| 摘要 |
PURPOSE:To easily and securely detect the position of an object of transmission by displacing a light beam irradiation position within a specific range, detecting the photodetection area of a light beam reflected by a corner cube reflector, and detecting the position of the center of gravity of the photodetection area. CONSTITUTION:A semiconductor laser 2 emits the light beam having a specific plane of polarization and the object of transmission is irradiated with a light beam LA1 modulated with a desired information signal to send the information signal to the object of transmission. In this case, the light beam irradiation position is displaced within the specific range and after the photodetection area of the light beam LA3 reflected by the corner cube reflector 30 is detected, the position of the center of gravity of the photodetection area is detected to correctly judge the position of the object of transmission. For the purpose, the object of transmission is irradiated with the light beam LA1 on the basis of the gravity center position and then the position of the object of transmission is easily detected to correct the light beam irradiation position. |
