A new method for orientation angle measurement of anisotropic medium of liquid crystal chemical and biological sensors

In this paper a new method has been used to measure the orientation angle of the nematic liquid crystal (LC) chemical and biological sensors. The presence of agents causes a change in the orientation angle of the liquid crystal molecules. Nematic liquid crystals have been used for detection of chemical and biological agents with very high sensitivity. Two orthogonal signals have been used to produce a scanning electric field in the LC film. When the resulting field vector aligns with the molecule orientation it produces low impedance (high capacitance) that can be detected and measured. A special excitation and electrode structure have been used to directly detect the orientation angle of the liquid crystal film in the XY plane.