| 摘要 |
A color tunable pixel (100) includes a cholesteric liquid crystal (110). The helical pitch of the cholesteric liquid crystal (110) is controlled by applying electrical fields (202, 302) of varying strength and/or frequency perpendicular to an initial helical axis (H) of cholesteric liquid crystal (110) in order to shift the hue of light reflected by the cholesteric liquid crystal (110). The reflectivity of the cholesteric liquid crystal (110) may be controlled by applying an electric field (402) perpendicular to the initial helical axis (H) at a frequency at which the cholesteric liquid crystal (110) exhibits a negative dielectric anisotropy. Alternatively the visible light reflectivity may be controlled by applying an electric field to shift the reflectance of the cholesteric liquid crystal (110) into the infrared portion of the spectrum, or in another embodiment by allowing the cholesteric liquid crystal (110) to revert to an ultraviolet reflected state.
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