Patent ID: 7351944

Claim:
A beam irradiation device, comprising: a beam source for emitting laser beams; a lens for radiating the laser beams emitted from the beam source toward a target region; displacement means for displacing the lens at least in a direction perpendicular to an optical axis of the laser beams; scan means for driving the displacement means to cause the laser beams to perform a scan within the target region; separation means for separating a part of the laser beams that have passed through the lens; detection means for receiving the laser beams separated by the separation means and detecting a beam receiving position of the separated beams on a beam receiving face; correction means for correcting a scan position of the laser beams radiated toward the target region based on the beam receiving position detected by the detection means; and power adjusting means for setting an outgoing power of the laser beams during a period of the scan to a first level and changing the outgoing power of the laser beams to a level different from the first level when the beam receiving position detected by the detection means has reached a position corresponding to a specific position within the target region.