Patent ID: 7423735
Filing Date: 2008-09-09
Classification: G01J,G01S

Abstract:
1. A beam irradiation apparatus for irradiating a beam to a target region, comprising a light source for emitting laser light, an actuator for scanning the laser light within the target region, an actuator drive unit for applying a driving signal to the actuator, a reflecting unit located at a position beyond a normal scan range of the laser light and within a limit range of scanning by the actuator, a light receiving element for receiving the laser light reflected by the reflecting unit, a comparing unit, while monitoring a detected signal outputted from the light receiving element when scanning the laser light beyond the normal scan range, for detecting a value of the driving signal applied to the actuator at the time when the detected signal being the maximum, and a controlling unit for controlling a drive of the actuator based on the value of the driving signal detected by the comparing unit, wherein the reflecting unit is located at both positions of a first position in scanning the laser light in a first direction and a second position in scanning the laser light in a second direction opposite to the first direction.