Cholesteric liquid crystalline phase material-dye composition and venapuncture method employing the composition

Claim 1

A composition of matter having thermal color responsive characteristics and adapted for exhibiting improved color contrast which comprises an enantiotropic cholesteric liquid crystalline phase material, and at least two oil-soluble dyes dissolved in said material in a total dye concentration of 0.01-1% by weight of the composition, each of said dyes reflecting light of a different wave length in the range of 400 to 700 nanometers, and said dyes together absorbing light of substantially all wave lengths within said range.

Claim 13

A method of effecting vanapuncture in the human body which comprises: a. in any order, (1) cooling the skin over a venous area of the body, and (2) applying directly on the skin over said area a layer about 100 to 300 microns thick of a composition having thermal color responsive characteristics, said layer exhibiting improved color contrast and high color intensity, said composition comprising an enantiotropic cholesteric liquid crystalline phase material exhibiting a mesophase color change at a temperature reached by the skin upon rewarming due to venous blood flow, and at least two oil-soluble dyes dissolved in said material in a total dye concentration of 0.01-1% by weight of the composition, each of said dyes reflecting light of a different wave length in the range of 400 to 700 nanometers, and said dyes together absorbing light of substantially all wave lengths within said range; b. allowing the skin over said area to rewarm due to venous blood flow, until said material exhibits a mesophase color change to thereby delineate a vein therebeneath; and c. directing an instrument for venapuncture to a site in said area indicated by said delineation to constitute the location of a vein.

Claim 14

A method of effecting vanapuncture in the human body which comprises: a. in any order, (1) cooling the skin over a venous area of the body, and (2) applying directly on the skin over said area a layer about 100 to 300 microns thick of a composition having thermal color responsive characteristics, said layer exhibiting improved color contrast and high color intensity, said composition comprising an enantiotropic cholesteric liquid crystalline phase material exhibiting a mesophase color change at a temperature reached by the skin upon rewarming due to venous blood flow, and at least two oil-soluble dyes dissolved in said material in a total dye concentration of 0.01-1% by weight of the composition, each of said dyes reflecting light of a different wave length in the range of 400 to 700 nanometers, and said dyes together absorbing light of substantially all wave lengths within said range; b. allowing the skin over said area to rewarm due to venous blood flow, until said material exhibits a mesophase color change to thereby delineate a vein therebeneath; and c. directing an instrument for venapuncture to a site in said area indicated by said delineation to constitute the location of a vein.

Claim 20

A method of effecting venapuncture in the human body which comprises: a. in any order, (1) cooling the skin over a venous area of the body, and (2) applying directly on the skin over said area a layer about 100 to 300 microns thick of a composition having thermal color responsive characteristics and being in the form of an organic solvent-free paste, said layer exhibiting improved color contrast and high color intensity, said composition comprising an enantiotropic cholesteric liquid crystalline phase material having a mesophase temperature range within the range of 28°-38° C and exhibiting a mesophase color change at a temperature reached by the skin upon rewarming due to venous blood flow, the skin temperature following said cooling being below said mesophase temperature range, and at least two oil-soluble dyes dissolved in said material in a total dye concentration of 0.01-1% by weight of the composition, each of said dyes reflecting light of a different wave length in the range of 400 to 700 nanometers and being selected from the group consisting of dyes having the Color Index designations: Solvent Yellow 5, Solvent Yellow 30, Solvent Yellow 33, Solvent Orange 2, Solvent Orange 17, Solvent Red 23, Solvent Red 27, Solvent Red 49, Solvent Green 3, Solvent Green 7, Solvent Violet 13, and Solvent Violet 17, and said dyes together absorbing light of substantially all wave lengths within said range and exhibiting a violet, brown, or brown-black color at room temperature; b. allowing the skin over said area to rewarm due to venous blood flow, until said material exhibits a mesophase color change to thereby delineate a vein therebeneath; and c. directing an instrument for venapuncture to a site in said area indicated by said delineation to constitute the location of a vein.

Claim 21

A method of effecting venapuncture in the human body which comprises: a. in any order, (1) cooling the skin over a venous area of the body, and (2) applying directly on the skin over said area a layer about 100 to 300 microns thick of a composition having thermal color responsive characteristics and being in the form of an organic solvent-free paste, said layer exhibiting improved color contrast and high color intensity, said composition comprising an enantiotropic cholesteric liquid crystalline phase material having a mesophase temperature range within the range of 28°-38° C and exhibiting a mesophase color change at a temperature reached by the skin upon rewarming due to venous blood flow, the skin temperature following said cooling being below said mesophase temperature range, and at least two oil-soluble dyes dissolved in said material in a total dye concentration of 0.01-1% by weight of the composition, each of said dyes reflecting light of a different wave length in the range of 400 to 700 nanometers and being selected from the group consisting of dyes having the Color Index designations: Solvent Yellow 5, Solvent Yellow 30, Solvent Yellow 33, Solvent Orange 2, Solvent Orange 17, Solvent Red 23, Solvent Red 27, Solvent Red 49, Solvent Green 3, Solvent Green 7, Solvent Violet 13, and Solvent Violet 17, and said dyes together absorbing light of substantially all wave lengths within said range and exhibiting a violet, brown, or brown-black color at room temperature; b. allowing the skin over said area to rewarm due to venous blood flow, until said material exhibits a mesophase color change to thereby delineate a vein therebeneath; and c. directing an instrument for venapuncture to a site in said area indicated by said delineation to constitute the location of a vein.