Phase modulation device

A phase modulation device comprising:

• an image data generator configured to generate image data corresponding to a distribution of phase change amount or a distribution of phase velocity based on information data;
• a gradation data generator configured to generate gradation data corresponding to each pixel based on the image data;
• an adjustment voltage controller configured to generate an adjustment voltage based on the gradation data;
• and
• a reflective liquid crystal element to which the gradation data and the adjustment voltage are applied;
• wherein
• the reflective liquid crystal element comprises:
• a pixel region in which a plurality of pixel electrodes are arranged, and a driving voltage of a sawtooth waveform voltage pattern corresponding to the gradation data is applied;
• and
• a first adjustment electrode adjacent to the pixel region in a first direction in which the voltage pattern is repeated,
• the pixel region comprises a plurality of pixel blocks configured to modulate the phase of signal light incident on the pixel region based on the voltage pattern, and to change a wavefront of the signal light, and
• the adjustment voltage controller applies an adjustment voltage having a same voltage value as a driving voltage applied to a pixel electrode of a pixel block adjacent to the first adjustment electrode, to the first adjustment electrode.