Patent ID: 8610993

Claim:
A light control device comprising: a light source that outputs light; a phase modulating spatial light modulator that is capable of phase modulation in each of a plurality of two-dimensionally arrayed pixels in a range of 4π, is input with light output from the light source, presents a phase pattern to modulate the phase of light in each of the pixels, and outputs light after being phase-modulated by this phase pattern; and a control unit that causes the spatial light modulator to present a phase pattern produced by superimposing a blazed grating pattern for light diffraction with a phase modulation range of 2π or less and a phase pattern having a predetermined phase modulation distribution with a phase modulation range of 2π or less, and adjusts the light diffraction efficiency in the spatial light modulator by adjusting the blazed grating pattern, wherein the phase modulation range of the phase pattern produced by superimposing the blazed grating pattern and the phase pattern having a predetermined phase modulation distribution is 2π or more; and phase folding is not performed for the phase pattern produced by superimposing the blazed grating pattern and the phase pattern having a predetermined phase modulation distribution.