US Patent 7459026 Light irradiation apparatus, crystallization apparatus, crystallization method and device

A light irradiation apparatus includes a light modulation element which has a phase step having a phase difference substantially different from 180°, an illumination optical system which illuminates the light modulation element, and an image formation optical system which forms, on an irradiation surface, a light intensity distribution based on a light beam phase-modulated by the light modulation element. The illumination optical system illuminates the light modulation element with an illumination light beam inclined in a direction normal to a step line of the phase step.