Liquid Crystal Alignment Method for Long Lifetime Tilted-Perpendicular Light Valves

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Abstract
A new technique for tilted-perpendicular alignment (TPA) of liquid crystals on surfaces greatly improved the photostability of the photoactivated liquid crystal light valves (LCLVs) with negative dielectric anisotropy liquid crystals. The operation of surface-perpendicular aligned LCLVs provided a very dark off-state, high contrast images, and high light throughput efficiency. Alkoxy groups bonded on angle-deposited SiO2 gave controlled TPA, in which the tilt angle of LC on the treated surfaces was primarily dependent on the thickness of the shallow-angle deposited SiO2 layer. We have demonstrated improved photostability to high intensity light exposures using this TPA method in hermetically sealed cells. Projection LCLVs with very high contrast and with greater than 10,000 hours of operational stability at 2000 lumens, were obtained using this new TPA method and more stable liquid crystal mixtures.