Light modulator pixel unit and manufacturing method thereof

A light modulator pixel unit, comprising:

• a substrate;
• a bottom electrode, wherein the bottom electrode is electrically connected with a first control end of a control circuit;
• a top electrode formed on the substrate, wherein the top electrode is electrically connected with a third control end of the control circuit, the top electrode is a grating comprising at least two grating bars and grating openings between each two adjacent grating bars, and surfaces of the grating bars far away from a top surface of the bottom electrode are reflecting surfaces;
• and
• a movable electrode, located between the bottom electrode and the top electrode, wherein the movable electrode is electrically connected with a second control end of the control circuit, a surface of the movable electrode facing the top electrode is a reflecting surface, the movable electrode can move along a direction perpendicular to the reflecting surface, and an electrical insulating material is filled between the movable electrode and the top electrode and between the movable electrode and the bottom electrode,
• wherein there is a positional correspondence among the movable electrode, the top electrode, and the bottom electrode, an area of the movable electrode is less than that of the top electrode,
• wherein under control of the control circuit, the movable electrode shifts to first, second and third positions, if the movable electrode shifts to the first position, a first light incident in the light modulator pixel unit passes through the grating openings of the top electrode, and is reflected by the movable electrode and diffracted on the top electrode;
• if the movable electrode shifts to the second position, a second light incident in the light modulator pixel unit passes through the grating openings of the top electrode, and is reflected by the movable electrode and diffracted on the top electrode;
• if the movable electrode shifts to the third position, a third light incident in the light modulator pixel unit passes through the grating openings of the top electrode, and is reflected by the movable electrode and diffracted on the top electrode, and the first, second and third lights are lights in three primary colors, and
• wherein the grating bars and the grating openings have a same width ranging from about 0.1 μm to about 5 μm.