Abstract：The electro-optical properties and dispersion characteristics of a liquid crystal light valve (LCLV) were investigated. A 90° twisted light valve (model TB3639) was used as a typical LCLV in the authors’ experiment. At 27 ℃ and a fixed frequency of 1 000 Hz, the transmitted light intensities (T) of the LCLV were measured as a function of wavelength (λ) at different applied voltages. From the measured T-λ curves, the dependence of contrast ratio k on the wavelength can be derived. The authors’ results showd that the TB3639 LCLV has a comparatively high contrast ratio and low dispersion within the visible region. In the range of 450-750 nm, the contrast ratio, with its value higher than 0.8, does not change much with the wavelength. Particularly the contrast ratio is higher than 0.95 with a minimum dispersion in the range of 550-670 nm.
