CN1026364C - Process of aligning liquid crystal media - Google Patents
Process of aligning liquid crystal media Download PDFInfo
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- CN1026364C CN1026364C CN 90107239 CN90107239A CN1026364C CN 1026364 C CN1026364 C CN 1026364C CN 90107239 CN90107239 CN 90107239 CN 90107239 A CN90107239 A CN 90107239A CN 1026364 C CN1026364 C CN 1026364C
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Abstract
The present invention discloses a method for orientating and ranging molecules in a liquid crystal medium whose surface is press close to a base sheet, wherein when the molecular weight of liquid crystals is smaller than 1500, each anisotropic absorption molecule in the medium or the base sheet press close to the medium is exposed by linear polarized light, and light wavelength is in an absorption band of the absorption molecule. Through each exposed anisotropic absorption molecule, the liquid crystal medium is induced to be orientated and ranged into the angle of +theta or-theta with the linear polarization direction of an incident light beam.
Description
The present invention relates to the process of aligning of anisotropic molecule in a kind of liquid crystal media.
Liquid-crystal compounds is used for the display device of people and mechanical-readable, for example, is used for instrument controller spare and the process control device and the time set (as clock and watch) of automobile.This display device is clipped in glass or other transparent substrate to form a box with liquid crystal media basically, optionally coats transparent conductive material so that the imaging figure of conduction to be provided on two substrates.
The transmittance of these liquid crystal cells can be easily be controlled with the method that changes the liquid crystal media orientation, makes fully, part or do not have available light to see through.By liquid crystal cell being applied voltage or magnetic field, can make the liquid crystal media orientation.Can also use one or two polarizer to control the transmittance of the liquid crystal media of orientation.
Liquid crystal media can also contain the anisotropy dyestuff of dissolving except that liquid crystal.By one or more liquid-crystal compoundss be dissolved in this medium that one or more dyestuffs wherein constitute and be called " host and guest " system.
The anisotropy dyestuff that is suitable for most display in " host and guest " system is a dichroic dye, and this dyestuff is more along the light that an axle absorbs, and less along the light of second axle absorption.When liquid crystal main body composition be dissolved in wherein object dyestuff and mate when suitable, the orientation of this potpourri can be controlled by the voltage that applies, thereby only sees through the light of requirement.
The component of these displays is considered to anisotropic, because the numerical value difference of the character that they demonstrate when measuring along disalignment (a) (b) is taked different positions with environmental stimuli, for example, impressed voltage can make liquid crystal center on the stationary shaft rotation, and the result changes its optical property.More particularly, they are birefringent.
In the liquid crystal cell that present commodity use, molecular orientation is taked to be parallel to or perpendicular to the arrangement of substrate.When not having environmental stimuli, display or opaque, or transparent, the known method that has a lot of with the liquid crystal media orientations.Usually, the inside surface of transparent substrate is made of transparent oriented layer, and for example the film by poly-alkylsiloxane or lecithin constitutes.
For being arranged in parallel, in box that liquid crystal media is packed into before, with a piece of cloth along the assigned direction friction coatings, thereby optionally change surface state, the long molecular axis that makes liquid crystal along or be close to and be parallel to the frictional direction arrangement.After box was filled, this orientation was delivered in the body phase liquid medium by intermolecular force.
The characteristics of homeotropic alignment be liquid crystal long axis direction along or be close to the direction be parallel to the substrate vertical line, utilize the oriented layer of chemical modification usually or apply electric field and realize at the two ends of box.
Need a kind of simply to the method for liquid crystal media orientation or reorientation.In addition, preferably can provide a kind of liquid crystal cell, it has two or more zones with parallel or vertical different modes orientation, also wishes in some cases to eliminate the oriented layer that is used for LCD.
According to the present invention, a kind of method that makes the anisotropic molecule orientations in containing the liquid crystal media of liquid crystal is provided, the surface and the substrate of medium are pressed close to, described method is characterised in that, the molecular weight of liquid crystal is less than 1500, in the medium or the molecule of the anisotropic absorption in the substrate of pressing close to it linearly polarized photon is exposed, light wavelength is absorbing within the absorption band of molecule, the anisotropic absorption molecule of exposure brought out with respect to the linear polarization direction one-tenths+θ of incident beam or-liquid crystal media at θ angle is orientated.
" anisotropic absorption molecule " be meant compound along disalignment when measuring, demonstrate the optical absorption property of different numerical value.Term " liquid crystal " is commonly referred to as the molecule with anisotropy geometry, for example bar-shaped or dish type molecule, and their steady state (SS) is situated between between liquid and the solid, and its molecular weight is preferably 1000 or littler less than about 1500, is preferably 650 or littler.Liquid crystal media of the present invention can contain so any liquid-crystal compounds that is generally used in LCD and other liquid crystal device.Preferably with the thermotropic liquid crystal that presents nematic phase and smectic phase (comprising ferroelectric phase).
Nematic phase comprises common single axial row, twisted nematic and cholesteric mesomorphic phase.Nematic liquid crystal can have positive or negative dielectric anisotropy.Here used " just " and the finger of " bearing " contain the pure dielectric anisotropy of the potpourri of liquid crystal.
Being fit to implement the positive nematic phase liquid crystal material that obtains easily of the present invention comprises:
4-cyano group-4 '-alkyl biphenyl, 4-cyano group-4 '-alkoxy biphenyl, the 4-alkyl-(4 '-cyano-phenyl) cyclohexane, the 4-alkyl-(4 '-the cyanobiphenyl base) cyclohexane, 4-cyano-phenyl-4 '-alkyl benzoate, 4-cyano-phenyl-4 '-the alkoxybenzoic acid ester, 4-alkoxyl phenyl-4 '-the cyanobenzoic acid ester, 4-alkyl phenyl-4 '-the cyanobenzoic acid ester, 1-(4 '-alkyl phenyl)-4-alkyl pyrimidine, 1-(4 '-alkyl phenyl)-and the 4-cyanopyrimidine, 1-(4 '-alkoxyl phenyl)-4-cyanopyrimidine and 1-(4-cyano-phenyl)-4-alkyl pyrimidine.The instantiation that belongs to above-mentioned classes of compounds has:
4-cyano group-4 '-pentylbiphenyl, 4-cyano group-4 '-own oxygen base biphenyl, instead-the 4-amyl group-(4 '-cyano-phenyl) cyclohexane, instead-the 4-hexyl-(4 '-the cyanobiphenyl base) cyclohexane, 4 '-propylbenzoic acid-4-cyanobenzene ester, 4 '-cyanobenzoic acid-4-amoxy phenyl ester, 4 '-cyanobenzoic acid-4-hexyl phenyl ester, 1-(4 '-amyl group phenyl)-the 4-butyl pyrimidine, 1-(4 '-butoxy phenyl)-the 4-cyanopyrimidine, the 1-(4-cyano-phenyl)-and 4-alkyl pyrimidine, 4-n-hexyl benzal-4 '-aminobenzonitrile and 4-cyano group benzal-4 '-octyloxy aniline.
The eutectic mixture of above-mentioned all compounds and composition also can use.Example has 4 '-alkyl-4-cyanobiphenyl and 4 '-eutectic mixture of alkoxy-4-cyanobiphenyl (wherein 4 ' bit substituent has 3 to 8 carbon atoms) or terphenyl liquid crystal (alkyl or the alkoxy substituent that contain 3 to 8 carbon atoms are arranged on 4).Representational compound has BDH company (Poole, commodity E7 potpourri England); The ROTN404 of Hoffman La Roche company (Nutley, New Jersey), it is the eutectic mixture of biphenyl pyrimidine liquid crystal; The PCH1132 of EM Industries company (Hawthorne, New York), it is by potpourri that 4-alkyl-(4 '-cyanobiphenyl base) cyclohexane and 4-alkyl-(4 '-cyano-phenyl) cyclohexane is formed; And also be the commodity ZLI1982 of EM Industries company.
Can be used for the representative example with nematic liquid crystal of negative dielectric anisotropic of the present invention has:
4-alkoxy-4 '-the alkoxy azoxybenzene, 4-alkyl-4 '-the alkoxy azoxybenzene, 4-alkyl-4 '-the acyloxy azoxybenzene, 4-alkyl-4 '-alkyl azoxybenzene and 4-alkyl-2-cyano-phenyl-4 '-alkyl biphenyl base-1-carboxylate.Object lesson comprises:
To the azoxy methyl phenyl ethers anisole, 4-butyl-4 '-own oxygen base azoxybenzene, 4-butyl-4 '-the acetoxyl group azoxybenzene, 4,4 '-two (hexyl) azoxybenzenes and 4-amyl group-2-cyano-phenyl-4 '-heptyl xenyl-1-carboxylate.There are the Licristal S1014 of EM Industries company (Hawthorne, New York) and the EN-18 of Chisso company (Yokohoma, Japan) in the commercial goods.
Can be used for smectic A phase liquid crystal of the present invention, its medium anisotropy can be for just or for negative.Just anisotropic smectic A phase liquid crystal comprises: 4-alkyl-4 '-cyanobiphenyl and 4-cyano group-4 '-the alkyl benzalaniline, and the potpourri of 4-alkyl-4 " cyano group-para-terpheny and 4-alkyl-4 "-cyanobiphenyl.
Also can use by the smectic A phase mixture that mid-term, produced nucleus derived of accepting electronics and supply electronics, for example, 4 '-alkyl phenyl-4-alkyl benzoate and 4 '-cyano-phenyl-4 " alkoxy benzene formyloxy benzoic ether.The examples of compounds that can be used as the smectic A phase liquid crystal with positive dielectric anisotropy has: 4-cyano group-4 '-the octyl group benzalaniline, 4-decyl-4 '-cyanobiphenyl, 4-dodecyl-4 " cyano group-para-terpheny, 4 '-heptyl phenyl-4-butylbenzoic acid ester and 4 '-cyano-phenyl-4 " octyloxy benzoyloxy benzoic ether.The eutectic mixture and the composition of above-mentioned all smectic A phase materials all can use.The eutectic mixture of representational smectic A phase liquid crystal and composition are commercial goods material S1, S2, S3, S4, S5, S6 and the S7 of EM Industries company (Hawthorne, New York).
Can be used for the representative instance with smectic A phase liquid crystal of negative dielectric anisotropic of the present invention is:
4-alkyl phenyl-4-alkoxy-3-cyanobenzoic acid ester, 4-alkoxyl phenyl-4-alkoxy-3-cyanobenzoic acid ester and 4 " alkoxyl phenyl-4 '-alkoxy benzene formyloxy-3-cyanobenzoic acid ester.Object lesson comprises:
4 '-octyl phenyl-4-oxygen in last of the ten Heavenly stems base-3-cyanobenzoic acid ester, 4 '-last of the ten Heavenly stems oxygen base phenyl-4-octyloxy-3-cyanobenzoic acid ester and 4 '-heptan oxygen base phenyl-4 '-last of the ten Heavenly stems oxygen base benzoyl-3-cyanobenzoic acid ester.Their eutectic mixture also can use.
The representative example that can be used for implementing chiral smectic C phase liquid crystal of the present invention comprises: 4-alkoxyl phenyl-4-alkoxybenzoic acid ester, 4 '-alkoxy xenyl-4-alkoxybenzoic acid ester, 4-alkoxyl phenyl-4-alkoxy biphenyl carboxylic acids ester and 4 '-terpene alcohol ester of positive alkoxy xenyl-4-carboxylic acid.Object lesson is: phenyl-4-p-methoxybenzoic acid in last of the ten Heavenly stems ester own oxygen base of 4(4-methyl), 4-oxygen in the heptan base phenyl-own oxygen base of 4(4-methyl) benzoic ether, 4 '-octyloxy xenyl-4-(2-methyl butoxy) benzoic ether, 4-oxygen in ninth of the ten Heavenly Stems base phenyl-4 '-(2-methyl butoxy) xenyl-4-carboxylate and 4 '-n-octyloxy xenyl-4-carboxylic acid
Ester.
The potpourri of commercially available chiral smectic C phase liquid crystal comprises the CS1000 series that Chisso company (Yokohoma, Japan) provides; The ZLI4139 of EM Industries company (Hawthorne, New York); And the eutectic mixture of the BDH company pendant fluorinated ester class of producing and SCE3 to the SCE12 eutectic mixture that EM Industries company sells with SCE series.Based on 4 '-single component chiral smectic C phase material W7, W37, W81 and the W82 of alkoxyl phenyl-4-alkoxybenzoic acid ester can obtain from Displaytech company (Boulder, Colorado).
Prepared host and guest's prescription with all types of liquid crystal.The dyestuff that can be used in these potpourris comprises the dichromatism azo, gives birth to nitrogen, nitrine, bisdiazo, five nitrogen, anthraquinone, colour developing cyanine, methine, 2-phenylazo thiazole, 2-phenylazo benzothiazole, 4,4 '-two (fragrant azo group) Qi, perylenes and 4, the 8-diaminostilbene, 5-naphthoquinone dyestuff, and other dyestuff that demonstrates the bitintability absorption band.The bitintability absorption band is best to the dyestuff between about 2000 nanometers in about 150 nanometers.Some instantiations that can be used for the dyestuff among the present invention are listed in the example table before.
In the accompanying drawings:
Fig. 1 is the synoptic diagram of a typical liquid crystal cell.
Fig. 2 represents to be used for to a kind of device of liquid crystal media orientation or reorientation.
Fig. 3 is a front view that passes through host and guest's liquid crystal media of friction orientation already.
Fig. 4 is host and guest's liquid crystal media of Fig. 3 front view after with method reorientation of the present invention.
The most familiar liquid crystal device is a LCD.Fig. 1 has represented the synoptic diagram as a kind of basic liquid crystal cell of the working portion of this display.This synoptic diagram only illustrates usefulness, because method of the present invention is all suitable to the orientation of used liquid crystal media in all kinds of liquid crystal devices.
Liquid crystal cell shown in Figure 1 contains host and guest's liquid crystal media (4).Short-term is represented bulk liquid crystal molecules, and the object dye molecule is then represented with the line of two ends band circle.In Fig. 1, box has two substrates, scribble transparent conductive layer (for example tin indium oxide) (2) on the inward-facing surface of its critical part (1) (for example glass), scribble the oriented layer (3) that is made of organism (for example polyimide) film on the inward faces of this conductive layer again, it rubbed along straight line is unidirectional with polishing cloth.
The substrate that applied separates placement Face to face, and the thin glass fiber (not shown) that is about 2 to 20 microns with diameter is controlled it at interval.With for example epoxy resin (not shown) liquid crystal layer (4) is sealed.Among the figure+and-voltage that applies of representative.Liquid crystal cell can be with exchanging (AC) or direct current (DC) voltage power supply, and the voltage direction shown in Fig. 1 does not mean that the restriction to it.
With two or more this box combinations, can intensify.For example, can shared substrate, so that form so-called " three glass structures ".
The used light source of the present invention must be the linear polarization light source.In addition, the linear polarization light wavelength must be within the absorption band of anisotropic medium.Here refer to the absorption band of dyestuff in liquid crystal and the host and guest's liquid crystal media, or constitute the absorption band of the dyestuff (for example being coated on the substrate layer of liquid crystal media) of a substrate part as the dyestuff on conductive coating or the oriented layer.Usually, light should be in ultraviolet to infra-red range, because when expecting that the liquid-crystal compounds with in some cases has absorption peak in this scope.
Light wavelength is extremely better between about 2000 nanometers in about 150 nanometers.Light source is laser preferably, for example argon, He-Ne or helium cadmium laser.Use the laser instrument of lower-wattage may need light beam is focused on the box, but generally do not need light beam is focused on.
Method of the present invention can be used for making the liquid crystal media orientations of random orientation (isotropic) state, or makes (parallel or vertical) the liquid crystal media reorientation that has been orientated.If incident beam is vertical with substrate, its orientation effect will be by rotating exposure the geometric projection of major axis of anisotropic absorption molecule realize, this means that each molecule may be in the situation maximum of parallel-oriented molecule around the torque of minor axis, and along with the angle between substrate plane and the major axis increases and reduces, it closely is zero changeing weak point in the vertical orientated situation that is parallel to the incident beam polarization direction.Orientation by the liquid crystal that brought out of anisotropic absorption molecule of exposure probably also is like this.
The type of liquid crystal media preferably can be easily parallel-oriented the sort of type.Linearly polarized photon be applied to desire to make it to be orientated or the integral body or a part of the medium of reorientation on.Light beam can be fixed or rotation.Exposure can be a step exposure, the exposure of paroxysm formula or carry out with other method.Time shutter can be predicted altering a great deal of factor with material therefor and other, can from less than 1 second to above 1 hour.Skilled staff will be appreciated that, anisotropic absorption molecule and liquid crystal molecule with respect to incident beam linear polarization direction rotation+θ and-the θ angle is that bidimensional along a plane rotates.In general, in liquid crystal cell, this plane corresponding to define liquid crystal cell, with the surface of angled that substrate of incident light polarization direction.
Finish in the method for the present invention, should contact with liquid crystal media by at least one substrate.In general, liquid crystal media constitutes the part of the box with two this substrates, as shown in Figure 1.When adopting oriented layer, friction can improve performance usually, but and nonessential.
A key character of the present invention is that liquid crystal media has " memory " after finishing processing, that is, it will keep the orientation of being brought out by the linear polarization light source.Certainly, anisotropic medium also can become original or the third orientation with method reorientation of the present invention.In general, with the liquid crystal media of the inventive method orientations (and the box that makes by it) with identical with the display use-pattern of conventional method orientation.
The effect of the inventive method can be observed with polarizer.In other words, when having the liquid crystal cell of single polarizer, observe the highest absorption peak of dyestuff (or liquid crystal absorb, if only within the absorption band of liquid crystal) has an angle position with respect to background variation with one of white light.When with two sides of white light the liquid crystal cell of a polarizer being arranged respectively, observing in the exposure area has a change color with respect to background, and this angle position that shows liquid crystal molecule changes, and therefore variation has taken place in the birefringence of liquid crystal cell.This result is responsive to many factors, time shutter, intensity, wavelength and direction such as linearly polarized photon, the temperature of sample, used liquid crystal and dyestuff and ratio thereof, whether the existence of oriented layer, if have the type of oriented layer, and the position of anisotropic absorption molecule, quantity and character.
Has conventional display configuration (for example two, three or many substrate structures) with the LCD of the inventive method preparation, and can be normally used in prior art, comprise one or more polarizers, lighting device, reflection horizon, autoregistration reflection horizon, elastomer connector and circuit board.
In box, it is not necessary using conventional oriented layer, for example the polishing oriented layer that generally adopts in prior art.But when using soft wiping or friction orientation layer, under a lot of situations, performance can improve.Other oriented layer and method for alignment also can be in conjunction with using in the present invention.
Layer or its a part of reorientation that can will be in advance be orientated by soft wiping oriented layer of the present invention with method of the present invention.It should be noted that most that the one or more zones in the liquid crystal device can be orientated by being orientated different directions with remainder.This box can carry out reorientation by one or more zones of the liquid crystal media that will be orientated and prepare.Fig. 3 represents a liquid crystal main body medium that has been orientated in a certain direction.Fig. 4 represents that certain zone of this medium used method reorientation of the present invention.This figure has illustrated that liquid crystal molecule revolves the situation that turn 90 degrees with respect to incident light polarization direction and original orientation direction.
Another significant feature of the present invention is, this method can be finished by the anisotropic absorption molecule is added in the substrate, for example be added in organic material coating or that otherwise apply adjacent (as oriented layer or transparency conducting layer) with liquid crystal media, then, the anisotropic absorption molecule is exposed.This embodiment can be carried out with the liquid crystal media that contains the anisotropic absorption molecule, also can carry out with the liquid crystal media that does not contain this molecule.In addition, in these embodiments, can to the exposure of linearly polarized photon box-packed whenever carrying out before or after going into liquid crystal media.
Method of the present invention can be carried out under the condition that has electric field (direct current or interchange).But, not necessarily to there be electric field, in most of situations, this method is to carry out under the situation of added electric field not.
In general, the present invention is suitable for liquid crystal system orientation or the reorientation to being arranged in parallel most.But when being added with electric field, the homeotropic alignment liquid crystal with negative dielectric anisotropic enters the state of being arranged in parallel.This system of being arranged in parallel can be according to the present invention with polarized light oriented or reorientation.When removing electric field, liquid crystal reverts to the homeotropic alignment state usually.In this case, when applying electric field again, by bringing out of polarized light, liquid crystal can be orientated to the state of being arranged in parallel once more.
The conductive ion adulterant, chiral dopant, other materials such as light stabilizer and viscosity modifier also can use.Implement method of the present invention and might not need to add these materials.
Though the present invention describes according to the LCD box, should be clear, it can be used for other liquid crystal device, for example full optics photomodulator, erasable read/write optical data storage medium etc.
The present invention is illustrated with following example, and these examples are illustrative, is not construed as limiting the invention, and wherein all percentages are percent by weight.
What following table was listed is the dyestuff that uses in the example.
Example 1
This example is represented with method of the present invention host and guest's system reorientation that is made of the diazonium diamine dyes that is dissolved in the nematic liquid crystal.
The main body nematic liquid crystal is a ZLI1982(FM Industries company, Hawthorne, New York).Dissolved in the main body and accounted for liquid crystal weight 0.38%(weight) dyestuff 1.
With the 25%(weight of polyimide in 1-Methyl-2-Pyrrolidone (NMP)) solution to be diluted to the polyimide ultimate density with the NMP of SILVER REAGENT be 0.5%.This solution is placed on the top of tin indium oxide (ITO) layer of glass substrate part, placed 5 minutes, then substrate was rotated 30 seconds.Substrate is placed in the baking oven heating orientation coating is solidified, then with polishing cloth along the rectilinear direction cured coating that rubs.Then, place the glass fibre of 11 micron thickness on substrate, another substrate that has similar coatings is placed on its top, oriented layer constitutes the inside surface of gained box.With clip two substrates being pressed into spacing was 11 microns, is coated with epoxy resin along the edge, with epoxy resin cure 5 minutes.The space of the relative both sides of the edge of box stays open-ended.
Box is placed vacuum, and insert in host and guest's potpourri on unsealed one side.Box is filled by capillary action.After being full of, box taken out from vacuum wipe clean, seal with the space that epoxy resin will not seal.The polyimide that rubbed makes host and guest's material along the frictional direction orientations.
Device shown in Figure 2 (no optics lens) is used for host and guest's medium reorientation is arranged.Polarized light source is argon laser (model 2020-03, Spectra-Physics company, Piscataway, New Jersey), and its peak power is about 1.2 watts at 514.5 nano wave lengths.Laser is by being polarized of direction shown in two arrows among Fig. 2, by the camera shutter of a variable aperture, so that can control time shutter to sample.Shutter is set at manual control, needs the long time shutter because reorientation is arranged.When shutter opening, the laser beam that diameter is 4 millimeters is passed.This laser beam vertically is radiated on the plane of substrate as shown in Figure 2.
Fig. 3 and Fig. 4 represent liquid crystal cell with before the light beam exposure with the front view of later amplification.Before exposure, polarization of incident light direction (representing with two arrows) is parallel with the frictional direction of polyimide surface, and therefore, the major axis of dyestuff (line with the two ends zone circle is represented) and liquid crystal molecule (representing with line) also is like this.After exposure, find dyestuff in some microcell and liquid crystal molecule in the plane that the box substrate limits with respect to incident light polarization direction rotation+θ angle.In other microcells, dyestuff and liquid crystal molecule in the plane that the box substrate limits with respect to incident light polarization direction rotations-θ angle (rotation angle of mentioning later on all refers to the rotation in the plane of box substrate qualification).
When the θ angle equals 90 when spending, two kinds of microcell degeneracys become a kind of microcell (that is, all liquid crystal are arranged along a direction), and its arrangement is vertical with the incident light polarization direction.For non-vanishing any+θ or-the θ angle, when observing with single polarizer, the angle position of dyestuff absorption peak changes with respect to background.In addition, when observing, the color of exposure region changes with respect to background with two polarizers (each one on the both sides of box), and variation has taken place in this angle position that shows liquid crystal molecule.
In this example, using power is that 1.2 watts, wavelength are the laser instrument of 514.5 nanometers, and its time shutter is 45 minutes, and observed+θ is about 45 degree with the size of-θ.
Example 2
This example shows, if polarized light is within the absorption band of liquid-crystal compounds, then can liquid crystal (no dyestuff) reorientation be arranged with method of the present invention.
Liquid crystal is a ZLI4139(EM Industries company, Hawthorne, New York), it is that a kind of ferroelectric liquid crystals (demonstrates room temperature chiral smectic C phase.ZLI4139 has strong absorption band in the ultraviolet region, do not add dyestuff in the liquid crystal.Make box as example 1, but use the Pyrex slide of no ITO coating (can obtain from VWR Scientific company, San Francisco, California) to guarantee low absorption in the ultraviolet region, fiber with 5 microns provides spacing, box is full of with capillary action at 130 ℃.
Adopt the device (without lens) of Fig. 2 that ready-made liquid crystal cell is exposed.Light source be polarization helium cadmium laser (derive from Liconix company, Sunnyvale, California), its emission wavelength is 325 nanometers.Beam diameter is about 1 millimeter, and laser power is about 1.0 milliwatts.With box exposure 1 minute and check it.The angle position of the liquid crystal molecule of exposure area is different with the position of background.Because the absorption of laser is very remarkable, molecular changes on the incident of box one side with respect to the orientation of incident light polarization direction, but the light of box penetrates the molecule uninfluenced (that is, light is absorbed, and fails to penetrate liquid crystal media so that the molecule exposure at box rear portion) on the one side.The result has formed the liquid crystal aligning that reverses and has arranged in element.
Example 3
The explanation of this example with the polarized light of wavelength within the liquid crystal absorption band, is arranged host and guest's system reorientation according to the present invention.
Make box and it is full of as example 2, difference is to use the dyestuff 2 that is dissolved in the main body liquid crystal, and its concentration is 0.6% of liquid crystal weight.
Use device (without lens) as shown in Figure 2 that ready-made liquid crystal cell is exposed.Light source is the helium cadmium laser of the polarization described in the example 2.The box exposure was checked it after 15 minutes.The dichromatism of irradiation area is different with the background dichromatism.Rotation angle with respect to the incident light polarization direction is about 30 degree.Because the absorption of polarized light is very remarkable, the molecular changes on the light incident of the box one side to the orientation of incident light polarization direction, but the molecule on the light-emitting face of box is uninfluenced.The twist alignment that has formed liquid crystal and dye molecule in box is arranged.
Example 4
This example explanation host and guest system can be arranged with the white light reorientation of polarization.
Make liquid crystal cell and it is full of as example 3.(Olympus Optical Co., Ltd, Tokyo is Japan) with ready-made box exposure with an Olympus BH-2 type polarizing microscope.Microscope uses xenon lamp to generate white light, then white light is passed through polarizer.Box at room temperature exposes the reorientation arrangement did not take place in 2 hours.But, by using a Mettler FP52 heat platform and FP5 temperature controller (Mettler instrument company, Princeton, New Jersey), box rises to 10 ℃ from room temperature (25 ℃) per minute, rises to 100 ℃ (the isotropic transition temperature of ZLI4139 is 82 ℃).With the white light of polarization along the initial arrangement direction irradiation capsule of liquid crystal when the room temperature.Between exposure period, the temperature of box is reduced to room temperature with 1 °/minute speed from 100 ℃.The orientations of finding exposure region becomes approximately with the incident light polarization direction+30 and-30 degree angles.
Example 5
Make box and it is full of as example 1, difference is that the concentration of used dyestuff 1 is 7.0% of liquid crystal weight.Carrying out reorientation as example 1 arranges.After exposure 20 minutes, with respect to the incident light polarization direction+θ is 90 degree with-θ angle.When the time shutter was increased to more than 20 minutes, the size of+θ and-θ did not increase to such an extent that surpass 90 degree.
Example 6
Repeat example 1 with a kind of different azo dyes that is dissolved in the nematic liquid crystal main body.
Make liquid crystal cell and it is full of as example 1, difference is to use the dyestuff 3 that is dissolved in the main body nematic liquid crystal, and its concentration is 1.25% of liquid crystal weight.
Carrying out reorientation as example 1 arranges.Exposure after 45 minutes with respect to the incident light polarization direction+θ is 90 degree with the size of-θ.
Example 7
Repeat example 1 with the anthraquinone dye that is dissolved in the nematic liquid crystal main body.
Make box and it is full of as example 1, difference is to use the dyestuff 4 that is dissolved in the nematic liquid crystal main body.Its concentration is 1.5% of liquid crystal weight.
Carrying out reorientation as example 1 arranges.Exposure after 45 minutes with respect to the incident light polarization direction+θ is about 45 degree with-θ angle.
Example 8
Repeat example 1, but without polyimide alignment layers.
Make liquid crystal cell and it is full of as example 1, difference is not have coating polyimide layer (so the surface is not rubbed) on the glass substrate of ITO coating, simultaneously with the fiber of 11 microns of 10 microns fiber replacements.In addition, replace dyestuff 1 with the dyestuff 5 that is dissolved in the main body, its concentration is 0.28% of liquid crystal weight.
Laser same in use and the example 1 carries out orientations.After exposure 80 minutes, with respect to the incident light polarization direction+θ is about 30 degree with the size of-θ.The homogeneity of orientation meets the requirements in the exposure area, but good not as having the situation of the polyimide alignment layers that rubbed.
Example 9
This example shows host and guest's liquid crystal system reorientation arrangement of arranging with method of the present invention reorientation.
Make box and it is full of as example 1, just working concentration is the dyestuff 1 of liquid crystal weight 2.0%.Carry out the reorientation arrangement first time as example 1.Expose after 5 minutes, with respect to the incident light polarization direction+θ is about 90 degree with-θ angle.Subsequently, box is rotated 30 degree (in the plane perpendicular to the incident laser light beam), and the same position exposure that has exposed for the first time 5 minutes.Observe dyestuff and liquid crystal molecule and rotate+90 and-90 degree with respect to the incident light polarization direction, the direction that this about and previous reorientation is arranged becomes 30 to spend angles.
Example 10
The orientations of this example expression host and guest liquid crystal media wherein has a kind of dyestuff to be incorporated in the polyimide alignment layers of box.
Make liquid crystal cell as example 1, difference is, is containing 0.5%(weight) in 1-Methyl-2-Pyrrolidone (NMP) solution of polyimide, add the dyestuff 5 that accounts for NMP weight 1%.With this potpourri spinning on the substrate that has applied ITC, as example 1 with its curing.
Before host and guest's potpourri of mentioning in liquid crystal cell is saved by the making one at box is full of, by system shown in Figure 2 (without lens) box is exposed with the laser described in the example 1.The incident light polarization direction is parallel to the straight line frictional direction of box.After with power being 1.2 watts, the laser explosure of wavelength 514.5 nanometers 15 seconds, box is full of with host and guest's potpourri by example 1 described step, difference is, adopting concentration is that 0.28% dyestuff 5(structure of liquid crystal weight sees Table 1) be dissolved in the main body nematic liquid crystal.The exposure area demonstrates relative to the incident laser polarization direction has one+90 and-90 degree to rotate.The exposure area of box is along the frictional direction orientations.Because dyestuff is positioned in the polyimide alignment layers, take place than viewed remarkable shortening in each example of front the required time shutter of induced with laser orientations.
Example 11
The expression of this example is mixed in the polyimide alignment layers of liquid crystal cell under the situation of dyestuff, utilizes the present invention with the liquid crystal media orientations.Make box and make its orientations as example 10, just do not sneak into dyestuff in the liquid crystal.The exposure area demonstrate relative to the incident light polarization direction have+90 or-90 the degree rotate.Liquid crystal molecule in the box unexposed area is along the frictional direction orientations.
Example 12
The expression of this example is mixed under the situation of dyestuff the orientations of host and guest's system in the polyimide alignment layers without friction of box.
Make liquid crystal cell and make its orientations as example 10, just polyimide/dyestuff the oriented layer of solidifying is without friction.The exposure area demonstrates with the incident light polarization direction+90 or-90 rotations of spending, and the box of its homogeneity orientations in example 10 and 11 is good.Flow direction orientations when the unexposed area edge of box charges into.
Example 13
This example is illustrated in the orientations of liquid crystal under the situation of mixing dyestuff in the polyimide alignment layers of box without friction.
Make box and make its orientations as example 12, just in nematic liquid crystal, do not dissolve in dyestuff.The result is the same with example 12.
Example 14
With the reorientation arrangement of the box of method orientations of the present invention, wherein oriented layer is made of polyimide and dye mixture in advance for this example expression.
Make liquid crystal cell and make its orientations as example 10, difference is, the polyimide of curing/dyestuff oriented layer is without friction, and uses light beam through the lens expansion with box exposure 5 minutes.Before filling box with host and guest's potpourri, (a) light beam is covered retaining, make that the size of light beam is little than beam area used in the initial exposure, (b) box is rotated about 45 degree and in perpendicular to the plane of incident beam (c) subsequently with box exposure 5 minutes within the exposed areas formerly.Fill box by example 1 described step with host and guest's potpourri then.Initial exposure zone (only exposure once zone) demonstrates with the incident light polarization direction of exposure for the first time to become+rotations of 90 and-90 degree, and exposure area (expose twice zone) then spends with-90 with respect to the incident light polarization direction rotation+90 of exposure for the second time again.The box of the orientations of overlapping region in example 10 and 11 is good.The unexposed area of box is along the flow direction orientations of dress during box.
Example 15
The laser light orientation of this example expression host and guest system is arranged, and wherein dyestuff directly places on the transparent conducting coating of glass substrate part.
Make box as example 1, be polyimide spinning of no use on the ITO of each substrate layer, but replace the dyestuff 4 that accounts for NMP weight 1%, be added to it among the NMP and spinning on the ITO layer.Place and made NMP evaporate in 1 hour.The result stays the film of one deck dye molecule on the ITO of substrate layer.Use the polishing cloth friction surface, the fiber with 10 microns when making box provides at interval.
Host and guest's liquid crystal compound of mentioning in making one joint with liquid crystal cell exposes with the laser described in the example 1 box before being full of box by system shown in Figure 2 (without lens).The incident light polarization direction is vertical with the linear friction direction of box.After the laser explosure of using 1.2 watts of power, wavelength 514.5 nanometers 10 seconds, fill box by example 1 described step with guest-host liquid crystal material, when charging into box, observe lip-deep dyestuff and be added in host and guest's material.The exposure area demonstrates with the incident light polarization direction+90 and-90 rotations of spending.The unexposed area of box is along the frictional direction orientations.
Example 16
This example shows that the ferroelectric liquid crystals main body with chiral smectic C room temperature phase can be arranged with method reorientation of the present invention.
The main body liquid crystal is a BDH SCE-4(BDH company, Poole, Britain), it is a kind of ferroelectric liquid crystals.Be dissolved with the dyestuff 2 that accounts for liquid crystal weight 2.0% in the ferroelectric liquid crystals main body.Make box and it is full of as example 1.
With the device of example 1 described laser ready-made box is exposed by Fig. 2.Use lens that beam diameter is extended to 1 centimetre.Laser with 1.0 watts of power, wavelength 514.5 nanometers exposes box 25 minutes.Because the transverse energy density unevenness of 1 centimetre of laser beam is even, so have nothing in common with each other along the angle of rotation of position that laterally respectively expose with respect to the incident light polarization direction.But polarized light makes the exposure position orientations must be different with the unexposed area really.
Example 17
This example shows that the liquid crystal main body with stratose A room temperature phase can be arranged with method reorientation of the present invention.
The main body liquid crystal is to show that in room temperature the BDH S23C(of stratose A phase is available from BDH company, Poole, Britain).Be dissolved with the dyestuff 6 that accounts for liquid crystal weight 1.0% in the liquid crystal main body.Make box as example 1.Box is filled at 130 ℃ by capillary action, sealed with epoxy resin.
Finish orientations as example 1.Low-light with 0.9 watt of power, wavelength 514.5 nanometers exposes element 45 minutes.Polarized light is arranged in the exposed portion reorientation with the incident laser polarization direction and is approximated to+90 and-90 degree.
Example 18
This example shows with method of the present invention arranges liquid crystal aligning, and one of them substrate scribbles polyimide alignment layers, contains the anisotropic absorption dyestuff in this layer.
Make liquid crystal cell as example 10, difference is, with polyimide/dyestuff 5/NMP potpourri spinning on the ITO of substrate layer, simultaneously with polyimide/NMP potpourri spinning on the ITO of another substrate layer.Two substrates all equally are cured by example 1.With linear fashion two substrates that rub, make box with polishing cloth, just use 10 microns fiber control interval instead as example 1.
, liquid crystal cell is exposed in example 1 as polarized light source with argon laser.The incident light along the frictional direction linear polarization with 0.8 watt exposes box 5 minutes.With two polarizers, observe the exposure area and have twist alignment and arrange (that is, becoming with liquid crystal molecular orientation on polyimide base film 90 to spend) in the orientation of the on-chip liquid crystal molecule of polyimide/dyestuff.
Claims (13)
1, the method for arranging of the molecular orientation in a kind of liquid crystal media of the surface being pressed close to substrate, it is characterized in that, the molecular weight of liquid crystal is less than 1500 in this medium, anisotropic absorption molecule in the medium or in the substrate of pressing close to it is exposed with linearly polarized photon, light wavelength is within the absorption band of anisotropic absorption molecule, by the anisotropic absorption molecule of exposure, bring out the liquid crystal media orientations become to become with the incident beam linear polarization direction+θ or-the θ angle.
2, according to the method for claim 1, its feature is that also the anisotropic absorption molecule is thermotropic liquid crystal compound or dichroic dye, their dichromatism absorption band in about 150 nanometers between 2000 nanometers.
3, according to the method for claim 1 or 2, its feature also is, contains anisotropic absorption molecule in the liquid crystal media.
4, according to the method for claim 1 or 2, its feature is that also substrate contains anisotropic absorption molecule.
5, according to the method for claim 3, its feature is that also the anisotropic absorption molecule is thermotropic liquid crystal compound or dichroic dye.
6, according to the method for claim 4, its feature is that also the anisotropic absorption molecule is nematic phase or smectic liquid crystal compound.
7, according to the method for claim 4, its feature is that also the anisotropic absorption molecule is the dichroic dye that is dissolved in the thermotropic liquid crystal compound.
8, according to the method for claim 1, its feature is that also before the anisotropic absorption molecule was to the polarized light exposure, liquid crystal media was parallel to substrate orientation and arranges.
9, according to the method for claim 1, its feature is that also linearly polarized photon is sent by argon, helium, neon or helium cadmium laser.
10, according to the method for claim 2, its feature also is, the anisotropic absorption molecule is a dichroic dye, be selected from azo, diazonium, nitrine, bisdiazo, five nitrogen, anthraquinone, colour developing cyanine, methine, 2-phenylazo thiazole, 2-phenylazo benzothiazole, 4,4 '-two (fragrant azo group) Qi, perylenes and 4, the 8-diaminostilbene, the 5-naphthoquinone dyestuff.
11, according to the method for claim 1, its feature is that also this method is carried out in the presence of electric field.
12, root is drawn together the method for claim 1, and its feature is that also substrate comprises an oriented layer that rubbed.
13, according to the method for claim 12, its feature is that also the anisotropic absorption molecule constitutes the part of oriented layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 90107239 CN1026364C (en) | 1990-09-03 | 1990-09-03 | Process of aligning liquid crystal media |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 90107239 CN1026364C (en) | 1990-09-03 | 1990-09-03 | Process of aligning liquid crystal media |
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| Publication Number | Publication Date |
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| CN1059604A CN1059604A (en) | 1992-03-18 |
| CN1026364C true CN1026364C (en) | 1994-10-26 |
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| CN 90107239 Expired - Lifetime CN1026364C (en) | 1990-09-03 | 1990-09-03 | Process of aligning liquid crystal media |
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| CN101846811A (en) * | 2005-03-01 | 2010-09-29 | 荷兰聚合物研究所 | Polarization grating in the mesogenic films |
| JP6718657B2 (en) | 2015-02-27 | 2020-07-08 | 住友化学株式会社 | Composition |
| CN111641046B (en) * | 2020-05-07 | 2021-07-06 | 宁波大学 | Microwave band broadband circular dichroism chirality wave absorber |
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