OPTICAL ALIGNMENT ADJUSTING APPARATUS

PURPOSE: To obtain an optical alignment adjusting apparatus by which the alignment of an optical system can be adjusted with good accuracy without being affected by the change with time of an angle error and by an identification error by updating angle correction amount on the basis of its detection whenever an angle error amount is detected. CONSTITUTION: A laser beam from a light source 11 is projected to a scanning mirror 10 via a fixed mirror 12 and a beam splitter 13. Interference fringes are generated by an optical path difference generated at a time when the scanning mirror 10 is driven in the direction of normal line by a driving mechanism 1, and the interference fringes are inputted to a detector 14. The detector 14 computes the alignment error of an optical system on the basis of the interference fringes, a computed result is outputted to a controller 20 as a fine alignment error signal, and the controller 20 performs a closed-loop control operation so as to make the error zero. In addition, according to the driving distance of scanning mirror 10, an angle correction signal is inputted to the controller 20 from an angle error database 30, and an angle error is corrected by an open loop. In addition, whenever the fine alignment error signal is detected, the database 30 is updated by an angle-error-database update logic 40.