Patent ID: 7995298

Claim:
An illumination system, comprising: at least one coherent light source, for emitting a coherent beam; a light uniforming element, disposed on a transmission path of the coherent beam; and a prism, disposed on the transmission path of the coherent beam and between the coherent light source and the light uniforming element, the prism having a light incident end and a light exit end, wherein the light incident end has at least one incident polygonal pyramid portion protruding away from the light exit end, and the prism is capable of rotating about an axis, and the axis extends from the light incident end to the light exit end, and an apex of the incident polygonal pyramid portion is located on the axis, and wherein the light exit end has at least one curved light exit surface denting towards the light incident end or protruding away from the light incident end, a chief ray of the coherent beam passes through the apex and the axis, and the rotation of the prism makes a position and an angle of the coherent beam incident on the light uniforming element change with time.