Patent ID: 8169456

Claim:
A print head for irradiating light onto a plurality of locations of a photosensitive medium, comprising: a light source array including light emitting points corresponding to each of the plurality of locations of the photosensitive medium; a distributed Bragg reflector disposed adjacent a light emitting surface of the light source array; and a light focusing unit which focuses light that have passed through the distributed Bragg reflector onto the photosensitive medium, wherein the light focusing unit comprises a micro lens array disposed on one side of the distributed Bragg reflector, each micro lens of the micro lens array being arranged to correspond to a respective one of the plurality of locations of the photosensitive medium, wherein the micro lens array comprises an array of refractive lenses, the light focusing unit further comprising a micro diffractive device array formed on one side of the micro lens array in a manner such that each micro diffractive device corresponds to a respective one of the refractive lens, wherein a first side of the micro lens array adjacent the distributed Bragg reflector and a second side opposite the first side each form a substantially planar surface, wherein the second side comprises interfacing surfaces of each of the micro lenses in the micro lens array, and wherein the interfacing surfaces are adjacent to the micro diffractive device array to couple the micro lens array to the micro diffractive device.