PHASE CHANGE DETECTING METHOD BETWEEN THE POLARIZED LIGHT USING LIQUID CRYSTAL RETARDER

摘要

A method of detecting a phase change between polarized lights using a liquid crystal retarder is disclosed. A method of detecting a phase change between polarized lights according to an embodiment of the present invention includes a light generation unit; a first polarizer to control a polarized state of an incident light from the light generation unit; an optical waveguide to generate phase change between two polarized lights of a light passing through the first polarizer by changing a surface material; a liquid crystal retarder to control a phase delay of the polarized light outputted from the optical waveguide by an electrical signal; a second polarizer to filter the light passing through the liquid crystal retarder; and a light detection unit to convert an intensity of the light passing through the second polarizer into an electrical signal. The method of detecting a phase change between polarized lights using the polarized interference surface detection apparatus includes a first step of setting the liquid crystal retarder so that an applied voltage is increased to a predetermined value in a unit of a first time; a second step of operating the light generation unit for a second time by driving the light generation unit, and measuring a detection signal generated during the second time in the unit of the first time by the light detection unit; a third step of calculating an average value after removing a maximum value and a minimum value of the detection signal of the light detection unit; a fourth step of reverse tracking the applied voltage value of the liquid crystal retarder when the average value of the detected signal is maximum; and a fifth step of calculating an amount of a phase transition of a liquid crystal of the liquid crystal retarder by calculating and processing the applied voltage of the liquid crystal retarder and the average value of the detected signal of the light detection unit.