High-transmission electrowetting light valves

High-efficiency spatial light modulation has been demonstrated for transmissive electrowetting (FW) light valves (ELVs). The ELV structure consists of a competitive oil/water-on-dielectric EW cell fabricated on an optically transparent substrate. ELVs are configured as display devices by attaching a diffuse backlight powered by white converted InGaN light emitting diodes. The oil film contains similar to 1 wt. % nonpolar organic chromophores which absorb with near-neutral optical density across the visible light spectrum. Using the EW effect, spatial light modulation is achieved as the water layer locally displaces the oil film. The transmissivity of the cell can be modulated from similar to 5% (zero bias) to >80% (similar to 30 V). ELV switching speed depends on cell size, typically similar to 10-100 ms for 1 and 3 mm(2) cells. Additional optical enhancement can decrease the off-state ELV transmissivity to <1%. (C) 2005 American Institute of Physics.