Coating processes – Electrical product produced – Integrated circuit – printed circuit – or circuit board
Patent
1988-01-05
1990-07-03
Miller, Stanley D.
Coating processes
Electrical product produced
Integrated circuit, printed circuit, or circuit board
350347V, 350348, 350351, 4272133, 42721334, G02F 113, B01J 1302
Patent
active
049385682
ABSTRACT:
A method of forming a polymer dispersed liquid crystal (PDLC) film is disclosed which consists of forming a solution of LC dissolved in a monomer, photopolymerizing the solution to form a film having a dispersion of LC bubbles therein, establishing a correlation between the LC bubble size and selected characteristics of the film, selecting a LC bubble size corresponding to desired film characteristics, and controlling the conditions of photopolymerization to achieve said LC bubble size. The LC bubble size is controlled by means of the UV exposure intensity, exposure temperature, exposure wavelength, LC concentration and/or concentration of polymerization initiator. Correlations are noted between LC bubble size and the resulting film's threshold and operating voltages for optical transmission, contrast ratio, absolute transmissivity and electro-optical response times. Special types of films, including in situ gratings and holograms, are obtained by periodically varying the conditions of polymerization over the film to produce a corresponding periodic spatial variation in the LC bubble size; different processes used to achieve this result are noted. Films with LC bubbles in a new size regime that significantly decreases the operating voltage threshold, and with gradients in the bubble size, are also disclosed.
REFERENCES:
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patent: 3872050 (1975-03-01), Benton et al.
patent: 4435047 (1984-03-01), Fergason
patent: 4688900 (1987-08-01), Doane et al.
patent: 4728547 (1988-03-01), Vaz et al.
Nuno A. Vaz, George W. Smith and G. Paul Montgomery, Jr., "A Light Control Film Composed of Liquid Crystal Droplets Dispersed in an Epoxy Matrix", Mol. Cryst. Liq. Cryst., 1987, vol. 146, pp. 17-34.
Nuno A. Vaz et al., "A Light Control Film Composed of Liquid Crystal Droplets Dispersed in a UV-Curable Polymer", Liq. Cryst., vol. 146, 1987, pp. 1-15.
Allison Charles R.
Kohler James L.
Lackner Anna M.
Margerum John D.
Ramos Elena
Coble P. M.
Denson-Low W. K.
Duraiswamy V. D.
Gross Anita Pellman
Hughes Aircraft Company
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