Patent ID: 11204479

Abstract:
First and second focusing lenses G2 and G3 are moved to perform focusing. The second focusing lens G3 is moved to a position, which is derived by a function f(x), relative to the position x of the first focusing lens G2. The movement of the first and second focusing lenses G2 and G3 is controlled on the basis of origins that are individually set. The origin of the first focusing lens G2 is detected by a first photo interrupter 24, and the origin of the second focusing lens G3 is detected by a second photo interrupter 34. In a case where the first and second photo interrupters 24 and 34 have mounting errors, the function f(x) is corrected on the basis of the mounting errors and the movement of the second focusing lens G3 is controlled on the basis of the corrected function F(x).