A light modulating device includes a dispersion assembly and a lens assembly, the dispersion assembly is configured to disperse light emitting from a light source into dispersed light which at least includes collimated monochromatic light and non-collimated monochromatic light; the lens assembly includes: at least a first lens component; at least a second lens component disposed in a one-to-one correspondence with the first lens component; a first absorbing layer disposed between the first lens component and the second lens component, the first absorbing layer has an opening, a focus point of the first lens component towards the first absorbing layer coincides with a focus point of the second lens component towards the first absorbing layer, the opening is disposed at the coincident focus point of the first lens component and the second lens component.