Abstract: Substituted phthalocyanines of a formula (I) ##STR1## wherein M is a metal atom or a metal halide or oxide, or M is 2H, one H being bonded to each of the bonding N atoms (29 and 31 positions) shown, R.sub.1 to R.sub.8 are the same or different and are independently selected from C.sub.1 to C.sub.20 alkyl, C.sub.1 -C.sub.20 alkenyl, --X--COO--X.sup.1, --X--O--Y, .alpha., and --X--COZ where X is independently selected from a chemical bond, (--CH.sub.2).sub.n where n=0-20 or (CH.sub.2).sub.n --CH.dbd.CH (--CH.sub.2).sub.b where a and b are independently selected from 0-20 and a+b is in the range 0-20, X.sup.1 is independently selected from C.sub.1 -C.sub.20 alkyl or C.sub.2 -C.sub.20 alkenyl, Y is independently selected from C.sub.1 -C.sub.20 alkyl, C.sub.2 -C.sub.20 alkenyl or H and Z is selected from OH or NR.sup.1 R.sup.11 where R.sup.1 and R.sup.11 are independently selected from H, C.sub.1 -C.sub.20 alkyl and C.sub.2 -C.sub.

Abstract: Phthalocyanine of formula (I), wherein M is a metal or is 2H, bonded at 29 and 31 positions shown, R.sub.1 to R.sub.8 are the same or different and are independently selected from C.sub.1 to C.sub.20 alkyl, C.sub.1 -C.sub.20 alkenyl, --X--COO--X.sup.1, --X--O--Y, a, and --X--COZ where X is independently selected from a chemical bond, (CH.sub.2).sub.n where n-0-20 or (CH.sub.2).sub.a CH--CH (CH.sub.2).sub.b where a and b are independently selected from 0-20 and a+b is in the range 0-20, X.sup.1 is independently selected from C.sub.1 -C.sub.20 alkyl or C.sub.2 -C.sub.20 alkenyl, Y is independently selected from C.sub.1 -C.sub.20 alkyl, C.sub.2 -C.sub.20 alkenyl or H and Z is selected from OH or NR.sup.1 R.sup.11 are independently selected from H, C.sub.1 -C.sub.20 alkyl and C.sub.2 -C.sub.20 alkenyl. These phthalocyanines may exhibit discotic liquid crystal phases, absorb infra-red radiation and make good Langmuir-Blodgett films.

Abstract: Liquid crystal compounds of formula (I) are described, where formula (I) is given as R.sub.1 --A--(X.sub.m --(B).sub.n --R.sub.2 where A is selected from nathyl, flourinated naphthyl, brominated naphthyl, B is selected from phenyl, methylated phenyl, brominated phenyl, fluorinated phenyl, thiophene, pyrimidine and pyridine, R.sub.1 and R.sub.2 are independently selected from alkyl, alkoxy, alkynyl, thioalkyl, Br, CN, SCN, NCS, perfluoroalkyl, perfluoroalkoxy and hydrogen, X is selected from C.tbd.C, COO and C.tbd.C, m is 0 or 1, n is 0 or 1 where m is 1 and n is 0 where m is 0; provided that where A is naphthyl, n is 1 and m is 0 then B is selected from methylated phenyl, brominated phenyl, thiophene, pyrimidine and pyridine; and further provided that where A is naphthyl, X is C.tbd.C, m is 1 and n is 1, then B is selected from thiophene, pyrimidine and pyridine.

Abstract: A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye characterized in that the dye comprises at least one anthraquinone compound free from water-solubilizing and ionic substituents and having the formula: ##STR1## wherein each of R and R.sup.1 independently represents an n-alkyl group having from 4 to 7 carbon atoms inclusive and wherein each of R.sup.2 and R.sup.3 is independently selected from hydrogen and alkyl groups having from 1 to 4 carbon atoms inclusive.

Abstract: A material suitable for a guest-host liquid crystal device comprises a soion of a liquid crystal material and a pleochroic dye where in the pleochroic dye comprises at least one anthrquinone compound free from water solubilizing and ionic substituents and having the formula: ##STR1## wherein Q is NH.sub.2, OH, alkyl, aryl, NO.sub.2 or halo;n is 0 to 4;each X independently is H, --SR, --NZ.sub.1 Z.sub.2 or Q;each R independently is alkyl, aryl or cycloalkyl;Z.sub.1 and Z.sub.2 are independently H, alkyl, cycloalkyl or aryl; provided that there are at least two groups X which are different --SR groups.

Abstract: A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one compound having a formula: ##STR1## wherein one of X and Y is OH and the other is NHR wherein R is H or lower alkyl; each of R.sub.1 and R.sub.2 independently represents alkyl, aryl, aralkyl, alkoxy or --NR.sub.3 R.sub.4 wherein each of R.sub.3 and R.sub.4 is independently H or lower alkyl, provided that R.sub.2 is always adjacent to an OH group.

Abstract: A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one anthraquinone compound free from water solubilizing and ionic substituents and having the formula: ##STR1## wherein P is OH or NH.sub.2 ; each group X.sup.A is independently selected from OH, NO.sub.2, SR and NZ.sub.1 Z.sub.2 provided that one group X.sup.A is SR and the other group X.sup.A is OH, NO.sub.2 or NZ.sub.1 Z.sub.2 is 1 or 2; each group Q.sub.1 is independently alkyl having from 1 to 20 carbon atoms; each group R is independently selected from alkyl having from 1 to 20 carbon atoms, aryl having up to 15 carbon atoms and cycloalkyl having from 4 to 8 carbon atoms.

Abstract: A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one compound having a formula: ##STR1## wherein: R represents a group selected from optionally substituted alkyl and optionally substituted monocyclic aryl;Q represents a group selected from halo, OH, --NO.sub.2, alkyl, aryl and --NR.sub.1 R.sub.2, wherein each of R.sub.1 and R.sub.2 independently represents a group selected from H, alkyl and aryl;x represents an integer from 1 to 4; andy represents an integer from 0 to 4;x+y being in the inclusive range 2 to 4;provided that when x+y=2, x=1 and y=1.

Abstract: A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one compound having a formula: ##STR1## wherein one of X and Y is OH and the other is NHR wherein R is H or lower alkyl; each of R.sub.1 and R.sub.2 independently represents alkyl, aryl, aralkyl, alkoxy or --NR.sub.3 R.sub.4 wherein each of R.sub.3 and R.sub.4 is independently H or lower alkyl, provided that R.sub.2 is always adjacent to an OH group.

Abstract: In accordance with the invention, a liquid crystal composition for multiplexed twisted nematic displays which exists in a nematic mesophase from at least about -20.degree. C. to 50.degree. C., comprises:(a) From two to four cyanobiphenyl compounds represented by the formula: ##STR1## wherein R is selected from the group consisting of straight chain alkyl groups having two to ten carbon atoms and the propoxy radical and wherein compounds with alkyl groups of 2 to 4 carbons range from approximately 5 to 10% by weight of the total composition and the propoxy compound ranges from approximately 5 to 15% by weight of the total composition, at least one of said compounds having an alkyl group having two to seven carbon atoms and at least one of said compounds having an alkyl group with seven to ten carbon atoms and constituting not less than approximately 25% by weight of the total composition,(b) at least one cyclohexane carboxylate ester compound represented by the formula: ##STR2## wherein R.sup.

Abstract: In accordance with the invention, a liquid crystal composition for multiplexed twisted neumatic displays which exists in a nematic mesophase from at least about -20.degree. C. to 50.degree. C.

Abstract: The present invention includes a multi-electrode structure including a counterelectrode, a display electrode in registry with the counterelectrode and finally an intermediately positioned apertured background electrode. Display material is contained between the counterelectrode and the background electrode. Depending upon the electric field conditions existing between the various electrodes, a display image may be created with a first dark-light contrast relationship relative to a background. An appropriate driving circuit is capable of changing the field relationship between the electrodes so that a reverse contrast relationship appears between a displayed image and its background.