Patent ID: 6936193

Claim:
A film suitable for use as a light-modulating unit of suspended particle device (SPD) light valve, said film comprising a matrix polymer material and having droplets of a liquid light valve suspension comprising a plurality of particles dispersed in a liquid suspending medium distributed within the matrix, wherein said liquid suspending medium (a) is substantially immiscible with the matrix polymer material, (b) has a boiling point at atmospheric pressure greater than about 100° C., (c) has an electrical resistivity of at least about 0.8×10 6 ohms per square, and (d) has an index of refraction at 25° C. which differs from an index of refraction of the matrix polymer at substantially the same temperature by no more than about 0.002, and wherein said suspending medium comprises at least one liquid component selected from the group consisting of methyl pyrrolidinone, ethyl pyrrolidinone, dimethyl malonate, diethyl malonate, dimethyl succinate, di(propylene glycol)methyl ether, dimethyl phthalate, butyl phthalyl butyl glycolate, ethyl lactate, propylene carbonate, dimethyl tetrafluorosuccinate, tetra(ethylene glycol)dimethyl ether, tri(ethylene glycol) dimethyl ether, di(ethylene glycol)dimethyl ether, ethylene glycol phenyl ether, epoxidized linseed oil, epoxidized soy oil, diethylisophthalate, a silicone copolyol-based laurate ester, a silicone copolyol copolymer, a silicone copolyol ester, a silicone copolyol-based isostearate ester, a silicone copolyol-based pelargonate ester, dimethyl octofluoroadipate, and mixtures thereof.