In the typical voltage-controlled switching of liquid crystal displays and light valves the liquid crystal is the dielectric in a transparent capacitor. Voltage is applied to the capacitor and the resulting electric field on the liquid crystal reorients the molecules and therefore the liquid crystal optic axis to change the light transmission. LC MRC researchers in the Departments of Physics and Chemistry of the University of Colorado have discovered a fundamentally new mechanism for making such light valves [Materials Chemistry 9, 1257 (1999); Liquid. Crystals 27, 985 (2000); Physical Review Letters (submitted)]. The new method is based on the use of ferroelectric liquid crystals in which molecular electric dipoles adopt long-range order to give a macroscopic ferroelectric polarization tied to the molecular orientation. Electric field then couples to the polarization to reorient the molecules. While electric field coupling to the polarization to reorient the molecules in FLCs has been known for some 25 years, it is only recently that behavior in materials with very large polarization has begun to be explored. In this regime the LC MRC research has shown that the polarization becomes highly uniform and can completely screen any applied field within the liquid crystal. The result is an electro-optic cell with perfect analog response, highly desirable for making fast response gray-scale displays. The figure shows measurements of the analog response of the transmission of a polarization screened cell along with the transmission curve calculated from the LC MRC model.