Abstract This disclosure is directed to articles of manufacture, chiefly display devices, containing minute ''''naked'''' droplets or inclusions of cholesteric liquid crystal material in a substantially continuous polymeric matrix, said liquid crystal material changing color or shade of color not only upon application of an electric potential but also upon removal of the field. The image produces has a comparable outline to that of the path of the electric field. Three chromatic states are evident, the normal color (before the electric potential is applied), the color given off when the electric field is applied, and the color observed when the electric field is removed. All three chromatic states are readily discernible from one another. The polymer matrix protects the cholesteric liquid crystal droplets from aging and enhances electric field behavior because the third chromatic state (electric potential removed) has a greater longevity with the matrix-bound material versus unprotected material of identical composition but no polymeric matrix. Other advantages are also discussed.
The process of claim 1 wherein said applying of said electric field to said member is accomplished by applying 20,000 to 200, 000 volts per centimeter of thickness of said cholesteric liquid crystalline member.
Claim 2
Dependent Claim
85 words
The process of claim 1 comprising the additional steps of applying thermal energy to a portion of said cholesteric liquid crystalline member possessing said third color state in an amount sufficient to heat liquid crystals in said portion to the isotropic melt temperature of said liquid crystals thereby producing a cholesteric liquid in said portion; removing said thermal energy from said portion and allowing said heated liquid to cool to its liquid crystal state thereby producing said first color in said portion of said member.
Claim 3
Dependent Claim
36 words
The process of claim 1 wherein said droplets are individual minute, naked droplets of cholesteric liquid crystal material combined in a substantially continuous polymeric matrix having average diameters ranging from about 1 to about 30 microns.
Claim 4
Dependent Claim
42 words
The process of claim 1 wherein said cholesteric liquid crystalline member is a cholesteric liquid crystalline member containing from about 30 to about 95 weight percent cholesteric liquid crystal material, based on the total weight of said matrix and liquid crystal material.
Claim 5
Dependent Claim
28 words
The process of claim 1 wherein said liquid crystalline member is a cholesteric liquid crystalline member having an average thickness ranging from about 0.001 to about 0.05 centimeters.