Patent ID: 8016455

Claim:
An optical device for creating an illumination window, the optical device comprising: a plurality of radiation sources; an optical element, the optical element being arranged to create a substantially collimated radiation beam from radiation generated by the plurality of radiation sources, wherein a radiation generated by the respective plurality of radiation sources is substantially unmixed; and a first lens plate having a plurality of first sub-lenses, wherein each first sub-lens projects a part of the collimated radiation beam at the illumination window, such that projections of the each first sub-lens at least partially overlap; and a second lens plate having a plurality of second sub-lenses, wherein the plurality of the first sub-lens projects a part of the collimated radiation beam to the plurality of second sub-lenses for projecting of the part of the collimated radiation beam at the illumination window, and wherein a first lens of the first sub-lenses is tilted by a tilt angle in a first direction, and a second lens of the second sub-lenses is tilted by the tilt angle in a second direction, wherein the first direction is opposite the second direction so that the first lens and the second lens have a same tilt but in opposite directions.