Patent ID: 8102514

Claim:
A beam irradiation apparatus for scanning a target area with a laser beam, the apparatus comprising: a laser light source for emitting a laser beam; a mirror on which the laser beam emitted from the laser light source is incident; an actuator for turning the mirror in a first direction about a first axis and in a second direction about a second axis perpendicular to the first axis; a photorefractive element which is disposed in the actuator and turns in the first and second directions as the mirror turns; a servo beam source for emitting a servo beam which is used to detect a turning position of the mirror to the photorefractive element; and a photodetector for receiving the servo beam refracted by the photorefractive element and outputting a signal according to a light reception position, wherein the laser beam and the servo beam are incident on the mirror and the photorefractive element respectively so that an angle direction from an optical axis of the laser beam to be incident on the mirror to an incidence plane of the mirror and an angle direction from an optical axis of the servo beam to be incident on the photorefractive element to an incidence plane of the photorefractive element are opposite to each other.