Helichromic compounds and displays
AssigneeMinnesota Mining and Manufacturing Company
InventorsHarvey A. Brown, William A. Huffman
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Abstract
A composition for use in liquid crystal display devices, consisting essentially of a nematic liquid crystal material and a helichromic compound possessing both a chromophoric moiety and a helical ordering moiety. The helical ordering moiety is capable of helically ordering the mixture of liquid crystal material and helichromic compound. The helichromic compound can be utilized in conventional "guest-host" and "twist nematic" displays as well as in unique helichromic displays. When used in helichromic displays, the helichromic compounds eliminate after-image scattering and enable the display to be operated at reduced voltages.
Claims33
A composition consisting essentially of a nematic liquid crystal material and, in admixture therewith, an organic, nonionic, nonliquid-crystalline helichromic compound, said helichromic compound being soluble in said nematic liquid crystal material, and said helichromic compound being a dichroic dye and having the general formula
- Q--Z).sub.n
- wherein:
- Q is a radical selected from the group consisting of azo, azo-stilbene, benzothiazolyl polyazo, methine, azo-methine, merocyanine and methine arylidene radicals;
- Z is an organic group capable of imparting helical ordering characteristics to said mixture of nematic liquid crystal and helichromic compound;
- and
- n is an integer having a value of 1 or greater.
A composition consisting essentially of a nematic liquid crystal material and, in admixture therewith, an organic, nonionic, nonliquid-crystalline helichromic compound, said helichromic compound being soluble in said nematic liquid crystal material, and said helichromic compound being a dichroic dye and having the general formula
- Q--Z).sub.n
- wherein:
- Q is an anthraquinone radical;
- n is 1 and
- Z is an organic group capable of imparting helical ordering characteristics to said mixture of nematic liquid crystal material and helichromic compound, and Z is substituted in the 1, 4, 5, position of Q.
A composition consisting essentially of a nematic liquid crystal material and, in admixture therewith, an organic, nonionic, nonliquid-crystalline helichromic compound, said helichromic compound being soluble in said nematic liquid cyrstal material, and said helichromic compound being a dichroic dye and having the general formula
- Q--Z).sub.n
- wherein:
- Q is an anthraquinone radical;
- n is 2;
- and
- Z is an organic group capable of imparting helical ordering characteristics to said mixture of nematic liquid crystal material and helichromic compound, and Z is substituted in the 1 and 4, or 1 and 8 positions of Q.
A composition consisting essentially of a nematic liquid crystal material and, in admixture therewith, an organic, nonionic, nonliquid-crystalline helichromic compound, said helichromic compound being soluble in said nematic liquid crystal material, and said helichromic compound being a dichroic dye and having the general formula
- Q--Z).sub.n
- wherein:
- Q is an anthraquinone radical;
- Z is an organic group capable of imparting helical ordering characteristics to said mixture of nematic liquid crystal and helichromic compound, and Z includes a linking group linking it to said Q, wherein said linking group is selected from the group consisting of --CH.dbd.N--, --CH.dbd.CH--, --N.dbd.N--, --O--, --CH.sub.2).sub.p, --O--CH.sub.2).sub.p, --C--CH.sub.3).sub.2 --, ##STR96## --C.sub.6 H.sub.10 --, phenyl groups, naphthyl groups and combinations thereof, wherein p is 1, 2, 3, 4 or 5, and Z is substituted in the 1, 4, 5 or 8 position of Q or any combination thereof;
- and
- n is an integer having a value of 1 or greater.
A composition consisting essentially of a nematic liquid crystal material and, in admixture therewith, an organic, nonionic, nonliquid-crystalline, helichromic compound, said helichromic compound being soluble in said nematic liquid crystal material, and said helichromic compound being a dichroic dye having the general formula
- Q--Z).sub.n
- wherein:
- Q is an anthraquinone heterocyclic dicarboximide radical;
- n is an integer equal to 1;
- and
- Z is an organic group capable of imparting helical ordering characteristics to said mixture of nematic liquid crystal and helichromic compound, and Z is substituted on the nitrogen of said heterocyclic dicarboximide radical.
A liquid crystal display device which is responsive to the absence or presence of an electric field, said device having no auxiliary polarizers and comprising a layer of a nematic liquid crystal composition and two conductive electrodes positioned, respectively, adjacent opposing surfaces of said layer, said nematic liquid crystal composition consisting essentially of a nematic liquid crystal material and, in admixture therewith, an organic, nonionic, nonliquid-crystalline helichromic compound, said helichromic compound being soluble in said nematic liquid crystal material, said helichromic compound being a dichroic dye, said helichromic compound comprising at least one helical ordering moiety capable of imparting helical ordering characteristics to said mixture of nematic liquid crystal and helichromic compound, and said helichromic compound being present in said mixture in an amount effective to allow said mixture to substantially absorb unpolarized light incident thereon in the absence of an electric field and to substantially transmit unpolarized light incident thereon in the presence of an electric field.
The liquid crystal display device of claim 31 wherein Q is an anthraquinone radical and Z is substituted in the 1, 4, 5 or 8 position of Q, or any combination thereof.
A composition consisting essentially of a nematic liquid crystal material and, in admixture therewith, an organic, nonionic, nonliquid-crystalline helichromic compound, said helichromic compound being soluble in said nematic liquid crystal material, and said helichromic compound being a dichroic dye and having the general formula Q(Z).sub.n
- wherein:
- Q is an anthraquinone radical;
- n is 3;
- and
- Z is an organic group capable of imparting helical ordering characteristics to said mixture of nematic liquid crystal material and helichromic compound, and Z is substituted in the 1, 4 and 5 positions of Q.
A composition consisting essentially of a nematic liquid crystal material and, in admixture therewith, an organic, nonionic, nonliquid-crystalline helichromic compound, said helichromic compound being soluble in said nematic liquid crystal material, and said helichromic compound being a dichroic dye and having the general formula Q(Z).sub.n
- wherein:
- Q is an anthraquinone radical;
- n is 4;
- and
- Z is an organic group capable of imparting helical ordering characteristics to said mixture of nematic liquid crystal material andhelichromic compound, and Z is substituted in the 1, 4, 5 and 8 positions of Q.
Dependencies are inferred from the claim text.