction to complete is a function of temperature and alcohol and amine concentrations. Alcohol has the structural formula CH8 (
CH2) nCH20 days, where n is equal to or greater than 10.

Short chain alcohols can be used for some mixtures or for some liquid crystal mixtures to obtain large tilt angles, but in general alcohols of 10 or more carbons are suitable for tilt angles of 1oo or less. is sufficient for acquisition and in most practical applications.
Alcohols with 18 or more carbon atoms tend to yield very small anclination angles, which are less desirable.

However, if true vertical alignment is desired, they are useful as described above. Suitable amines include 1
-octadecylamine, 1-hexadecylamine, 1-
These include tetradecylamine, 1-dodecylamine, didodecylamine, tridodecylamine, N-methyloctadecylamine, N,N-dimethyloctadecylamine, and the like. It has been found that when a liquid crystal cell is made by joining two surfaces treated as disclosed with a thin layer of liquid crystal between them, the liquid crystals are in a back-slanted vertical alignment throughout the cell. Ta.

However, the surface needs to be ion beam etched in the reaction direction. This is shown in FIG.
FIG. 1 shows the regular processing method, and the arrows in the la diagram indicate the etch direction. An oblique vertical alignment was obtained in the treated cells of the lb diagram. If the cell is processed with etched surfaces in the same direction, uniform mirror skew will not occur throughout the cell.

The irregularity processing method is shown in FIG. FIG. 2 shows the irregular processing method, with the arrow in FIG. 2a indicating the etch direction. In the treated cell shown in Figure 2b, a liquid crystal orientation as shown in the figure was obtained.

When an electric field is applied across the liquid crystal of FIG. 1, the molecules are all tilted in the same direction.

When the fin boundary is given to intersect with the liquid crystal in Figure 2, there is a tendency in a certain plane to tilt the liquid crystal in one direction,
At the same time, there is a tendency to tilt in the opposite direction on other surfaces. In fact, the liquid crystal tilts in different directions with a swirl in an amount that matches the difference. As shown in Figure 3,
The tilt angle away from the perpendicular, defined by the substrate normal and 8, is an important characteristic in some liquid crystal devices.

Here, the solid line in FIG. 3 indicates the direction of liquid crystal molecules. The tilt angle is a characteristic of the transmission of light through an element consisting of cells sandwiched between crossed polarizers, specifically at an angle of 45 degrees with respect to the oblique direction. the transmission of light when the plane of polarization passes through each polarizer, {2) the stiffness of the response curve as the voltage increases and passes the threshold voltage, the rigid response time, and ( 4} the ability to prevent slopes in opposing directions at the edges of a given electric field in which the lateral component is present.

In application of the above observation as a criterion for determining changes in the tilt angle, the tilt angle for a given liquid crystal structure increases with decreasing carbon chain length of the alcohol used in the alcohol-amine treatment. It was discovered that

For a given alcohol-amine treatment, the oblique angle is related to the liquid crystal or to the components of the liquid crystal mixture, including the daub material. The orientation of liquid crystals at the surface is described by Kahn, Ta
ylor, and ShoMom [IM. Cit. ] and others, it is believed to be a function of both the surface tension of the liquid crystal (yL) and the critical surface tension of the solid (yc). However, despite a single orientation either parallel or perpendicular to the surface, the forehead-oblique azimuth direction can also exceed a narrow range of values of yc for a given value of yL. be. Changes in the length of the alkoxy groups attached to the surface can lead to minute changes in yc and, as a result, make minute changes in the tilt angle. Conversely, for a given value of yc, minute changes in the mirror oblique angle can be made by making small changes in the liquid crystal composition. Although the configuration of the liquid crystal is not the subject of the present invention, the liquid crystal configuration and surface treatment must be matched to obtain the desired oblique angle. An attempt was made to measure the oblique angle of a mirror-tilted vertically aligned nematic liquid crystal.

This measurement is made by the difference in transmitted light passing through a transparent liquid crystal cell placed between a pair of crossed polarizers.
This device is illustrated in FIG. Figure 4a is a side view;
10 is a light source, 12 is a polarizer, 14 is a liquid crystal cell, 16 is an analyzer, and 18 is a photodiode detector. FIG. 4b is an end view showing a plane view of the polarization and oblique directions, and 20 indicates a polarizer, 22 an analyzer, and 24 the oblique direction in the liquid crystal cell.
The cell is also rotated so that the tilted molecules lie in a plane perpendicular to the axis of rotation.

Theoretically, when light passes through a cell parallel to the optical axis (which is the same as the molecular axis), the transmitted light has a length of 4. By measuring the angle of cell rotation that reaches this maximum, the oblique angle can be determined. Due to the difference between the refractive index of the liquid crystal and the refractive index of the air, the oblique angle is approximately 2/3 of the angle of cell rotation.
becomes. Data are obtained by these measurements that, when measurement errors are allowed, are in agreement with the abundance observations.

The buccal oblique angle increases as the alcohol chain length decreases. The following examples are given for a practical illustration of the invention. Example 6 Photoconductive electrodes and counter electrodes for a liquid crystal light valve were fabricated by sputtering a thin layer of Si02 (2
700 angstroms) was topcoated.

The electrode was placed at ground potential during sputtering and an argon atmosphere was used. The resulting Si02 surface was ion beam etched with an angle of 200 formed by the beam and the surface. These electrodes were used to make light valves first without surface treatment with alcohol and amine and then after alcohol-amine treatment. When light valves were first created, a liquid crystal composed of four phenylbenzoate esters was used;
The mixture is then saturated with the vertical alignment agent hexadecyltrimethylammonium stearate.

The electrode is made of Si with a thickness of 2 microns around the green part of the counter electrode.
02 separated by a separating material. When the light valve was first activated with crossed polarizers by the projection beam, only half of the cells were aligned nearly perpendicular (homoetropic alignment) and the rest were aligned nearly parallel (homogeneous alignment). It was observed. During the first few minutes of operation, the areas were loosely aligned perpendicular to the dimension and soon the entire cell was permanently aligned in parallel. Aligning agents were ineffective in this thin cell. The cell was isolated and the electrodes were cleaned with hexane and methanol to remove the liquid crystals.

They were then mixed with 12
000 for approximately 18 hours. After treatment, unreacted alcohol and amine were removed by washing through hexane and amine again. The cell was reconditioned using a liquid crystal mixture similar to that used before, but only half saturated with hexadecyltrimethyl-asomonium stearate. The stearate is ineffective as an alignment agent in this case, but acts as a conductive dopant. During cell operation, the liquid crystals were found to be well aligned in an orientation that was virtually indistinguishable from vertical (homoetropic) alignment. However, it was shown that the liquid crystal molecules all tilted in the same direction when an electric field was applied, resulting in an oblique vertical alignment. No alignment changes occurred during several hours of light valve activation. Example 7 A light valve similar to Example 6 including alcohol-amine treatment was constructed.

The electrodes were ion beam etched in the same direction on both sides and placed relative to each other in the manner described above. When the cell was driven through crossed polarizers by the projection beam, a black line appeared across the projected image on the screen. These black lines correspond to the positions of the light valve where the slope of the liquid crystal is parallel to the plane of polarization of either the polarizer or analyzer. This indicates that the liquid crystal tilts in various directions in a given electric field. The cell is realigned by reversing one electrode so that the etching on the two surfaces is not in opposite directions. Now, no black lines appeared in the image area, and the characteristics were uniform under conditions where the electric field was uniform. This shows that the molecules are tilted in a uniform direction by the electric field, and that the tilt is therefore uniform in orientation even in the off state. Example 8 An indium-tin oxide coated glass plate was cleaned with inpropyl alcohol degreaser, etched with chromic acid, and rinsed with water and transene.

This cleaned indium-tin oxide surface is Si02
and etched with an ion beam through a narrow angle as disclosed in Example 6. These samples were then injected into a 1:1 mixture by weight of primary alcohol and 1-hexadecylamine.
Heated for 17 hours at ○±100°C. The treated surface was washed through hexane and methanol. A transparent cell was constructed by using a 1/2 mil thick Mylar standoff and a 4-component ester liquid crystal mixture (HRL-10). The inclination angle is
It was then determined by an apparatus similar to that shown in FIG. The table below shows the alcohols used and the results obtained approximately one week after the cells were made. alcohol
Inclination angle 1-octade force/r 0.2 1-hexadecanol 0.5 1-tetradecanol 0.3 1-dodecanol 3.7 1-decanol 6.5 Short-chain alcohols tend to have large oblique angles is clear.

The measurement error is estimated to be approximately 0.20. Example 9 This example describes an alcohol-amine treatment that produces sufficient phasic gradients so that liquid crystal mixtures can also produce large gradients within different mixtures.

Photosensitive light valve substrate with Si02 top coating and S
The i02 top overcoat counter electrode was subjected to narrow angle ion beam etching as disclosed in Example 6.

These range from 1150 to 1 in a 1:1 weight ratio mixture of 1-tetradecanol and 1-hexadecylamine.
25 qo for one period and then washed through organic solvent to remove unreacted alcohol and amine. The counter electrode has a 2 mm thick Si02 spacer at its periphery. The cell was first constructed using a mixture of 6 phenylbenzoate esters (HRL-13).

The light valve has good contrast when images are projected by crossed polarizers. The cells were kept spaced and the electrodes were cleaned with an organic solvent to remove the liquid crystal. The electrode was then used again to make a light valve with another liquid crystal mixture (HRL- of 12), missing one of the 6-esters by the amount that HRL- differed from 13. The low contrast was obtained because the device transmits enough light in the off state. Also, the threshold of the transmitted light versus voltage curve is not very sharp. These properties should result in a sufficiently large gradient in the alignment of the liquid crystals. again,
The cell is disassembled and cleaned, and the electrodes are HRL-
13 were reused to make light valves. High contrast was again obtained, demonstrating no change in alignment despite cell separation, electrode cleaning, and cell disassembly techniques. Example 10 This example illustrates the use of a mixture to obtain the correct degree of oscillation in alignment.

Three similar Si02 top-coated photosensitive light valve substrates and counter electrodes were narrow-angle ion beam etched as disclosed in Example 6 and amines made up of half the weight of the mixture in each case. with a mixture of alcohol and 1-hexadecylamine.

This treatment was carried out for 16-21 hours at 1170-136]. The cell contains 2:1 N by weight with addition of 0.05% by weight tetrabutylammonium perchlorate.
-(p-toxybenzylidiene) was constructed using a mixture with p-butylaniline (M former BA). (The liquid crystal is aligned parallel to the surface that does not undergo the alcohol-amine treatment.) This cell operated in the same way as crossed polarizers in the projection beam. The images are compared due to the "black line edge effect", which is caused by the edges of the shape formed by the applied electric field being tilted in different directions. These black line edge effects are probably influenced by the lateral component of the electric field. The results are shown in the table below. EXAMPLE 11 A transparent Si02 topcoat electrode, previously etched as taught in Examples 6 and 8, was heated in each of the following alcohol-amine mixtures and 0.05% by weight of tetrabutylammonium perchlorine. N-(p-methoxybenzyldine)-p-n-butylaniline containing acid salts are used to prepare liquid crystals.

*mark is the cyclic temperature of the mixture.

Cells A through G exhibited measured tilt angles of 0.50 or less.

The cell date showed an oblique angle of 040.

[Brief explanation of the drawing]

FIG. 1 shows a regular processing method, where the la diagram shows the etching direction and the lb diagram shows the alignment of liquid crystal molecules. FIG. 2 shows the irregular processing method, where FIG. 2a shows the etching direction and FIG. 2b shows the liquid crystal orientation. FIG. 3 shows the orientation of liquid crystal molecules relative to the substrate vertical. Figure 4 shows
FIG. 4a shows a side view of the arrangement, and FIG. 4b shows an end view of the nematic liquid crystal forehead oblique angle measuring device. The correspondence of reference numbers in the figure is as follows. 10: light source, 12: polarizer, 14: liquid crystal cell, 16: analyzer, 18: photodiode detector, 20: analyzer direction, 22: polarizer direction, 24: nostalgic direction in the liquid crystal cell. Fig. lo Atsushi lb Fig. 2 o Fig. 2 b Fig. Fin S Fig. 4 G Fig. 4 b

Claims (1)

Claims: 1. Silicon dioxide directly or overlying a previously applied indium-tin oxide coating on a surface to form a coated electro-optical element; A method for inducing desired liquid crystal alignment, comprising the steps of: treating the coated surface with a mixture of an aliphatic alcohol and an amine; and cleaning the treated surface with an inert organic solvent. and arranging liquid crystals in contact with the cleaned surface. 2. The method according to claim 1, wherein the alcohol-amine mixture has the structural formula CH_3(CH_
2) A process consisting of an aliphatic alcohol of the formula _nCH_2OH, where n is equal to or greater than 4, and an aliphatic amine. 3. The method of claim 2, wherein the alcohol-amine mixture is comprised of approximately equal weights of alcohol and amine, and wherein n in the structural formula is greater than or equal to 10. How to use. 4. The method according to any one of claims 1 to 3, wherein the liquid crystal contains a conductive dopant. 5. The method according to any one of claims 1 to 4, wherein the amine is 1-hexadecylamine, and the liquid crystal is N-(p-methoxybenzyldine)-p -n-butylaniline. 6. The method according to claim 1, wherein the alcohol-amine mixture has the structural formula CH_3(CH
_2)_nOH and an alcohol with n equal to or greater than 3 and having the structural formula CH_3(
CH_2)_nCH_2NH_2 and n equal to or greater than 2 in equal parts by weight of a primary amine.