Characterization of Liquid Crystal Display Phase Modulation

The LCD is proposed as a new phase shifter with the advantage that the phase shifting is controlled digitally with no any mechanical moving and rotating elements. Phase shifting can be readily introduced by changing the coded image displayed on the LCD. Hence the LCD´s phase modulation characteristics are analyzed theoretically and experimentally. A short overview of different calibration methods is made and a new one is proposed. It relies on cross correlation technology that compare phase shifting image and standard image which grey levels is increasing linearly from the value of 0 to 255. Preliminary experimental results are also presented.