Patent ID: 8345268
Filing Date: 2013-01-01
Classification: G01B,G01S

Abstract:
1. A beam irradiation device comprising: a laser light source for emitting laser light; an actuator for causing the laser light to scan a targeted area; a servo optical system for changing a propagating direction of servo light in accordance with driving of the actuator; a photodetector for receiving the servo light and outputs a detection signal depending on a light receiving position of the servo light; a signal processing section for obtaining the light receiving position based on the detection signal; and a control section for controlling the laser light source and the actuator based on the light receiving position obtained by the signal processing section, wherein the signal processing section includes: a signal computing circuit for correcting a first digital signal derived from the detection signal outputted from the photodetector when the photodetector is irradiated by the servo light with a second digital signal derived from the error component signal outputted from the photodetector when the photodetector is not irradiated by the servo light to obtain the light receiving position.