Patent ID: 7187399

Claim:
An exposure head that relatively moves along a scanning direction with respect to an exposure plane and is for two-dimensionally exposing the exposure plane with a bundle of light beams arranged along a row direction orthogonal to the scanning direction, the exposure head comprising: a spatial light modulator where plural pixel portions whose light modulation states respectively change in correspondence to control signals are one-dimensionally or two-dimensionally arranged, which spatial light modulator divides light beams made incident thereon from a light source portion into plural pixel beams using the plural pixel portions, and selectively modulates the respective plural pixel beams into one of an exposure state and a non-exposure state; an imaging lens system disposed downstream of the spatial light modulator along the traveling direction of the pixel beams; a first micro-focusing element array disposed downstream of the imaging lens system, where plural first micro-focusing elements are arranged so as to correspond to the plural pixel portions of the spatial light modulator; an aperture array that is disposed in the vicinity of a rear-side focal plane of the first micro-focusing elements at which the first micro-focusing elements form Fraunhofer diffraction images of the pixels beams modulated to the exposure state by the spatial light modulator, and in which aperture array plural apertures that respectively correspond to the plural first micro-focusing elements are arranged, and which aperture array allows only main portions of the Fraunhofer diffraction images to be transmitted through the apertures; and a second micro-focusing element array disposed downstream of the aperture array, that includes plural second micro-focusing elements arranged so as to correspond to the plural apertures and which array forms, on the exposure plane, real images of the pixel beams respectively transmitted through the plural apertures by using the plural second micro-focusing elements.