Abstract: A driving method is provided for arrays of liquid crystal elements having a linear response to an applied electric field, and specifically ferroelectric liquid crystals capable of two surface-stabilized states. The presented schemes write simultaneously both states in one scan of the array, recognizing both the threshold as a critical voltage-time area and keeping this integrated averaged area equal to zero for symmetrically responding pixels. The voltage pulse trains are optimized to intrinsically assure stabilizing rms torques without applying separate holding voltages. Improvements in contrast and frame writing speed are achieved by optimizing driving parameters and scan procedures, such as scanning in loops, in combination with impedance switching.

Abstract: A new liquid crystal electro-optic device similar to the SSFLC device is described. It uses the same kind of polar chiral smectics and the same geometry as the SSFLC device (thin sample in the "book-shelf" layer arrangement) but instead of using a tilted smectic phase like the C* phase, it utilizes the above-lying, essentially non-ferroelectric A phase. The achievable optical intensity modulation is considerably lower than for the SSFLC device, but the device is about one hundred times faster. It is thus appropriate for modulator rather than for display applications. Sample fabrication is simpler and, finally, the device is insensitive to polarization compensation from external charges. The electro-optic switching at moderate applied voltages can be detected through the full range of the A phase.