DE2200424A1 - Imaging system - Google Patents

Description

Patent attorneys Dipl.-Ing. E We ic km an ν,

Dipl.-Ing. H.Weickmann, Dipl.-Phys. Dr.K. Fincke Dipl.-Ing. V. A. Weicrmann, Dipl.-Chem. B. Huber

2200424 ⁸ MUNICH 86, DEN

POST BOX S60 820 MOHLSTRASSE 22, CALL NUMBER 48 39 21/22

Kn

CASE? Z 772 (XD / 2573) -CIC

XEROX CORPORATIOIi, Xerox Square, Rochester, H "Y _e 14603, V.St.A"

"Imaging system"

The invention relates to an imaging system, in particular an imaging system in which the imaging member comprises an imaging swat er ial with C3iolesterischen _s liquid-crystalline properties. In addition, the invention relates in particular to a new system for thermal imaging of such a liquid-crystalline imaging member »

More recently, there is a substantial interest in the development brauchbarerer applications for the "liquid crystals" as a known substance Klaase _o The Uame "liquid crystals" for liquid-crystalline materials / orden usual gov showing dualistic physical properties, some of which in typical Wisely suck liquids

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and others that are typical for solids alone. Liquid crystals show mechanical properties, such as viscosities, which usually belong to liquids. The optical scattering and permeability properties of liquid crystals correspond to properties usually found only in solids. In liquids or fluids, the molecules are normally randomly distributed and oriented throughout the substance; conversely, in crystalline solids, the molecules are generally rigidly oriented and arranged in a specific crystalline structure. Liquid crystals are similar to solid crystals in that the molecules of the liquid crystalline substances are regularly oriented, in a manner analogous to> but less comprehensive than the molecular orientation and structure in an icrystalline solid. It has been found that many substances exhibit liquid-crystalline properties in a relatively narrow temperature range, the substances appearing as crystalline solids below such temperature ranges and typically appearing as liquids above such temperature ranges. It is known that liquid crystals come in three different mesomorphic forms: the smectic, nematic and cholesteric forms. In each of these structures, the molecules are typically arranged in a specific, single orientation.

It was found that liquid crystals against a variety of stimuli, including temperature, pressure, other chemical compounds, and electric and magnetic fields are sensitive or responsive to it, for example, in British Pat. No. 1,235,552, French Patent 1,484,584 US patent specifications 3,409,404 and 3,439,525 and described in the filed on January 21, 1970 USF application Ser. No. 4,644th

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In particular, there are different temperature effects for liquids Crystals have been described "see the TJ.S" patents 3 IH 836, 3 410 999, 3 415 991 and 3 441 513.

In all recently Abbxldungssysteme have been discovered and described in which the imaging member comprises a liquid crystalline material comprises "cf." z _e B, German Patent Applications P 20 40 120.1 and P 20 51 505.3 sov / ie filed on 5.KaI 1969 ' possibly patent application no. 821 565. It is known that cholesteric liquid crystals have different perceptible textures. For example, can cholesteric ^ _? liquid crystals assume a homeotropic, a focal-conical or a "Grandjean" flat texture, as modifications of the cholesteric mesophase itself, as stated by Gray GW, in Molecular Structure and the Properties of Liquid Crystals, Academic Press, Loadon, 1962 ₉ pages 39-54. An imaging system that makes use of these different textures is described in German patent application P 20 51 505.3 «,

In BGUcn and growing areas of technologies such as the area of liquid crystalline imaging systems, methods, devices ₉ compositions and

_lü ..-! ",. s eproducts for the novel application of the new! ■ echnv · developed" The present invention relates to a latest ^ rtexlhaftes system for mapping on cholesteric, liquid-crystalline parts "

The object of the present invention is therefore to create a new imaging system, a new plu-crystal imaging system, that generates high resolution images from thermal stimulation, the imaging or presentation system has an image storage capacity that, Ιλ.Ι or the demonstration is erasable and the image parts ■ -'.-: ■■ ".erv" ~ -are applicable. The object of the invention is also

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the creation of a mapping system that is neither a development. Winding stage still, a pre-treatment stage, such as electrical Charging, or chemical activation, is required and suitable for use in demonstration facilities that can be addressed thermally or in any other suitable manner; Finally, the invention is also intended to be a color demonstration s ~ and color imaging system can be created.

According to the invention, these tasks are achieved with a system by an imaging member that is a material with a cholesteric, liquid-crystalline phase in its state "Grandjean" or "disturbed" texture includes being thermally imaged by having image portions of that imaging material are heated imagewise to a temperature above the temperature range for the cholesteric, liquid-crystalline, mescmorphic state of the material and the heated parts of the imaging material to a temperature in the temperature range of the cholesteric, liquid-crystalline The mesophase of the material can return, whereby the depicted areas the state of the focal-conical or "undisturbed" Accept the texture in the desired image configuration. The images according to the invention are erasable and the image parts are reusable.

For a better understanding of the invention, some preferred embodiments are to be taken in conjunction with the accompanying drawings described:

Fig. 1 illustrates, in partial schematic cross-section, an imaging part suitable for use is useful in the present invention.

Fig. 2 illustrates in a partial schematic cross-section an imaging part that is produced with the aid of a imaging method according to the invention is provided with an image.

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Pig. 3 illustrates in a partial schematic Cross-section of an imaging part, which with the aid of an imaging method according to the invention with an image has been provided.

FIG. 4 is a front view of the illustrated portion of the Mg. 3.

Figure 1 illustrates an imaging member 10 that is suitable for use is suitable in the advantageous system of the invention, the substrate 11 carries a layer 12 of imaging material, which comprises a material which has a cholesteric, liquid crystalline mesophase.

The carrier substrate 11 can include any suitable material, in various embodiments, the substrate may take any suitable shape, including Form of a fabric, a film, a laminate or the like, a strip, film, a rail, a cylinder, a drum, an endless belt, an endless Moebius strip, a circular disc or other geometric shapes. The substrate material can be transparent, translucent or be opaque. In particularly preferred embodiments of the imaging part of the present invention the substrate is preferably a material that has low thermal conductivity. Of course, the substrate material should be compatible with the material including the layer of imaging material 12.

The layer of imaging material 12 can be any suitable Contain material that exhibits the cholesteric, liquid-crystalline mesophase.

Any suitable cholesteric liquid crystal, mixture or composition containing liquid crystals

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or composition with cholesteric, liquid-crystalline Properties can be used here. The cholesteric, suitable for use in the present invention liquid crystals include derivatives from conversions of cholesterol and inorganic acids, ζ · Β. Cholesteryl chloride, Cholesteryl bromide, cholesteryl iodide, cholesteryl fluoride, Cholesteryl nitrate; Esters derived from reactions of cholesterol and carboxylic acids, e.g., cholesteryl crotonate; Cholesteryl nonanoate, cholesteryl hexanoate, cholesteryl formate, Cholesteryl docosonoate; Cholesteryl chloroformate; Cholesteryl propionate; Cholesteryl acetate; Cholesteryl valerate; Cholesterol vacconate; Cholesteryllinoleatj Cholesteryllinolenatj Cholesteryl oleate; Cholesteryl lucate; Cholesteryl butyrate; Cholesteryl caprate; Cholesteryl laurate; Cholesteryl myristate; Cholesteryl clupanodonate; Ethers of cholesterol, such as cholesteryl decyl ether; Cholesteryl lauryl ethers; Cholesteryl oleyl ether; cholesteryl dodecyl ether; Carbamates and carbonates of cholesterol such as cholesteryl decyl carbonate; Cholesteryl oleyl carbonate; Cholesteryl methyl carbonate; Cholesteryl ethyl carbonate; Cholesteryl butyl carbonate; Cholesteryl docosonyl carbonate; Cholesteryl cetyl carbonate; Cholesteryl p-nonylphenyl carbonate; Cholesteryl 2- (2-ethoxyethoxy) ethyl carbonate; Cholesteryl 2- (2-butoxyethoxy) ethyl carbonate; Cholesteryl 2- (2-methoxyethoxy) ethyl carbonate; Derived from cholesteryl heptyl carbamate and alkyl amides and aliphatic secondary amines of 3-ß-amino- ^ 5-chols and mixtures thereof; Peptides like Polybenzyl glutainate; Derivatives of ß-sitosterol, such as sitosteryl chloride and active amyl esters of cyanobenzylidene aminocinnamate. The alkyl groups in these compounds are typically saturated or unsaturated fatty acids or alcohols having fewer than about 25 carbon atoms and unsaturated chains of fewer than about 5 double-bonded olefinic groups. Aryl groups in the above compounds include monosubstituted benzene ring compounds. Every of the above compounds and mixtures thereof, suitable cholesteric, liquid-crystalline materials can advantageously

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adhere to the system of the present invention.

Smectic liquid crystalline materials are suitable for use as components of the imaging composition in the present invention, such smectic liquid crystalline materials include: n-propyl-4 ¹ -ethoxybiphenyl-4-carboxylate; 5-chloro-6-n ~ heptyloxy-2-naphthoic acid, low-temperature mesophases of cholesteryl octanoate, cholesteryl nonanoate and other open-chain aliphatic esters of cholesterol with chain lengths of 7 or more; Gholesteryl oleate; Sitosteryl oleate; Cholesteryl decanoate; Cholesteryl laurate; Cholesteryl myristate; Cholesteryl palmitate; Cholesteryl stearate; 4 ^f -n-alkoxy-3'-nitrobiphenyl-4-carboxylic acids; ethyl-p-azoxy-cinnamate? Ethyl p-4-ethoxybenzylidene «aminocinnamate; Ethyl ~ p-azoxy-benzoate; Potassium oleate; Ammonium oleate; pn-octyloxy-benzoic acid; the low-temperature mesophase of 2-p ~ n-alkoxy-benzylidene-aminofluorenones with chain lengths of 7 or more; the low temperature mesophase of p- (n ~ heptyl) -oxybenzoic acid; sodium stearate anhydrous; Thallium (l) stearate °, mixtures thereof and others.

The nematic liquid crystalline materials suitable for use as components of the imaging composition in the advantageous system of the present invention include p-azoxyanisole, p-azoxyphenetol, p-butoxybenzoic acid, p-methoxycinnamic acid, butyl-p-anisylidene-paminocinnamate , Anisylidene-p-aminophenyl acetate, p-ethoxybenzalamino-a-methylcinnamic acid, 1,4-bis (p-ethoxybenzylidene) cyclohexanone, 4,4'-dihexyloxybenzene, 4,4'-diheptyloxybenzene, anisal-p-amino -azobenzene, anisaldazine, a-BenzoJü-zoCanisal-a ¹ -naphthylamine), η, η'-lionoxybenztoluidine; Aniles of the general group (pn-alkpxybenzylidene-pn-alkylanilines) such as methoxybeneylidene-butylaniline, mixtures of the above and many others.

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The above compilations of materials that different have liquid-crystalline phases, do not represent an exhaustive or restrictive list «The compilations disclose a variety of representative materials suitable for use in the imaging composition or mixture, the cholesteric ^, liquid-crystalline materials contains, are suitable and which the active, imaging element in the advantageous system of the present Invention included.

The liquid crystalline materials can be prepared v / ground by the liquid crystals, or mixtures thereof in a suitable solvent, Z ₀ as organic solvents such as chloroform, trichlorethylene, tetrachlorethylene, Petfoläther, methyl ethyl ketone and other triggers. The solution containing the liquid crystal material is then typically cast, sprayed, or otherwise applied onto a suitable substrate. After the solvent has evaporated, a thin layer of liquid crystals remains. Alternatively, the individual liquid crystal materials of the liquid-crystalline mixture can be combined and applied directly by heating the mixed components above the isotropic transition temperature and mixing the components prior to application to a suitable substrate.

The liquid crystal imaging layers suitable for use in the present invention preferably have a thickness in the range of about 250 / U or less; even thicker films behave satisfactorily in the system according to the invention. Optimal results will usually be achieved when using layers in the thickness range between about 1 / u and about 50 / u. Becomes a layer of the imaging composition .1.2 produced on a suitable substrate 11 by methods as described above, so the material that makes the cholesteric ^, liquid-crystal-

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line contains meso phase, often the state of its "Grandjean" or "disturbed" texture. In some cases, however, the material can be made to assume the state of its "Grandjean" texture by mechanical perturbation, such as vision or pressure, or by external forces, such as electric or magnetic fields, or by other suitable means. The "Grandjean" texture is usually characterized by selective reflection of incident light around a wavelength \ ~ , where A ₀ = 2np and η is the refractive index of the composition of the layer and ρ is the helical pitch of the liquid crystalline film and it is additionally characterized by optical activity for wavelengths of incident light apart from A _Q. If Aq ^{lies in the} visible spectrum, the composite layer, which contains the cholesteric, liquid-crystalline material, appears to have the color corresponding to Aq when light is incident perpendicularly and viewed perpendicularly, and if \ _Q lies outside the visible spectrum, the composite appears The layer is typically colorless and non-scattering. The "Grandjean" texture of the cholesteric liquid crystals is sometimes referred to as the "disturbed" texture.

An imaging member 10 which has been manufactured so that the imaging layer, the material in the cholesteric, contains liquid-crystalline mesophase, is in the state of its "Grandjean" or "disturbed" texture, is advantageous System of the present invention through the imagewise application of thermal energy, or energy used to generate an imagewise thermal effect in the layer of imaging material is capable of being imaged. An embodiment of the advantageous system of For example, the present invention is illustrated in Figure 2 where the imaging material layer 12 is shown through a stencil-like mask 13 of the imagewise exposure

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mm I {J m »

thermal radiation 14 emitted from a source 15 under the screen 16. Any source of thermal energy Energy such as lasers, gas discharge larapes, and others can be used as an energy source in the imagewise exposure stage be used. Furthermore, in addition to that described above System of imagewise exposure through a mask or stencil any suitable aid for a imagewise exposure can be used. Even light pens or thermal pens are different for use Embodiments suitable.

In the system according to the invention, the thermal energy, which is in an image-like configuration on the layer of the imaging Composition is applied, applied in such a large amount that the imaging material, the material with the contains cholesteric, liquid-crystalline mesophase, in the imagewise irradiated areas at a temperature of at least about the liquid-crystalline, liquid-isotropic transition temperature of the imaging material which has the characteristics of the cholesteric, liquid-crystalline mesophase ", is heated. After the imagewise application of so much thermal energy that the temperature of the imaging material in the imagewise irradiated areas to a temperature of at least about the isotropic transition temperature has been raised, the thermal energy source is removed and the imaging composition is left cool to a temperature which is in the temperature range of the cholesteric, liquid-crystalline mesophase and is below the isotropic transition temperature of the composition.

Although in many embodiments the temperature is typically at or above the liquid-isotropic transition temperature is raised, it is found that in some embodiments temperatures within a few degrees Celsius of the liquid isctropic Transition temperature of the imaging composition, i.

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at least approximately the liquid-isotropic transition temperature _{p is} sufficient to achieve the desired effect in the desired image areas. For example, it has been found that temperatures sufficient within about 5 ⁰ C to the isotropic transition temperature, in order to achieve the desired effect in some Ausführimgeforinen.

Wake up cooling down in the temperature range of cholesteric ^; Liquid-crystalline mesophase show the imagewise irradiated areas of the imaging composition in a typical manner the state of the focal-conical or "undisturbed" texture and thereby create an imaged part, the image surfaces of the imaging composition that a material possesses contains, which has the cholesterol "liquid-crystalline mesophase in the state of the focal-conical texture and Background areas of the imaging composition have material with a cholesteric, liquid-crystalline Mesophase in the state of the "Grandjean" texture type includes «

The focal-conical texture type is also typically characterized by selective reflection5, but this texture state also shows diffuse scattering in the visible spectrum, whether Λ ^ is in the visible spectrum or not. The appearance of the focal-conical texture state is typically milk-white when \ _{0 is} outside the visible spectrum "The focal-conical texture of cholesteric, liquid-crystalline materials is often referred to as the" undisturbed "texture state",

In numerous embodiments of the illustration part of the present. In the invention, it may be advantageous to use substrate materials that are translucent to visible light or are substantially transparent. In such embodiments, the imaging member can be used as a Be suitable for transparency. If the imaging material, which is a material with a cholesteric, liquid-crystal-

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linen mesophase, first made on the substrate the composition will normally appear colored or - if transparent - colorless. When such a transparency is viewed between polarizers, it appears it usually colored or black after imaging by the advantageous system of the present invention, however are the image areas of the material created by the thermally induced texture transition mapping system of the present invention Invention have been treated, normally considerable, since the imaging layer becomes white in the imaged areas that diffusely scatter the polarized light, which can then at least partially be transmitted through the polarizer to the viewer's eyes. To this The imaging system creates a white or light image on a dark or colored background, if such a background Is viewed transparently between polarizers.

The effect of the thermally induced texture change in the imaged areas lies in the destruction of the polarization of transmitted light in the image areas, whereas the background areas have little effect on the polarization, except in a narrow wavelength range. This narrow area, here called raitAA, is _{centered around ^ 0} = 2np, where η denotes the refractive index of the composite layer and ρ denotes the helical pitch of the cholesteric, liquid-crystalline material. Typically the ratio is

-Δ-0 = about H. ΔΛ

In this area, incident plane-polarized light occurs from the imaging layer, which contains material with the cholesteric, liquid-crystalline mesophase, as circularly polarized Light off. Between crossed polarizers the imaged areas therefore appear white or light

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black or colored background. Becomes an imaging part including a support substrate between crossed polarizers considered, the substrate material should be optically isotropic, i.e. it should reflect the polarization of the Do not change the system of gone light,

FIG. 3 shows, in a partial schematic cross section, an illustrated part, in which the layer of the imaging composition 12 has imaged areas 17 in the state of the focal-conical or "undisturbed" cholesteric, liquid-crystalline texture, while the background areas have the state of the "Grandjean" or have "disturbed" cholesteric, liquid-crystalline texture. The thermally induced texture transition mapping effect of the present invention is typically a bulk effect. The "bulk effect" is shown in FIG. 3, v / o imaged areas YJ of the layer of imaging composition 12 are shown schematically as converted through the entire cross-section of the composition,

Figure 4 is a front view of the imaging portion of Figure 3 (The view of FIG. 3 being a cross-section along the line 19), which schematically shows image areas 17 in the focal-conical texture state on background areas 18 in the "G-randjean" texture condition «Although the image areas 17 in Fig. 4 are shown here as the darker areas, the contrast and density of one by the advantageous The imaged portion produced by the system of the present invention may vary from one embodiment to another. Fig. 4 should be a representation of a part provided with an image, in which the imaged areas 17 are clearly visually distinguishable of the background areas are 18.

In addition to the methods of viewing already described above of images made with the system according to the invention

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any other suitable means of viewing such images, e.g. or reflected light or even with projection equipment, be suitable for use in connection with the present invention. Appear in penetrated light illustrated 'files (which typically have an essentially transparent carrier substrate) milky or white, in the imaged areas with converted texture, while the unconverted background areas of the imaging composition layer will typically remain more translucent or translucent. With The transmitted light method of viewing such images is particularly suitable for use in image projection systems which normally enlarge the image produced by the system of the invention. When viewed in reflected light, the imaged part has clearly distinguishable image and background areas which may be of various colors or colored image areas on a substantially colorless background to have. In a specific method, for example, an infrared reflective (i.e. transparent) layer of imaging, Composition placed on a mirror substrate and imaged around the image-like converted areas into the visible, focal-conical texture, whereby colored image areas are created on an im essentially transparent background through which incident light is reflected from the mirror substrate.

In addition to the imaging aspects of the system according to the invention it should be noted that on the imaging parts of the present invention, the images - such as those by the inventive System generated - can be deleted, e.g. through the application of external forces such as pressure, shear stress, electric fields, magnetic fields, or combinations thereof. These erasure methods are essentially the same methods discussed here earlier as methods

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have been, with which the mapping composition to ge = can be brought to their "Grandjean" - or "disturbed" texture state to accept. After such an illustrated part has erased the image, the part is usually for one Recovery of an image useful with the inventive system. In this way, imaging parts of the present invention reusable for a large number of imaging and erasing cycles The erasability of the The innovative system also promotes the usability of this one-step, instantly visualized image systero.

In many embodiments of imaging parts suitable for use in the inventive system, it may be highly desirable that the layer of imaging composition be covered or encased in a thin, transparent covering material. For example, a layer of cholesteric imaging composition may have a suitable substrate covered with a thin, transparent poly of Mylar polyester resin film, available from BuPont _s transparent polyethylene, polyvinyl chloride or Tedlar, a polyvinyl fluoride resin film from DuPont, or thin glass covers covering film are included »

Such cover or containment films are generally no more than about 0.254 mm (10 mils) thick, with thinner films being preferred. The films are transparent, preferably not infrared absorbing, preferably not of high heat capacity and otherwise with the other elements compatible with the imaging system.

Although the innovative system above in conjunction with that Drawings Fig. 1 to Fig. 4 has been described in general, any suitable aid or material that can be used for education

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Development of the desired result of the inventive system can be used in the various process stages of the inventive system. The device for transferring thermal energy in an image-like configuration to the imaging part can be any suitable device. As shown in Fig. 2, for example, a suitable heater 15 are used to send thermal energy H through a suitable mask member 13. Any suitable source of thermal energy can also be used, which source itself has an imagewise configuration. For example, a heated pen or other heated member itself in the desired imagewise configuration can be brought in close proximity to the imaging layer to achieve the beneficial results of the inventive system. A particularly preferred method of thermal imaging within the scope of the inventive system relates briefly to flashing with a high-energy xenon flash lamp over an imaging part which is optically masked in the desired image configuration. Other sources of the desired thermal energy can include modulated lasers or light pens. In yet other systems where the imaging material is used in conjunction with electrically conductive substrates or masks, HP microwave energy inputs can be used to imagewise subject the material to thermal energy in order to achieve the inventive effects.

The image-like irradiated areas of the imaging material are subjected to the action of energy inputs which are im typically all in the range between about 1 and 100 millijoules / cm imaging surface, depending on the thickness of the imaging composition and the proximity of the imaging transition temperature the starting temperature of the imaging part. Again, it should be noted that the inventive imaging system unites Volume effect ("bulk effect") generated in the layer of the imaging material. It was found that the short-term, high-intensity

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j actual-lightning-t-mapping method of the present invention : because of their speed, which limits the time in which ι lateral thermal conduction can take place, and thereby the Increasing resolution in the inventive imaging system is particularly advantageous. Of course, making a wise choice helps of the imaging materials and substrates in the inhibition of the lateral thermal conduction and thereby promotes 'corresponding to the resolution in the inventive system.

A clear understanding of the new texture transition mapping system of the present invention will make it clear that the temperature conditions under which the system must be used may make some mapping material appear preferable for use under certain conditions. For example, when the present imaging system is used at 'room temperature, so are imaging materials, j the cholesteric ^, liquid-crystalline properties at or ■ near room temperature (ie, in the range between about 2O ⁰ C and about 30 G) which is preferred. In addition, it is usually preferred to use imaging materials whose cholesteric, liquid-crystalline mesophase / liquid-isotropic transition temperature is well above the ambient conditions under which the system must be used; such materials minimize thermal destruction or deletion of the desired image.

The following examples further describe the present invention with reference to the thermally induced imagewise Conversion of image parts of a layer of imaging material, which is a material with cholesteric, liquid-crystalline Features, from the "grandjean" or "disturbed" texture to a pictured, focal-conical or "undisturbed" texture. The parts and percentages represent parts by weight and percentages by weight, respectively, unless otherwise is specified. The following examples are intended to provide various preferred embodiments of the new liquid

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- Ίο -

'Illustrate the crystal imaging system.

B e i s ρ i e 1 1

An imaging 2-part is made by dissolving a dissolved mixture containing about 57 $> cholesteryl formate and about 43 9 ^ cholesterylnon & noat in the solvent petroleum ether, mixing the solution carefully and depositing a layer of the solution on a thick, stable, black plastic substrate. The solvent is allowed to evaporate, leaving a layer of the imaging composition containing cholesteric, liquid crystalline materials, about 12 / rev in thickness on the substrate. After evaporation of the solvent, the picture of the imaging composition is uniformly brought into the state of "Grandjean" texture by applying shear forces to the film, which is done by pulling the edge of a sheet of glass over the surface of the film. The film is green in color. The imaging part is then provided with an image using the texture transition imaging system by placing the part with the imaging composition facing upwards, a few µs apart, under an image-like metal mask and the masked part about 25 cm away from a BH6- 1 mercury arc lamp. The lamp is activated, which means that the part is exposed through the mask for an exposure time of around 10 seconds. The imagewise exposure heats the image areas to temperatures around or above the cholesteric, liquid-crystalline / liquid-isotropic transition temperature of the imaging composition, and the imaged areas exhibit a texture transition. A clearly optically distinguishable image, corresponding to the mask, of almost colorless image areas on a green-colored background appears almost instantly when exposed. The composition is left in its temperature range of its cholesterol

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cool liquid-crystalline mesophase.

The imaged areas have the focal-conical or "undisturbed" texture state , while the background areas of the cholesteric, liquid-crystalline imaging composition have the "Grandjean" or "disturbed" texture state.

Be i s pie I

Following the method of Example 1, an illustrated part is created. After the illustration, this illustrated part becomes covered with a transparent sheet of glass. The glass sheet becomes light in relation to the substrate of the imaged part postponed. The shifting of the cover plate deletes the image that has been illustrated by transforming the texture and creates the uniform cholesteric liquid crystalline imaging composition in "Grandjean" texture condition.

example

An image part is produced by mixing about 57 % cholesteryl formate and about 43 ° ß> cholesteryl nonanoate, placing the mixture in a crucible and bringing the mixture above the liquid-isotropic transition temperature of the mixture

■ α

and its components are heated. The liquid mixture is carefully mixed in the crucible while the composition is in the liquid state. The liquid composition is applied to a transparent glass substrate and becomes a a substantially uniform layer of imaging composition about 19 / u thick. the Composition is allowed in the temperature range of their cholesteric, liquid-crystalline mesophase cool, and the part is as described in Example 1, with a Image provided.

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- 2ο - 220Ü42A

The illustrated part is examined under a microscope, it can be seen that the image surfaces correspond to the focal-conical or "undisturbed" Have texture state and are colorless, while the background areas are green in color and im "Grandjean" or "disturbed" texture condition.

Example 4

An illustrated part is created according to the method of Example 3. After the illustration, the illustrated part is created with covered by a transparent sheet of glass. Pressure is exerted on the entire surface of the disc, which is achieved by transforming the texture formed image is erased and uniformly the cholesteric, liquid-crystalline imaging composition is created in the "Grandjean" texture state.

Example 5 to 7

As described in Example 1, imaging parts are created, with the exception that the dissolved mixture contains:

Example 5: About 30 # cholesteryl formate and about 70 $ Cholesteryl nonanoate.

Example 6: About 70 % cholesteryl formate and about 30% cholesteryl nonanoate.

Example 7s About $ 76 cholesteryl formate and about $ 24 cholesteryl nonanoate.

The imaging parts are as described in Example 1, provided with an image, which clearly optically distinguishable images results. The image parts are erased according to the method described in Example 2.

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Examples 8 to 90

Imaging parts are produced as described in the examples, with the exception that the imaging composition, which has cholesteric, liquid-crystalline properties, . the following contains:

; Example 8: ^v Approximately 74 ⁰ ₀ J Cholssterylchlorid and about 26 <o?

Cholesteryl acetate,

EXAMPLE 9 About 68 # cholesteryl chloride and about 32 ^a ß> ι cholesteryl acetate.

Example 10: About 60 ^o ß> cholesteryl chloride and about $ 40; Cholesteryl acetate.

: Example 11: 90 ^ cholesteryl chloride and about 10 fo • cholesteryl laurate.

Example 12: About $ 82 cholesteryl chloride and about $ 18 cholesteryl laurate.

Example 13: About $ 76 cholesteryl chloride and about $ 24>; Cholesteryl laurate.

Example H: About $ 93 cholesteryl chloride and about 7 % cholesteryl propionate.

Example 15: About 89 "/> cholesteryl chloride and about 11 % , cholesteryl propionate.

Example 16: About 80 ⁰ Jo cholesteryl chloride and about 20 fi Cholesterylhexanoat.

Example 17: About 70 % cholesteryl chloride and about 30 % cholesteryl hexanoate.

2 0 9 8 3 0/1117

; Example 18: About 91 έ cholesteryl chloride and about $ 9 'cholesteryl.

Example 19: About 87 l * cholesteryl chloride and about 13 # cholesteryl stearate.

Example 20: About 79 # cholesteryl chloride and about 21 # ^: cholesteryl stearate.

Example 21: About 84 # cholesteryl chloride and about 16 # Cholesteryl myristate.

Example 22: About 78 % cholesteryl chloride and about 22 $> ! Cholesteryl myristate.

'Example 23: About $ 10 cholesteryl chloride and about # 90

Cholesteryl oleyl carbonate.

Example 24: About 20 $ cholesteryl chloride and about 80 ⁰ Jo Cholesteryloleylcarbonat.

Example 25: About 30 ° ß> cholesteryl chloride and about 70 $> cholesteryl oleyl carbonate

Example 26: About 40 µl cholesteryl chloride and about 60 $ cholesteryl oleyl carbonate.

Example 27: About 66 # cholesteryl chloride and about 34 % cholesteryl oleyl carbonate.

'Example 28: About 71 <$> cholesteryl chloride and about 29 ° i

Cholesteryl oleyl carbonate.

Example 29: About 80 # cholesteryl chloride and about 20 μl cholesteryl oleyl carbonate.

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Example 3.0: About 90 fo Ciiolesterylchlorid and about 10 $ Cholesteryloleylcarbonat.

Example 31: About 88 # cholesteryl chloride and about 12 $ Cholesterylcaprj ^ lat «,

Example 32: About 80 fo cholesteryl and etwa'20 $> ^v Cholesterylcaprylat.

Example 33: About 80 fo cholesteryl chloride and about 20 $ cholesteryl iodide,

Example 34: About 50 % cholesteryl chloride and about 50% cholesteryl iodide.

Example 35: About $ 20 cholesteryl chloride and about 50 % cholesteryl iodide

Example 36: About $ 80 cholesteryl chloride and about $ 20

Cholesteryl 2- (2-butoxyethoxy) ethyl carbonate,

Example 37: About 70 # cholesteryl chloride and about 30 $>

Cholesteryl 2- (2-botoxyethoxy) ethyl carbonate,

Example 38: About 40 # cholesteryl chloride and about 60 $

Cholesteryl 2- (2-butoxyethoxy) ethyl carbonate.

Example 39: About $ 30> Cholesteryl Chloride and About 70 #

Cholesteryl 2- (2-butoxyethoxy) ethyl carbonate.

Example 40: About 30 ⁰ Jo cholesteryl chloride and about 70 $ cholesterylnonanoate.

Example 41: About 42 $ cholesteryl chloride and about 58 # Cholesteryl nonanoate ",

209830/1117

Example 42: About $ 49 cholesteryl chloride and about $ 51 Cholesteryl nonanoate.

Example 43: About $ 54 Cholesteryl Chloride And About 46 # Cholesteryl nonanoate.

Example 44: About 75 # cholesteryl chloride and about 25 # Cholesteryl nonanoate.

Example 45: About $ 80 cholesteryl chloride and about $ 20 Cholesteryl nonanoate.

Example 46: About $ 90 cholesteryl chloride and about $ 10 . Cholesteryl nonanoate.

Example 47: About $ 72 cholesteryl chloride and about # 28 Cholesteryl heptanoate.

Example 48: About $ 80 Cholesteryl Chloride and About 20 # Cholesteryl heptanoate.

Example 49: About 86 56 cholesteryl chloride and about 1 <j # Cholesteryl heptanoate.

Example 50: About $ 10 cholesteryl chloride and about 90% Cholesteryl bromide.

Example 50: About 20 $> cholesteryl chloride and about 80 ^c ß> Cholesterylbromid.

Example 52: About 30 <$> cholesteryl chloride and about 70 # cholesteryl bromide.

Example 53: About 50 fo cholesteryl and etv / a 50 ° ß> Cholesterylbroinid.

209830/1 1 17

'Example 54: About 66 % cholesteryl chloride and about 34%

Cholesteryl butyrate.

Example 55: About 74 % cholesteryl chloride and about 26 "

Cliolesteryl biityrate.

; Example 56: About 80 % cholesteryl chloride and about $ 20

Cholesteryl butyrate.

Example 57: About 73 # cholesteryl chloride and about 27 # Cholesteryl caproate.

j Example 58: About 83% Cliolesterylchlorid and about 17 $>'. Cholesteryl caproate.

^; Example 59: About 89 # cliolesteryl chloride and about "11 56 'cholesteryl caproate.

Example 60: About 80 % cholesteryl chloride and about 20% cholesterol.

Example 61: About 90 % cholesteryl chloride and about $ 10> cholesterol.

Example 62: About 68 % cholesteryl chloride and about 32 % cholesteryl valerate.

Example 63: About 74 # cholesteryl chloride and about 26 <fo

Cholesteryl valerate.

Example 64: About $ 84 Cholesteryl Chloride And About 16 # Cholesteryl valerate.

Example 65: About 55 fo cholesteryl chloride and about 45 $

Cholesteryl 2- (2-ethoxy-ethoxy) -ethyl carbonate,

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Example 66: About 20 $ cholesteryl UNAE about 80 i "

Cholesteryl 2- (2-ethoxy-ethoxy) -ethyl carbonate.

Example 67: About $ 10 cholesteryl chloride and about $ 90>

Cholesteryl 2- (2-ethoxy-ethoxy) -ethyl carbonate.

Example 68: About $ 50 cholesteryl n-propyl carbonate and about 50 # Cholesteryl-2- (2-ethoxy-ethoxy) ~ ethyl carbonate.

Example 69: About 68 # cholesteryl n-propyl carbonate and etv / a

32 # Cholesteryl-2- (2-ethoxy-ethoxy) -ethylj carbonate.

Example 70: About 20 % cholesteryl n-propyl carbonate and about 80 # cholesteryl 2- (2-butoxyethoxy) ethyl carbonate.

Example 71: About 15 # Cholesteryloleylcarbonat and etv; a i 85 ° anisylidene-p-butylaniline (hereinafter referred abuta).

Example 72: About $ 20 cholesteryl oleyl carbonate and about $ 80 ABUTA.

Example 73: About $ 27 cholesteryl oleyl carbonate and about 73 1 »ABUTA.

Example 74: About 35 " cholesteryl oleyl carbonate and about 65 # ABUTA.

Example 75: About $ 80> cholesteryl oleyl carbonate and about 20 1 * ABUTA.

Example 76: About $ 80 cholesteryl oleyl carbonate and about 20 # cholesterol.

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Example JT: About 90 # cholesteryl oleyl carbonate "and about
$ 10> cholesterol.

Example 73: About 10 $ cholesterol and about 45 <fo Cholesteryloleylcarbonat and about 45 $ cholesteryl-2- (2-ethoxy-ethoxy) -äthylcarbonat <,

Example 79; About $ 20> cholesterol and about $ 40> cholesteryl oleyl carbonate and about 40 % cholesteryl oleyl carbonate and about $ 40 cholesteryl 2- (2 ~ ethoxyethoxy) ethyl carbonate _e

Example 80: About $ 10 cholesterol and about $ 45 cholesteryl oleyl carbonate and about 45 % cholesteryl chloride "

Example 81: Approximately 20 fo cholesterol and about 40 and about 40% fo Cholesteryloleylcarbonat cholesteryl.

Example 82: About 72 $ cholesteryl chloride and about 14 %
Cholesteryl propionate and about Η $
Cholesteryl decanoate.

Example 83: About 76 # cholesteryl chloride and about 12 ^

Cholesteryl propionate and about $ 12 cholesteryl decanoate.

Example 84: About 80 # cholesteryl chloride and about 10 $>

Cholesteryl propionate and about 10 % cholesteryl decanoate.

Example 85: About $ 84 gholesteryl chloride and about $ 8

Cholesteryl propionate and about $ 8 cholesteryl decanoate.

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example

About 88 ^a / o cholesteryl chloride and about 6 $ cholesteryl propionate and about 6 $ cholesteryl decanoate.

Example 87:

About 38 ^c / o cholesteryl chloride and about 38 ⁰ Jo cholesteryl butyrate and about 13 $ Cholesterylformiat and about 13 $ Cholesteryldecanoat.

Example 88:

About 40 $ cholesteryl chloride and about 40 $ cholesteryl butyrate and about 10 $ cholesteryl formate and about 10 fo cholesteryl decanoate.

example

About 42 % cholesteryl chloride and about 42 $ cholesteryl butyrate and about 8 $ cholesteryl formate and about 8 $ cholesteryl decanoate.

Example 90:

About 44 $ cholesteryl chloride and about 44 Io cholesteryl and about 6 $ Cholesterylformiat and about 6 $ Cholesteryldecanoat.

Parts depicting me are provided with an image as described in Example 1, and clear, optically distinguishable ones are obtained Pictures. The illustrated parts are erased according to the methods described in Examples 2 and 4.

Any of the compositions of Examples 1 and 5 to 90 can Cross-other materials are used in imaging layers of various thicknesses and on thinner substrates, whereby Usually the irradiation times and the resulting irradiation energies can be changed. Compare Example 91 below.

209830/1 1 17

e i g e 91

An imaging member is prepared by the method of Example 3, wherein the imaging composition contains about 20 ° /> abuta and about 80 # Cholesteryloleylcarbonat. An image light of about 12 / U thickness on an approx

, 0.0508 mm (2 mil) thick black Tedlar substrate - a

[ DuPont polyvinyl fluoride resin film - manufactured. The imaging composition layer is sheared and imaged as in Example 1, irradiating with a for about 50 microseconds

• Total energy of about 10 millijoules / cm area of the imaging Layer. With this system one obtains optically

! distinguishable clear image on a blue colored background.

Although in the above description of the preferred embodiments of the thermally induced texture transition liquid-crystalline imaging system specific components and proportions have been given, others may as well appropriate materials and variations of the various steps in this system with satisfactory results and of various quality. Also, other materials and steps can be added to those used here v / ground, and the method can be varied to achieve synergistic effects or the invention to promote or otherwise modify. For example, numerous other mixtures of liquid crystals can also be used. stalls that are subject to the image-like texture transformation, found and used in the system of the present invention, such mixtures being slightly different thicknesses, Temperature ranges and other imaging conditions may be required for preferred results in accordance with the invention. Likewise, other devices for addressing the imaging parts with satisfactory results in the present invention can be used.

2 0 9 8 3 0/1117

Claims (1)

- 3ο - PATENT CLAIMS; Imaging method, characterized in that a layer of imaging material which comprises a material which has a cholesteric, liquid-crystalline mesophase, is created and this layer is in the temperature range of choiesteric, liquid-crystalline mesophase of the material and in the "Grandjean" texture state is provided; Energy is applied, which is able to produce a thermal effect in the imaging layer, creating image-like Parts of the imaging layer are influenced so that the temperature of the image-like parts of the imaging material is raised to a temperature of at least about the choiesteric, liquid-crystalline mesophase / liquid-isotropic transition temperature; and the bi-like parts of this imaging material on a Temperature in the temperature range of the choiesteric, liquid-crystalline mesophase of this material are cooled, whereby these image-like parts of the imaging layer assume the focal-conical texture state and thus the imaging one Layer has an image. 2. The method according to claim 1, characterized in that the layer of imaging material is provided on a carrier substrate. 3. The method according to claim 2, characterized in that the carrier substrate is substantially transparent. 2 0 9 8 3 0/1117 Yy. Method according to Claim 2 _S, characterized in that the carrier substrate is opaque. 5. The method according to any one of claims 1 to 'J _5, characterized in that the layer of imaging material is covered with a transparent coating. 6. The method according to claim 5 _9, characterized in that the transparent coating is no thicker than about 0.25 * 1 mm (10 mils). 7 ο "Method according to claims 1 to 6, characterized in that that the layer of imaging material is no thicker than about 250 u. 8. The method according to claim 7 _S, characterized in that the imaging composition has a thickness in the range between about 1 and about 50 u, 9. The method according to claims 1 to 8 _9, characterized in that the on the layer of imaging material applied energy in the range between about 1 millijoule / cm ρ
and about 100 millijoules / cm of surface area of the layer. 10. The method according to any one of claims 1 to 9 »characterized in that the energy in an image-like configuration is applied to the layer of imaging material. 11. The method according to claim 1O ₉ , characterized in that the layer of imaging material is not thicker than about 250 , u and the applied energy in the range between about 1 millijoule / cm and about 100 millijoules / cm ² surface of the layer. 209830/1117 12. "The method according to claim 10 or 11, characterized in that the energy is generated by irradiating the layer of imaging Material with radiant energy is applied through a mask in an image configuration. 13. The method according to claim 12, characterized in that a gas discharge lamp is used as the source for the radiant energy is used. 1 ^ J. Method according to claim 12 or 13, characterized in that that the exposure time is no more than about 10 seconds. · 15. The method according to claims 1 to 1 * 1, characterized in that that the imaging material is a mixture of a material that is a cholesteric, liquid-crystalline Has mesophase, and at least one material selected from materials with a nematic, liquid-crystalline mesophase, materials with a smectic, liquid crystalline mesophase and mixtures thereof. 16. The method according to claims 1 to 15, characterized in that the imaging material in the temperature range between about 20 ° C and about 30 ⁰ C comprises cholesteric liquid-crystalline properties. 17. The method according to claims 1 to l6, characterized in that the imaged material between polarizers is viewed with transmitted light and the transparent substrate is optically isotropic. 18. The method according to claims 1 to 17, characterized 2 0 9 8 3 0/1117 -33- 220CM24 characterized in that the layer of imaging material has one in the visible spectrum. 19. Imaging method, characterized in ₉
that (a) a layer of imaging material according to the process of claims 1 to 18 is provided and provided with an image and (b) thereafter, an external force uniformly acts on this imaging part to erase the image _f ~ by ^
the layer of imaging material uniformly in the
"Grandjean" text is brought to its original state. 20. Repeatable imaging method, characterized in that steps (a) and (b) according to claim 18
repeated several times using the same layer of imaging material. 209830/1 117 Blank page