US3816113A - Nematic liquid crystalline compositions having extended mesomorphic range - Google Patents

Nematic liquid crystalline compositions having extended mesomorphic range Download PDF

Info

Publication number
US3816113A
US3816113A US00179731A US17973171A US3816113A US 3816113 A US3816113 A US 3816113A US 00179731 A US00179731 A US 00179731A US 17973171 A US17973171 A US 17973171A US 3816113 A US3816113 A US 3816113A
Authority
US
United States
Prior art keywords
liquid crystalline
crystalline material
electric field
compositions
electrodes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00179731A
Inventor
W Haas
J Flannery
B Mechlowitz
J Adams
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xerox Corp
Original Assignee
Xerox Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xerox Corp filed Critical Xerox Corp
Priority to US00179731A priority Critical patent/US3816113A/en
Priority to CA143,111A priority patent/CA1003632A/en
Priority to DE2235387A priority patent/DE2235387A1/en
Priority to JP47078270A priority patent/JPS4837380A/ja
Priority to GB4231972A priority patent/GB1410221A/en
Priority to NL7212433A priority patent/NL7212433A/xx
Priority to FR7232465A priority patent/FR2248084A1/fr
Application granted granted Critical
Publication of US3816113A publication Critical patent/US3816113A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/135—Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/10—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings
    • C09K19/22—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing at least two benzene rings linked by a chain containing carbon and nitrogen atoms as chain links, e.g. Schiff bases
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F13/00—Illuminated signs; Luminous advertising

Definitions

  • Kelker et al. A Liquid-Crystalline (Nematic) Phase with a Particularly Low solidification Point, Angew. Chem. Internat. Edit, Vol. 8, No. 11, pp. 884-885 (1969).
  • NEMATIC LIQUID CRYSTALLINE COMPOSITIONS HAVING EXTENDED MESOMORPIIIC RANGE BACKGROUND OF THE INVENTION This application relates generally to liquid crystalline compositions. More particularly the invention relates to such compositions having extended nematic mesomorphic temperature ranges which are stable at relatively low temperatures and their use in electro-optic applications.
  • Liquid crystalline substances exhibit physical characteristics some of which are typically associated with liquids and others which are typically unique to solid crystals.
  • the name liquid crystals has become generic to substances exhibiting these dual properties.
  • Liquid crystals are known to appear in three different forms: the smectic, nematic and cholesteric. These structural forms are sometimes referred to as mesophases thereby indicating that they are states of matter intermediate between the liquid and crystalline states.
  • the three mesophase forms of liquid crystals mentioned above are characterized by different physical structures wherein the molecules of the compound are arranged in a structure which is unique to each of the three me somorphic structures. Each of these structures is well known in the liquid crystal art.
  • the molecules are arranged in layers with their major axes approximately parallel to each other and approximately normal to the planes of the layers. Within a given layer the molecules may be organized in uniform rows, or randomly distributed throughout the layer, but in either case the major axes are still approximately normal to the plane of the layer.
  • the attractive forces between layers are relatively weak so that layers are free to move in relation to each other thereby providing the smectic liquid crystalline substance with the mechanical properties of a planar or two-dimensional, soap-like fluid.
  • the major axes of the molecules lie approximately parallel to each other but the molecules are not organized into definite layers as is the case in the smectic structure.
  • nematic liquid crystals The sensitivity of the optical properties of nematic liquid crystals to electric fields makes these materials extremely useful for electro-optical applications.
  • dynamic scattering is common to many materials which exhibit nematic liquid crystalline mesophases.
  • the so-called dynamic scattering state occurs when an ionic current flow is set up through the nematic liquid crystalline material and the nematogenic material assumes a non-selective light-scattering appearance. This phenomenon may be utilized in electro-optical .devices' such as, for example, display systems.
  • ABUTA pmethoxybenzylidene-p-n-butylaniline
  • R CH and R C I-I has a nematic mesomorphic range of from about 20C to about 41C. While this compound has been found to be very useful in various electro-optic techniques nevertheless there exists a continuing need for liquid crystalline materials which have a nematic mesophase at or near room temperature.
  • Yet another object of the invention is to provide such liquid crystalline compositions which are useful in electro-optical applications.
  • a still further object of the invention is to provide such liquid crystalline compositions which may be utilized in electro-optic display devices.
  • Liquid crystalline compounds which belong to the class of compounds having the general formula and wherein R, and R are particular combinations of alkyl groups are disclosed in copending application Ser. No. 179,732, filed Sept. 13, 1971 now abandoned, on the same day as the present application and hereby incorporated by reference herein.
  • the compounds disclosed in the copending application are listed in Table I below:
  • compositions of the invention are highly advantageous when employed in various electro-optic applications since they allow overall device considerations to be desirably simplified.
  • novel compositions of the invention may be conveniently utilized in any number of electro-optic applications such as for example, display cells since upon application of an electric field of sufficient magnitude, e.g., above about 3,000 volts/cm, the optical properties of the materials change and the liquid crystal material which is substantially transparent prior to the application of the field becomes frosted, i.e., exhibits dynamic scattering.
  • an electric field of sufficient magnitude e.g., above about 3,000 volts/cm
  • FIG. 1 through FIG. 7 are graphical plots illustrating the eutectic behavior of the respective compositions of the invention with respect to varying mol fractions of the individual components thereof;
  • FIG. 8 is a partially schematic cross-sectional view of a liquid crystalline imaging member
  • FIG. 9 is a partially schematic isometric view of an embodiment of a liquid crystalline imaging member wherein the desired image is defined by the shape of at least one of the electrodes;
  • FIG. 10 is a partially schematic isometric view of an embodiment of a liquid crystalline display device.
  • FIG. 11 is a partially schematic cross-sectional view of an embodiment of a liquid crystalline imaging member wherein at least one of the electrodes has a photoconductive surface.
  • compositions of the invention are prepared by condensation in refluxing ethanol of the respective p-nalkoxybenzaldehyde and the appropriate p-nalkylaniline. Refluxing is carried for several hours and the solvent is then removed by distillation. The crystalline products are then purified by repeated recrystallization from an appropriate solvent such as methanol or petroleum ether.
  • an appropriate solvent such as methanol or petroleum ether.
  • the compositions are prepared by weighing appropriate fractions of the desired constituents, combining them in a vessel, e.g., a glass beaker, and heating above'the isotropic transition temperatures of the respective constituents with mixing to ensure a homogeneous composition.
  • the temperatures at which transitions from the nematic mesomorphic state to the isotropic state occur are determined by differential thermal analysis employing a DuPont 900 Differential Thermal Analyzer equipped with chrome] alumel thermocouples.
  • the therrnograms are obtained at a heating rate of 10C/minute and the temperature at the beginning of the state transition endotherm is taken as the characteristic temperature.
  • the temperature is determined by linear extrapolation of the leading edge of the endotherm to its intersection with the baseline.
  • FIG. 1 there is seen a graphical plot illustrating the eutectic behavior of compositions prepared from varying mol fractions of BOBUTA and ABUTA.
  • the nematic mesomorphic temperature range for BOBUTA is from about 46C to about C and that for ABUTA from about 20C to about 41C. It can be seen that the compositions possess extended nematic mesomorphic temperature ranges which generally increase progressively as the weight percent of the BOBUTA increases and which reach a maximum at frorn about S Sto about 65 weight percent BOBUTA.
  • FIG. 2 illustrates the eutectic behavior of compositions prepared from varying weight percentages of EOBUTA and ABUTA.
  • the nematic mesomorphic temperature range for EOBUTA is from about 38C to about 82C.
  • FIG. 3 illustrates the eutectic behavior of compositions prepared from varying weight percentages of BOBUTA and EOBUTA.
  • the compositions are seen to have extended nematic mesomorphic temperature ranges which reach a maximum at from about 55 to about 75 weight percent of EOBUTA.
  • BOETHA has a nematic mesomorphic range of from about 48C to about 625C.
  • the compositions have extended nematic mesomorphic temperature ranges which generally increase rapidly as the proportion of the ABUTA constituent increases and which reach a maximum at from about 60 to about 80 weight percent of ABUTA.
  • FIG. 5 illustrates the eutectic behavior of compositions prepared from varying weight percentages of B0- ETHA and EOBUTA.
  • the compositions have extended nematic mesomorphic temperature ranges which reach a maximum at from about 70 to about 90 weight percent EOBUTA.
  • FIG. 6 graphically illustrates the eutectic behavior of compositions prepared from varying weight percentages of PENTOBUTA and ABUTA.
  • PENTOBUTA has a nematic mesomorphic temperature range of from about 54 to about 71C.
  • the compositions have extended mesomorphic temperature ranges which generally increase rapidly as the proportion of the ABUTA constituent increases and which reach a maximum at from about 50 to about 80 weight percent of ABUTA.
  • HEXOBUTA has a nematic mesomorphic temperature range of from about 70 to about 78C.
  • the compositions are seen to have extended nematic mesomorphic temperature ranges which generally become larger as the proportion of the ABUTA constituent increases and which reach a maximum at from about 50 to about 70 weight percent of ABUTA.
  • novel compositions of the invention may be utilized in a variety of electrooptic devices and provide simplified apparatus considerations therefore because of their stability at room temperature or below.
  • FIG. 8 illustrates a typical liquid crystalline electrooptic cell in which the novel compounds of the invention may be utilized.
  • a liquid crystalline electro-optic cell 10 sometimes referredto as an electroded imaging sandwich, which is shown in partially schematic cross-section and wherein a pair of plates, generally designated 12, comprise a parallel pair of electrodes at least one of which is substantially transparent.
  • An electro-optic cell wherein both electrodes are transparent is preferred when the cell is to be viewed using transmitted light; however a liquid crystalline electro-optic cell may also be viewed using reflected light thereby requiring only a single transparent electrode while the other is opaque.
  • electrodes 12 are shown as being substantially transparent and are comprised of, in this illustrative instance, a substantially transparent conductive layer 13 upon the contact surface deposited on a transparent support member 14.
  • a typical suitable electrode for use in electro-optic cell 110 is commercially available under the name NESA glass from Pittsburgh Plate Glass Company and is made up of a thin transparent electrically conductive layer of tin oxide overlying a transparent glass substrate.
  • the transparent electrodes 12 are separated by spacing member 16 which contains voids which form one or more shallow cups which contain the liquid crystalline film or layer 117 which comprises the active element of the electro-optic cell.
  • Liquid crystalline film 17 may be comprised of any of the novel liquid crystalline compounds of the invention or mixtures thereof.
  • a field is created between the electrodes by means of an external circuit, generally designated 18 which typically comprises a source of potential 20 which is connected across the two electrodes through leads 22.
  • the circuit 118 may also contain suitable switching means.
  • the potential source 20 may be either D.C., A.C., or a combination thereof.
  • the electro-optic cell can function as a light shutter since a large percentage (e.g. about percent of incident light would be scattered and removed from the incident light while only a small percentage, e.g., about 10 percent would be transmitted.
  • the electrodes may be of any suitable transparent conductive material.
  • suitable transparent, conductive electrodes include glass or plastic substrates having substantially transparent and continuous conductive coatings of conductors such as tin, indium oxide, aluminum, chromium, tin oxide or any other suitable conductor. These substantially transparent conductive coatings are typically evaporated onto the more insulating transparent substrate. Where an opaque electrode is employed in the electro-optic cell any suitable electrode material may be used.
  • the spacer 16, which separates the transparent electrodes and contains the liquid crystal film 17 between the electrodes is typically chemically inert, transparent, substantially insulating and has appropriate dielectric characteristics.
  • Materials which are suitable for use as typical insulating spacers include cellulose acetate, cellulose triacetate, cellulose acetate butyrate, polyurethane elastomers, polyethylene, polypropylene, polyesters, polystyrene, polycarbonates, polyvinylfluoride, polytetrafluoroethylene, polyethylene terephthalate, and mixtures thereof.
  • These spacers which also approximately define the thickness of the imaging layer or film 17 of liquid crystalline material, are preferably of a thickness in the range of about ll) mils or less. Optimum results are typically attained with spacers in the thickness range between about A mil and about 5 mils.
  • FIG. 9 describes a liquid crystalline electro-optic imaging cell.
  • the desired image is defined by the shape of an electrode and, therefore, by the shape of the corresponding electric configuration; however it will be understood by those 10 skilled in the art that both electrodes could easily be made in a matched pair to define the same desired image.
  • the second electrode will comprise transparent substrate 14 with substantially transparent conductive 15 coating 13 upon the entire area of the inner surface of the transparent electrode. It is noted that a very thin, or substantially invisible conductor 28 is typically used in this embodiment to electrically connect the electrode in the desired image configuration to an external circuit which is similarly connected to the conductive coating of the opposite electrode.
  • this embodiment will produce an electric field only in areas where there are parallel electrodes, i.e., between the electrode in the desired image configuration and the opposite electrode, whether or not the second electrode is also in the desired image configuration.
  • one of the electrodes may be opaque if it is desired to observe the imaged cell by reflected light rather than transmitted light.
  • an electrode may be shaped in the configuration of the background of the desired image and an imagewise electrode and such a corresponding background electrode may be coplanar 5 and insulated from one another by an open space or insulating material.
  • Such a coplanar pair of electrodes may be operated simultaneously as a substantially fullarea electrode.
  • FIG. 10 describes a preferred embodiment of a liquid crystalline imaging cell embodying an x-y grid and comprising two transparent planar substrates 32 and 34 which are parallel.
  • On the inner surface 36 of substrate 32 are arranged an array of transparent conductive strips all running in one direction. Four strips or electrodes, designated 38a, 38b, 38c, 38d, and which have parallel longitudinal axes are shown; however it will be understood that in actual practice a much larger number of electrodes may be used.
  • On the inner surface 40 of substrate 34 are arranged an array of transparent conductive electrodes 42a, 42b, 42c, 42d having parallel longitudinal axes and being positioned substantially perpendicularly to the direction of the conductive strips 38a-38d on substrate 32. Again it will be understood that in actual practice a much larger number of electrodes may be arranged on inner surface 40 of substrate 34.
  • the space between substrates 32 and 34 is filled with liquid crystalline which can be any of the novel compounds of the invention or mixtures thereof.
  • FIG. ll describes still another preferred embodiment of a liquid crystalline electro-optic imaging cell wherein one of the electrodes comprises a photoconductor and imaging is effected by applying a uniform potential across the entire area of the electrodes and subsequently exposing the photoconductor to an imagewise pattern of activating electromagnetic radiation corresponding to a desired image configuration.
  • an electro-optic imaging cell generally designated 50, wherein a pair of plates, generally designated 52 and 54 respectively, comprise a parallel pair of electrodes at least one of which is substantially transparent. For purposes of illustration both electrodes are shown as being transparent.
  • Electrode 52 is made up of a photoconductive insulating material layer 53 overlying a conductive substrate which in this instance is shown as a substantially transparent conductive layer 51 deposited on a substantially transparent support member 55. Electrode 54 is shown as a substantially transparent conductive layer 56 deposited on substantially transparent substrate 57.
  • both electrodes be substantially transparent.
  • a photoconductive insulating material layer which is substantially transparent to the activating electromagnetic radiation.
  • suitable substan tially transparent photo-conductive materials include, for example, relatively thin, e.g., about 5 microns, layers of selenium.
  • the electro-optic imaging cell may also be viewed using reflected light thereby requiring only a single transparent electrode while the other may be opaque.
  • one of the electrodes is preferably made up of an opaque photoconductive insulating layer deposited on an opaque substrate which may be any suitable conducting material such as a metallic layer.
  • the transparent electrodes are separated by spacing member 16 which contains voids which form one or more shallow cups which contain the liquid crystalline film or layer ll7.
  • the electrodes are connected to opposite terminals of an external circuit 18.
  • an external circuit 18 When a potential is applied to the conducting surface 51 of electrode 52 in the dark no current will flow and no field will be established across the liquid crystal film since layer 53 is insulating under these conditions.
  • the light-struck areas of photoconductive insulating layer 53 become conductive causing current to flow and establishing a field across the liquid crystal film in the light-struck areas.
  • the electric field causes the optical properties of the liquid crystalline material to change and the liquid crystal film, which is substantially transparent prior to the application of the field, becomes frosted, i.e., exhibits dynamic scattering thereby effecting imaging.
  • the imaging cell When the imaging cell is viewed by reflected light the image will typically appear as milky-white image areas on a dark background. When the imaging cell is viewed using transmitted light the image will typically appear as dark image areas with transparent non-image or background areas.
  • Liquid crystalline compositions comprising from about 55 to about 65 weight percent of and from about 35 to about 45 weight percent of 2.
  • Liquid crystalline compositions comprising about 50 to about 70 weight percent of and about 30 to about 50 weight percent of 7' Q 3.
  • Liquid crystalline compositions comprising about 60 to about 80 weight percent of and from about 20 to about weight percent of 4.
  • Liquid crystalline compositions comprising from about to about 80 weight percent of and from about 20 to about 50 weight percent of 5.
  • Liquid crystalline compositions comprising from about 50 to about 70 weight percent of and from about 30 to about 50 weight percent of applying an electric field across said liquid crystalline material, said electric field being of sufficient strength to transform said liquid crystalline material to a light-scattering state.
  • the liquid crystalline material is arranged between two electrodes at least one of which is substantially transparent.
  • liquid crystalline material shaped in image configuration between two electrodes at least one of which is substantially transparent, said liquid crystalline material comprising a composition of claim 1, and
  • liquid crystalline material comprising a composition of claim 1, and
  • liquid crystalline material comprising a composition of claim energizing said electrodes by applying a potential thereto
  • the method of producing a display comprising providing a display device comprising first and second spaced plates, at least one of which is substantially transparent, a plurality of parallel electrically conductive films on one face of said first plate, a plurality of parallel electrically conductive films on one face of said second plate, the plurality of conductive films on at least one plate being substantially transparent, said two plates being positioned with said faces bearing said parallel conductive films adjacent and parallel to each other and the direction of said conductive films on one plate being perpendicular to the direction of said conductive films on the other plate, and a liquid crystalline material comprising a composition of claim 1 filling the space between said plates, and

Abstract

Compositions formed from nematic liquid crystalline compounds are disclosed. The novel compositions of the invention have extended nematic mesomorphic temperature ranges which are significantly larger than those of the individual components of the compositions and are stable at relatively low temperatures.

Description

8o cats-$188113 United States Haas et a1.
[ NEMATIC LIQUID CRYSTALLINE COMPOSITIONS HAVING EXTENDED MESOMORPI-IIC RANGE [75] Inventors: Werner E. L. Haas; John B.
Flannery, In, both of Webster; Bela Mechlowitz, Rochester; James E. Adams, East Ontario, all of NY.
[73] Assignee: Xerox Corporation, Stamford,
[51] Int. Cl 603g 13/10, 603g 9/04, 0021' 1/28, G02f1/36, G03b 21/24, 350 160 LC 1 June 11, 1974 3,689,525 9/1972 Scheurle ct a1. 260/273 R FOREIGN PATENTS OR APPLICATIONS 1,170,486 11/1969 Great Britain 252/408 OTHER PUBLICATIONS Liquid Crystals Draw Intense Interest, Chemical and Engineering News, Nov. 1, 1971, pp. 20-23.
Kelker et al., A Liquid-Crystalline (Nematic) Phase with a Particularly Low solidification Point, Angew. Chem. Internat. Edit, Vol. 8, No. 11, pp. 884-885 (1969).
Primary ExaminerNorman G. Torchin Assistant Examiner.1. P. Brammer Attorney, Agent, or FirmJames .1. Ralabate; David C. Petre; Gaetano D. Maccarone [57] ABSTRACT 1 58 Field of Search 96/1; 252/408; 353/84 Compositions formed from nomatio liquid Crystalline compounds are disclosed. The novel compositions of [56 References Ci the invention have extended nematic mesomorphic UNITED STATES PATENTS temperature ranges which are significantly larger than 3 597 044 8/1971 C t H 350/160 LC those of the individual components of the composias e ano 362559' W97! Freiser t I I 350/160 LC trons and are stable at relatively low temperatures. 3,627,408 8/1971 Ferguson 353/84 11 Claims, 11 Drawing Figures 3 5 1, 5,1 3 .j 0am os/ta 1 7 s t alalellls MENTH'JJIII: 1 I m SHEEI t UP 5 ABUTA HEXOBUTA ISOTROPIC NEMATIC SOLID FIG. 7
NEMATIC LIQUID CRYSTALLINE COMPOSITIONS HAVING EXTENDED MESOMORPIIIC RANGE BACKGROUND OF THE INVENTION This application relates generally to liquid crystalline compositions. More particularly the invention relates to such compositions having extended nematic mesomorphic temperature ranges which are stable at relatively low temperatures and their use in electro-optic applications.
Liquid crystalline substances exhibit physical characteristics some of which are typically associated with liquids and others which are typically unique to solid crystals. The name liquid crystals" has become generic to substances exhibiting these dual properties. Liquid crystals are known to appear in three different forms: the smectic, nematic and cholesteric. These structural forms are sometimes referred to as mesophases thereby indicating that they are states of matter intermediate between the liquid and crystalline states. The three mesophase forms of liquid crystals mentioned above are characterized by different physical structures wherein the molecules of the compound are arranged in a structure which is unique to each of the three me somorphic structures. Each of these structures is well known in the liquid crystal art.
In the smectic structure the molecules are arranged in layers with their major axes approximately parallel to each other and approximately normal to the planes of the layers. Within a given layer the molecules may be organized in uniform rows, or randomly distributed throughout the layer, but in either case the major axes are still approximately normal to the plane of the layer. The attractive forces between layers are relatively weak so that layers are free to move in relation to each other thereby providing the smectic liquid crystalline substance with the mechanical properties of a planar or two-dimensional, soap-like fluid.
In the nematic structure the major axes of the molecules lie approximately parallel to each other but the molecules are not organized into definite layers as is the case in the smectic structure.
The sensitivity of the optical properties of nematic liquid crystals to electric fields makes these materials extremely useful for electro-optical applications. For example, dynamic scattering is common to many materials which exhibit nematic liquid crystalline mesophases. The so-called dynamic scattering state occurs when an ionic current flow is set up through the nematic liquid crystalline material and the nematogenic material assumes a non-selective light-scattering appearance. This phenomenon may be utilized in electro-optical .devices' such as, for example, display systems.
Heretofore a serious drawback with respect to potential uses of nematogenic materials in electro-optic devices has been the relatively high temperatures at which the majority of the known nematic materials become mesomorphic. Typically, electro-optic devices are operated at or near room temperature. Thus devices utilizing such nematic liquid crystalline materials would require additional apparatus to maintain the temperature of the liquid crystalline material within its mesomorphic range thereby undesirably complicating the overall device configuration.
Recently there was disclosed in the art a nematogenic material which is liquid crystalline at room temperature. H. Kelker and B. Scheurle, in Angew. Che., Inter. Ed. 8, 884 (1969), reported the preparation of pmethoxybenzylidene-p-n-butylaniline (ABUTA) which has the chemical formula:
where R CH and R C I-I and has a nematic mesomorphic range of from about 20C to about 41C. While this compound has been found to be very useful in various electro-optic techniques nevertheless there exists a continuing need for liquid crystalline materials which have a nematic mesophase at or near room temperature.
SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide liquid crystalline materials having the above-described desirable features.
It is another object of the invention to provide novel liquid crystalline compositions.
It is a further object of the invention to provide liquid crystalline compositions having nematic mesomorphic temperature ranges which are significantly larger than those of the individual components thereof.
It is a still further object of the invention to provide liquid crystalline compositions which have a nematic mesophase at or near room temperature.
Yet another object of the invention is to provide such liquid crystalline compositions which are useful in electro-optical applications.
A still further object of the invention is to provide such liquid crystalline compositions which may be utilized in electro-optic display devices.
These and other objects and advantages of the invention are accomplished by providing novel liquid crystalline compositions which are formed by mixing together liquid crystalline compounds having a general formula and which have a nematic mesophase which is stable at relatively low temperatures.
Liquid crystalline compounds which belong to the class of compounds having the general formula and wherein R, and R are particular combinations of alkyl groups are disclosed in copending application Ser. No. 179,732, filed Sept. 13, 1971 now abandoned, on the same day as the present application and hereby incorporated by reference herein. The compounds disclosed in the copending application are listed in Table I below:
TABLE I Bmeetle Nematlc R1 R2 0.) C.) Name C H1 CIHQ 39-59 p n-PropoxybenZylidene-p-nbutylaniline.
CIH'... (34H, 7-46 46-75 p-n-Butox benZyIidene-pmbutylaniline.
CaHn.-. 04H 24-54 54-71 p-qz-Pentyloxybenzyljdene-pn-butylaniline.
C.Hi;. ClHO 25-70 70-78 p-n-HexyloxybenZylidene-pnylani a M W..-
C1H 04H, 29-76 7677.5 p-n-T-IeptyloxybenzyIidene-pn-butylaniline.
C411,. CH; (49)-66 66-63 pm-Butoxybenzylidene-ptoluidine.
CH CzH5 42-52 52-67 p-rr-Butoxybenzyhdene-pethylaniline.
CBHIL-.. CH3 35-45 45-64 pm-Pentyloxybenzylidene-ptoluidine.
Denotes monotropic transition.
[(6552: seen that the novel compounds disclosed in the copending application each possess a nematic mesophase which is stable at relatively low temperatures, i.e., near room temperature. These compounds have been found to be highly advantageous for use in various electro-optic applications such as, for example, display devices.
Now it has been surprisingly found that by utilizing some of the compounds listed in Table l and otherv PENTOBUTA) and ABUTA; and mixtures of p-nhexyloxybenzylidene-p'-n-butylaniline (hereafter HEXOBUTA) and ABUTA. As will be seen below an extremely important characteristic of these novel compositions is that they typically have nematic mesophases which are stable at room temperature or slightly below and in some cases significantly below typically extending to below 0C.
Thus it will be recognized that the compositions of the invention are highly advantageous when employed in various electro-optic applications since they allow overall device considerations to be desirably simplified. The novel compositions of the invention may be conveniently utilized in any number of electro-optic applications such as for example, display cells since upon application of an electric field of sufficient magnitude, e.g., above about 3,000 volts/cm, the optical properties of the materials change and the liquid crystal material which is substantially transparent prior to the application of the field becomes frosted, i.e., exhibits dynamic scattering. For a detailed description of this phenomenon see G. H. Heilmeier et al., Proc. IEEE 56, 7 (1968).
The foregoing and other objects and advantages of the invention will be more readily understood from the following detailed description of preferred embodiments thereon particularly when viewed in conjunction with the accompanying drawings wherein:
FIG. 1 through FIG. 7 are graphical plots illustrating the eutectic behavior of the respective compositions of the invention with respect to varying mol fractions of the individual components thereof;
FIG. 8 is a partially schematic cross-sectional view of a liquid crystalline imaging member;
FIG. 9 is a partially schematic isometric view of an embodiment of a liquid crystalline imaging member wherein the desired image is defined by the shape of at least one of the electrodes;
FIG. 10 is a partially schematic isometric view of an embodiment of a liquid crystalline display device; and
FIG. 11 is a partially schematic cross-sectional view of an embodiment of a liquid crystalline imaging member wherein at least one of the electrodes has a photoconductive surface.
Generally speaking the individual compounds used to form the compositions of the invention are prepared by condensation in refluxing ethanol of the respective p-nalkoxybenzaldehyde and the appropriate p-nalkylaniline. Refluxing is carried for several hours and the solvent is then removed by distillation. The crystalline products are then purified by repeated recrystallization from an appropriate solvent such as methanol or petroleum ether. For a detailed description of the procedures used in forming these compounds see the copending application referred to earlier. The compositions are prepared by weighing appropriate fractions of the desired constituents, combining them in a vessel, e.g., a glass beaker, and heating above'the isotropic transition temperatures of the respective constituents with mixing to ensure a homogeneous composition.
The temperatures at which transitions from the nematic mesomorphic state to the isotropic state occur, as indicated in FIGS. 1 through 7 for the respective compositions, are determined by differential thermal analysis employing a DuPont 900 Differential Thermal Analyzer equipped with chrome] alumel thermocouples. The therrnograms are obtained at a heating rate of 10C/minute and the temperature at the beginning of the state transition endotherm is taken as the characteristic temperature. The temperature is determined by linear extrapolation of the leading edge of the endotherm to its intersection with the baseline.
Verification of the state assignments is obtained by polarized optical miscoscopy. Samples of these compositions are placed in the form of thin films, between glass cover slides and viewed through a Leitz Ortholux polarizing microscope having a calibrated hotstage. Visually observed texture changes have been found to coincide within 2C with the phase transitions observed y. thermal na ys Referring now to FIG. 1 there is seen a graphical plot illustrating the eutectic behavior of compositions prepared from varying mol fractions of BOBUTA and ABUTA. The nematic mesomorphic temperature range for BOBUTA is from about 46C to about C and that for ABUTA from about 20C to about 41C. It can be seen that the compositions possess extended nematic mesomorphic temperature ranges which generally increase progressively as the weight percent of the BOBUTA increases and which reach a maximum at frorn about S Sto about 65 weight percent BOBUTA.
FIG. 2 illustrates the eutectic behavior of compositions prepared from varying weight percentages of EOBUTA and ABUTA. The nematic mesomorphic temperature range for EOBUTA is from about 38C to about 82C. The compositions possess extended nematic mesomorphic temperature ranges which reach a maximum at from about 50 to about 70 weight percent of ABUTA.
FIG. 3 illustrates the eutectic behavior of compositions prepared from varying weight percentages of BOBUTA and EOBUTA. The compositions are seen to have extended nematic mesomorphic temperature ranges which reach a maximum at from about 55 to about 75 weight percent of EOBUTA.
The eutectic behavior of compositions prepared from varying weight percentages of BOETHA and ABUTA is shown in FIG. 4. BOETHA has a nematic mesomorphic range of from about 48C to about 625C. The compositions have extended nematic mesomorphic temperature ranges which generally increase rapidly as the proportion of the ABUTA constituent increases and which reach a maximum at from about 60 to about 80 weight percent of ABUTA.
FIG. 5 illustrates the eutectic behavior of compositions prepared from varying weight percentages of B0- ETHA and EOBUTA. The compositions have extended nematic mesomorphic temperature ranges which reach a maximum at from about 70 to about 90 weight percent EOBUTA.
FIG. 6 graphically illustrates the eutectic behavior of compositions prepared from varying weight percentages of PENTOBUTA and ABUTA. PENTOBUTA has a nematic mesomorphic temperature range of from about 54 to about 71C. The compositions have extended mesomorphic temperature ranges which generally increase rapidly as the proportion of the ABUTA constituent increases and which reach a maximum at from about 50 to about 80 weight percent of ABUTA.
The eutectic behavior of compositions prepared with varying mol fractions of HEXOBUTA and ABUTA is illustrated in FIG. 7. HEXOBUTA has a nematic mesomorphic temperature range of from about 70 to about 78C. The compositions are seen to have extended nematic mesomorphic temperature ranges which generally become larger as the proportion of the ABUTA constituent increases and which reach a maximum at from about 50 to about 70 weight percent of ABUTA.
As was discussed previously the novel compositions of the invention may be utilized in a variety of electrooptic devices and provide simplified apparatus considerations therefore because of their stability at room temperature or below. I
FIG. 8 illustrates a typical liquid crystalline electrooptic cell in which the novel compounds of the invention may be utilized. Referring now to FIG. 8 there is seen a liquid crystalline electro-optic cell 10, sometimes referredto as an electroded imaging sandwich, which is shown in partially schematic cross-section and wherein a pair of plates, generally designated 12, comprise a parallel pair of electrodes at least one of which is substantially transparent. An electro-optic cell wherein both electrodes are transparent is preferred when the cell is to be viewed using transmitted light; however a liquid crystalline electro-optic cell may also be viewed using reflected light thereby requiring only a single transparent electrode while the other is opaque. For purposes of illustration both electrodes 12 are shown as being substantially transparent and are comprised of, in this illustrative instance, a substantially transparent conductive layer 13 upon the contact surface deposited on a transparent support member 14. A typical suitable electrode for use in electro-optic cell 110 is commercially available under the name NESA glass from Pittsburgh Plate Glass Company and is made up of a thin transparent electrically conductive layer of tin oxide overlying a transparent glass substrate.
The transparent electrodes 12 are separated by spacing member 16 which contains voids which form one or more shallow cups which contain the liquid crystalline film or layer 117 which comprises the active element of the electro-optic cell. Liquid crystalline film 17 may be comprised of any of the novel liquid crystalline compounds of the invention or mixtures thereof. A field is created between the electrodes by means of an external circuit, generally designated 18 which typically comprises a source of potential 20 which is connected across the two electrodes through leads 22. The circuit 118 may also contain suitable switching means. The potential source 20 may be either D.C., A.C., or a combination thereof.
When an electric field of sufficient magnitude, e.g. above about 3,000 volts/cm, is applied across the liquid crystalline film the optical properties of the liquid crystalline material change and the liquid crystal film, which is substantially transparent prior to the application of the field, becomes frosted, i.e., exhibits dynamic scattering. Thus the electro-optic cell can function as a light shutter since a large percentage (e.g. about percent of incident light would be scattered and removed from the incident light while only a small percentage, e.g., about 10 percent would be transmitted.
In the liquid crystalline electro-optic cell described in FIG. 8 the electrodes may be of any suitable transparent conductive material. Typical suitable transparent, conductive electrodes include glass or plastic substrates having substantially transparent and continuous conductive coatings of conductors such as tin, indium oxide, aluminum, chromium, tin oxide or any other suitable conductor. These substantially transparent conductive coatings are typically evaporated onto the more insulating transparent substrate. Where an opaque electrode is employed in the electro-optic cell any suitable electrode material may be used. In FIG. 8 the spacer 16, which separates the transparent electrodes and contains the liquid crystal film 17 between the electrodes is typically chemically inert, transparent, substantially insulating and has appropriate dielectric characteristics.
Materials which are suitable for use as typical insulating spacers include cellulose acetate, cellulose triacetate, cellulose acetate butyrate, polyurethane elastomers, polyethylene, polypropylene, polyesters, polystyrene, polycarbonates, polyvinylfluoride, polytetrafluoroethylene, polyethylene terephthalate, and mixtures thereof. These spacers, which also approximately define the thickness of the imaging layer or film 17 of liquid crystalline material, are preferably of a thickness in the range of about ll) mils or less. Optimum results are typically attained with spacers in the thickness range between about A mil and about 5 mils.
FIG. 9 describes a liquid crystalline electro-optic imaging cell. In this preferred embodiment the desired image is defined by the shape of an electrode and, therefore, by the shape of the corresponding electric configuration; however it will be understood by those 10 skilled in the art that both electrodes could easily be made in a matched pair to define the same desired image. When the single image electrode configuration is used the second electrode will comprise transparent substrate 14 with substantially transparent conductive 15 coating 13 upon the entire area of the inner surface of the transparent electrode. It is noted that a very thin, or substantially invisible conductor 28 is typically used in this embodiment to electrically connect the electrode in the desired image configuration to an external circuit which is similarly connected to the conductive coating of the opposite electrode. In operation this embodiment will produce an electric field only in areas where there are parallel electrodes, i.e., between the electrode in the desired image configuration and the opposite electrode, whether or not the second electrode is also in the desired image configuration. Again here, one of the electrodes may be opaque if it is desired to observe the imaged cell by reflected light rather than transmitted light.
Additionally, where the desired image is defined by the shape of one or more electrodes, an electrode may be shaped in the configuration of the background of the desired image and an imagewise electrode and such a corresponding background electrode may be coplanar 5 and insulated from one another by an open space or insulating material. Such a coplanar pair of electrodes may be operated simultaneously as a substantially fullarea electrode.
FIG. 10 describes a preferred embodiment of a liquid crystalline imaging cell embodying an x-y grid and comprising two transparent planar substrates 32 and 34 which are parallel. On the inner surface 36 of substrate 32 are arranged an array of transparent conductive strips all running in one direction. Four strips or electrodes, designated 38a, 38b, 38c, 38d, and which have parallel longitudinal axes are shown; however it will be understood that in actual practice a much larger number of electrodes may be used. On the inner surface 40 of substrate 34 are arranged an array of transparent conductive electrodes 42a, 42b, 42c, 42d having parallel longitudinal axes and being positioned substantially perpendicularly to the direction of the conductive strips 38a-38d on substrate 32. Again it will be understood that in actual practice a much larger number of electrodes may be arranged on inner surface 40 of substrate 34. The space between substrates 32 and 34 is filled with liquid crystalline which can be any of the novel compounds of the invention or mixtures thereof.
It will be understood by those skilled in the art that when two electrode strips, each being perpendicular to the other, are energized with an applied voltage, the portion of the liquid crystal cell corresponding to the intersection of the two electrodes which have been energized will become darker than the remaining area of the cell. By energizing more than one electrode strip from each set, a plurality of predetermined areas are made to appear darker.
FIG. ll describes still another preferred embodiment of a liquid crystalline electro-optic imaging cell wherein one of the electrodes comprises a photoconductor and imaging is effected by applying a uniform potential across the entire area of the electrodes and subsequently exposing the photoconductor to an imagewise pattern of activating electromagnetic radiation corresponding to a desired image configuration. Referring now to FIG. ll there is seen an electro-optic imaging cell, generally designated 50, wherein a pair of plates, generally designated 52 and 54 respectively, comprise a parallel pair of electrodes at least one of which is substantially transparent. For purposes of illustration both electrodes are shown as being transparent. Electrode 52 is made up of a photoconductive insulating material layer 53 overlying a conductive substrate which in this instance is shown as a substantially transparent conductive layer 51 deposited on a substantially transparent support member 55. Electrode 54 is shown as a substantially transparent conductive layer 56 deposited on substantially transparent substrate 57.
When it is desired to view the electro-optic cell using transmitted light it is preferred that both electrodes be substantially transparent. Of course in this instance there is required a photoconductive insulating material layer which is substantially transparent to the activating electromagnetic radiation. Typical suitable substan tially transparent photo-conductive materials include, for example, relatively thin, e.g., about 5 microns, layers of selenium. However the electro-optic imaging cell may also be viewed using reflected light thereby requiring only a single transparent electrode while the other may be opaque. In this instance one of the electrodes is preferably made up of an opaque photoconductive insulating layer deposited on an opaque substrate which may be any suitable conducting material such as a metallic layer.
The transparent electrodes are separated by spacing member 16 which contains voids which form one or more shallow cups which contain the liquid crystalline film or layer ll7. The electrodes are connected to opposite terminals of an external circuit 18. When a potential is applied to the conducting surface 51 of electrode 52 in the dark no current will flow and no field will be established across the liquid crystal film since layer 53 is insulating under these conditions. However when the imaging cell is exposed to an imagewise pattern of activating radiation, the light-struck areas of photoconductive insulating layer 53 become conductive causing current to flow and establishing a field across the liquid crystal film in the light-struck areas. The electric field causes the optical properties of the liquid crystalline material to change and the liquid crystal film, which is substantially transparent prior to the application of the field, becomes frosted, i.e., exhibits dynamic scattering thereby effecting imaging. When the imaging cell is viewed by reflected light the image will typically appear as milky-white image areas on a dark background. When the imaging cell is viewed using transmitted light the image will typically appear as dark image areas with transparent non-image or background areas.
Although the invention has be en described in detail with respect to various preferred embodiments thereof it is not intented to be limited thereto but rather it will be recognized by those skilled in the art that modifications and variations are possible which are within the spirit of the invention and the scope of the claims.
What is claimed is: 1. Liquid crystalline compositions comprising from about 55 to about 65 weight percent of and from about 35 to about 45 weight percent of 2. Liquid crystalline compositions comprising about 50 to about 70 weight percent of and about 30 to about 50 weight percent of 7' Q 3. Liquid crystalline compositions comprising about 60 to about 80 weight percent of and from about 20 to about weight percent of 4. Liquid crystalline compositions comprising from about to about 80 weight percent of and from about 20 to about 50 weight percent of 5. Liquid crystalline compositions comprising from about 50 to about 70 weight percent of and from about 30 to about 50 weight percent of applying an electric field across said liquid crystalline material, said electric field being of sufficient strength to transform said liquid crystalline material to a light-scattering state. 7. The method as defined in claim 6 wherein the liquid crystalline material is arranged between two electrodes at least one of which is substantially transparent. 8. The method of imaging a liquid crystalline material comprising,
providing a layer of a liquid crystalline material shaped in image configuration between two electrodes at least one of which is substantially transparent, said liquid crystalline material comprising a composition of claim 1, and
applying an electric field across said liquid crystalline material, said electric field being of sufficient strength to transform said liquid crystalline material to a light-scattering state whereby a visible image is formed.
9. The method of imaging a liquid crystalline material comprising,
providing a layer of a liquid crystalline material between two electrodes at least one of which is substantially transparent and at least one of which is shaped in image configuration, said liquid crystalline material comprising a composition of claim 1, and
applying an electric field across said liquid crystalline material, said electric field being of sufficient strength to transform said liquid crystalline material to a light-scattering state whereby a visible image is formed.
10. The method of imaging a liquid crystalline material comprising,
providing a layer of a liquid crystalline material between two electrodes at least one of which is substantially transparent and at least one of which includes a photoconductive surface, said liquid crystalline material comprising a composition of claim energizing said electrodes by applying a potential thereto,
exposing said photoconductive surface to an imagewise pattern of activating electromagnetic radiation causing an imagewise electric field to be applied across said liquid crystalline material, said electric field being of sufficient strength to transform said liquid crystalline material to a lightscattering state whereby a visible image is formed.
ill. The method of producing a display comprising providing a display device comprising first and second spaced plates, at least one of which is substantially transparent, a plurality of parallel electrically conductive films on one face of said first plate, a plurality of parallel electrically conductive films on one face of said second plate, the plurality of conductive films on at least one plate being substantially transparent, said two plates being positioned with said faces bearing said parallel conductive films adjacent and parallel to each other and the direction of said conductive films on one plate being perpendicular to the direction of said conductive films on the other plate, and a liquid crystalline material comprising a composition of claim 1 filling the space between said plates, and
selectively energizing at least one conductive film on each plate causing an electric field to be selectively applied across said liquid crystalline material, said electric field being of sufficient strength to selectively transform said liquid crystalline material to a light-scattering state.

Claims (10)

  1. 2. Liquid crystalline compositions comprising from about 50 to about 70 weight percent of
  2. 3. Liquid crystalline compositions comprising from about 60 to about 80 weight percent of
  3. 4. Liquid crystalline compositions comprising from about 50 to about 80 weight percent of
  4. 5. Liquid crystalline compositions comprising from about 50 to about 70 weight percent of
  5. 6. A method for transforming a liquid crystalline material from the optically transparent state to a light-scattering state comprising, providing a liquid crystalline material comprising a composition of claim 1, and applying an electric field across said liquid crystalline material, said electric field being of sufficient strength to transform said liquid crystalline material to a light-scattering state.
  6. 7. The method as defined in claim 6 wherein the liquid crystalline material is arranged between two electrodes at least one of which is substantially transparent.
  7. 8. The method of imaging a liquid crystalline material comprising, providing a layer of a liquid crystalline material shaped in image configuration between two electrodes at least one of which is substantially transparent, said liquid crystalline material comprising a composition of claim 1, and applying an electric field across said liquid crystalline material, said electric field being of sufficient strength to transform said liquid crystalline material to a light-scattering state whereby a visible image is formed.
  8. 9. The method of imaging a liquid crystalline material comprising, providing a layer of a liquid crystalline material between two electrodes at least one of which is substantially transparent and at least one of which is shaped in image configuration, said liquid crystalline material comprising a composition of claim 1, and applying an electric field across said liquid crystalline material, said electric field being of sufficient strength to transform said liquid crystalline material to a light-scattering state whereby a visible image is formed.
  9. 10. The method of imaging a liquid crystalline material comprising, providing a layer of a liquid crystalline material between two electrodes at least one of which is substantially transparent and at least one of which includes a photoconductive surface, said liquid crystalline material comprising a composition of claim 1, energizing said electrodes by applying a potential thereto, exposing said photoconductive surface to an imagewise pattern of activating electromagnetic radiation causing an imagewise electric field to be applied across said liquid crystalline material, said electric field being of sufficient strength to transform said liquid crystalline material to a light-scattering state whereby a visible image is formed.
  10. 11. The method of producing a display comprising providing a display device comprising first and second spaced plates, at least one of which is substantially transparent, a plurality of parallel electrically conductive films on one face of said first plate, a plurality of parallel electrically conductive films on one face of said second plate, the plurality of conductive films on at least one plate being substantially transparent, said two plates being positioned with said faces bearing said parallel conductive films adjacent and parallel to each other and the direction of said conductive films on one plate being perpendicular to the direction of said conductive films on the other plate, and a liquid crystalline material comprising a composition of claim 1 filling the space between said plates, and selectively energizing at least one conductive film on each plate causing an electric field to be selectively applied across said liquid crystalline material, said electric field being of sufficient strength to selectively transform said liquid crystalline material to a light-scattering state.
US00179731A 1971-09-13 1971-09-13 Nematic liquid crystalline compositions having extended mesomorphic range Expired - Lifetime US3816113A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US00179731A US3816113A (en) 1971-09-13 1971-09-13 Nematic liquid crystalline compositions having extended mesomorphic range
CA143,111A CA1003632A (en) 1971-09-13 1972-05-26 Nematic liquid crystalline compositions having extended mesomorphic range
DE2235387A DE2235387A1 (en) 1971-09-13 1972-07-19 LIQUID CRYSTALLINE COMPOSITIONS AND THEIR USE FOR THE GENERATION OF IMAGES
JP47078270A JPS4837380A (en) 1971-09-13 1972-08-04
GB4231972A GB1410221A (en) 1971-09-13 1972-09-12 Nematic liquid crystalline compounds having extended mesomorphic range
NL7212433A NL7212433A (en) 1971-09-13 1972-09-13
FR7232465A FR2248084A1 (en) 1971-09-13 1972-09-13

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00179731A US3816113A (en) 1971-09-13 1971-09-13 Nematic liquid crystalline compositions having extended mesomorphic range

Publications (1)

Publication Number Publication Date
US3816113A true US3816113A (en) 1974-06-11

Family

ID=22657746

Family Applications (1)

Application Number Title Priority Date Filing Date
US00179731A Expired - Lifetime US3816113A (en) 1971-09-13 1971-09-13 Nematic liquid crystalline compositions having extended mesomorphic range

Country Status (7)

Country Link
US (1) US3816113A (en)
JP (1) JPS4837380A (en)
CA (1) CA1003632A (en)
DE (1) DE2235387A1 (en)
FR (1) FR2248084A1 (en)
GB (1) GB1410221A (en)
NL (1) NL7212433A (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3882039A (en) * 1973-06-21 1975-05-06 Ibm Additive for liquid crystal materials
US3920576A (en) * 1973-05-07 1975-11-18 Rockwell International Corp Doping of nematic liquid crystal
US3950264A (en) * 1973-05-07 1976-04-13 Rockwell International Corporation Schiff-base liquid crystals doped to raise dynamic scattering cutoff frequency
US3956168A (en) * 1972-09-05 1976-05-11 Dainippon Ink And Chemicals, Incorporated Liquid crystal compositions
US3956167A (en) * 1973-05-17 1976-05-11 Beckman Instruments, Inc. Liquid crystal compositions and devices
US3960749A (en) * 1971-02-09 1976-06-01 International Liquid Xtal Company Liquid-crystal mixtures for use in liquid-crystal displays
US3997463A (en) * 1974-03-25 1976-12-14 Fujitsu Limited Nematic liquid crystal composition for electro-optical displays
US4038441A (en) * 1973-12-23 1977-07-26 Thomson-Csf Method of manufacturing a liquid crystal device with plane alignment
US4038761A (en) * 1976-02-17 1977-08-02 A. B. Dick Company Element and method for teaching with liquid crystals
US5786707A (en) * 1995-12-07 1998-07-28 Sharp Kabushiki Kaisha Method of detecting possible defect of liquid crystal panel

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4894689A (en) * 1972-03-13 1973-12-05
JPS5013062A (en) * 1973-06-04 1975-02-10
JPS5114183A (en) * 1974-07-26 1976-02-04 Sharp Kk EKISHOSOSEI BUTSU
JPS5282685A (en) * 1975-12-29 1977-07-11 Tokyo Ouka Kougiyou Kk Liquid crystal composites

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1170486A (en) * 1966-06-09 1969-11-12 Rca Corp Schiffs Bases and Electro-Optical Compositions and devices
US3597044A (en) * 1968-09-03 1971-08-03 Rca Corp Electro-optic light modulator
US3625591A (en) * 1969-11-10 1971-12-07 Ibm Liquid crystal display element
US3627408A (en) * 1965-06-29 1971-12-14 Westinghouse Electric Corp Electric field device
US3689525A (en) * 1970-02-28 1972-09-05 Hoechst Ag P-alkoxyphenyl esters of 4-capronyloxy benzoic acid

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS528273A (en) * 1975-07-10 1977-01-21 Toshiba Corp Vibration damping device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3627408A (en) * 1965-06-29 1971-12-14 Westinghouse Electric Corp Electric field device
GB1170486A (en) * 1966-06-09 1969-11-12 Rca Corp Schiffs Bases and Electro-Optical Compositions and devices
US3597044A (en) * 1968-09-03 1971-08-03 Rca Corp Electro-optic light modulator
US3625591A (en) * 1969-11-10 1971-12-07 Ibm Liquid crystal display element
US3689525A (en) * 1970-02-28 1972-09-05 Hoechst Ag P-alkoxyphenyl esters of 4-capronyloxy benzoic acid

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Kelker et al., A Liquid Crystalline (Nematic) Phase with a Particularly Low Solidification Point, Angew. Chem. Internat. Edit., Vol. 8, No. 11, pp. 884 885 (1969). *
Liquid Crystals Draw Intense Interest, Chemical and Engineering News, Nov. 1, 1971, pp. 20 23. *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3960749A (en) * 1971-02-09 1976-06-01 International Liquid Xtal Company Liquid-crystal mixtures for use in liquid-crystal displays
US3956168A (en) * 1972-09-05 1976-05-11 Dainippon Ink And Chemicals, Incorporated Liquid crystal compositions
US3920576A (en) * 1973-05-07 1975-11-18 Rockwell International Corp Doping of nematic liquid crystal
US3950264A (en) * 1973-05-07 1976-04-13 Rockwell International Corporation Schiff-base liquid crystals doped to raise dynamic scattering cutoff frequency
US3956167A (en) * 1973-05-17 1976-05-11 Beckman Instruments, Inc. Liquid crystal compositions and devices
US3882039A (en) * 1973-06-21 1975-05-06 Ibm Additive for liquid crystal materials
US4038441A (en) * 1973-12-23 1977-07-26 Thomson-Csf Method of manufacturing a liquid crystal device with plane alignment
US3997463A (en) * 1974-03-25 1976-12-14 Fujitsu Limited Nematic liquid crystal composition for electro-optical displays
US4038761A (en) * 1976-02-17 1977-08-02 A. B. Dick Company Element and method for teaching with liquid crystals
US5786707A (en) * 1995-12-07 1998-07-28 Sharp Kabushiki Kaisha Method of detecting possible defect of liquid crystal panel

Also Published As

Publication number Publication date
NL7212433A (en) 1973-03-15
DE2235387A1 (en) 1973-03-22
JPS4837380A (en) 1973-06-01
GB1410221A (en) 1975-10-15
FR2248084A1 (en) 1975-05-16
CA1003632A (en) 1977-01-18

Similar Documents

Publication Publication Date Title
US3816113A (en) Nematic liquid crystalline compositions having extended mesomorphic range
US3806230A (en) Liquid crystal imaging system having optical storage capabilities
US3652148A (en) Imaging system
US3756694A (en) Electric field controllable birefringence liquid crystal media and optical display devices for use thereof
US3687515A (en) Electro-optic liquid crystal system with polyamide resin additive
US4006968A (en) Liquid crystal dot color display
US4012119A (en) Direct current liquid crystal display with highly reflecting dielectric mirror
EP0166288B1 (en) Liquid crystal bistable storage device
US3947183A (en) Liquid crystal display system
US3819531A (en) Liquid crystal compositions
US3675987A (en) Liquid crystal compositions and devices
US3718382A (en) Liquid crystal imaging system in which an electrical field is created by an x-y address system
US4535327A (en) Electrically controlled display using a thick layer, non-linear element and its production process
US3779751A (en) Liquid crystalline compositions
US3540796A (en) Electro-optical compositions and devices
US3854751A (en) Method for rapidly switching a display by sequential application of orthogonal electric fields to a liquid crystal material having optical properties of the nematic mesophase
US3690745A (en) Electro-optical devices using lyotropic nematic liquid crystals
US3931041A (en) Liquid crystal compositions
US3960439A (en) Texture transformations in optically negative liquid crystals
US4219255A (en) Temperature compensated liquid crystal devices
US3707322A (en) Electrostatic latent imaging system using a cholesteric to nematic phase transition
US3842275A (en) Liquid crystal imaging system
US3716289A (en) Electro-optical display devices using smectic-nematic liquid crystal mixtures
US4005032A (en) Liquid crystalline composition having mixed cholesteric-nematic properties
USRE28806E (en) Liquid crystal compositions