Patent ID: 7547873

Claim:
Optical system for converting a substantially coherent parent light beam from a parent source into a plurality of light beams having at least reduced spatial coherence of illumination compared to said coherent parent light beam, comprising: a beam splitter for splitting said parent beam from said coherent parent light source into an array of incident beams, each incident beam being focused at a corresponding spot in a direction away from the parent light source; and a moving diffuser arrangement located at or near each said spot, and adapted for presenting a different diffuser part to each focused spot as the diffuser arrangement is moved in a path between at least two positions, the system further comprising a collimator arrangement for collimating said coherent parent light beam, wherein said beam splitter comprises a fixed grating or fixed micro-lens array comprising a plurality of micro-lens elements adapted for focusing collimated light from said collimator arrangement to a plurality of said spots, the system further comprising a relay lens for refocusing said spots to refocused spots, wherein said moving diffuser arrangement is located at or near said refocused spots, wherein a length of said path of said diffuser arrangement and at least one diffuser characteristic thereof presented to each said spot are as such to provide a plurality of differently modified wavefronts from each spot, which provide a corresponding plurality of different speckle configurations at an object illuminated via said system.