The present invention relates to a liquid crystal on silicon imager. The imager includes a backplane substrate, a reflective polarization electrode array, a planar liquid crystal cell, a transparent conductive film and a transparent plate. The reflective polarization electrode array is placed onto the backplane substrate, consists of a plurality of reflective polarization electrodes, and a pattern of each of the reflective polarization electrodes is configured in a planar arrangement having regularly spaced and electrically isolated gaps in parallel to each other. The planar liquid crystal cell is placed above the reflective polarization electrode array. The transparent conductive film is placed above the planar liquid crystal cell. The transparent plate is placed on the transparent conductive film and facing incident light. Through embedding the reflective polarization electrodes, only one polarization portion could be reflected back, while the residual polarization portion is let pass but not reflected back as desired, thereby decreasing the loss in contrast ratio of the imager.