Title :
Influence of gamma radiation on the electrooptic behavior of planar nematic liquid crystal cells
Author :
Berghmans, Francis
Author_Institution :
SCK, Belgian Nucl. Res. Center, Mol, Belgium
fDate :
4/1/1997 12:00:00 AM
Abstract :
We irradiated planar nematic liquid crystal cells with gamma-rays, to study the radiation hardness of their electrooptic characteristics. From the evolution of the electrooptic retardance curve with irradiation dose, we estimated the change of the characteristic liquid crystal material parameters with dose, using a nonlinear least square fitting algorithm. The overall gamma radiation hardness of the device is satisfactory up to doses of 456 kGy (H/sub 2/O). Two effects, however, influence the operation of liquid crystal cells as voltage tunable retarders. Radiation affects first the cohesion of the liquid crystal molecules at the boundaries and second, the conductivity of the liquid crystal cells.
Keywords :
elastic constants; electro-optical effects; gamma-ray effects; least squares approximations; liquid crystal devices; liquid crystal phase transformations; nematic liquid crystals; optical conductivity; optical elements; permittivity; tuning; 456 kGy; characteristic liquid crystal material parameters; cohesion; conductivity; electrooptic behavior; electrooptic characteristics; electrooptic retardance curve; gamma radiation; irradiation dose; liquid crystal molecules; nonlinear least square fitting algorith; planar nematic liquid crystal cells; radiation hardness; voltage tunable retarders; Active matrix liquid crystal displays; Conducting materials; Conductivity; Crystalline materials; Gamma rays; Liquid crystal devices; Liquid crystal displays; Liquid crystals; Photonic crystals; Voltage;
Journal_Title :
Photonics Technology Letters, IEEE
