| 摘要 |
PROBLEM TO BE SOLVED: To provide a focusing detecting device capable of performing accurate focusing by driving an objective lens to an adequate target position. SOLUTION: There are some cases where a pseudo upper side defocusing condition is detected on a detection surface DS set in the beginning even though an object image is focused on a projection surface because of the change of ambient temperature. In this case, the detection surface DS, that is, a focusing reference position is moved on an upper side in an optical axis OA direction. To put it concretely, a CCD moving device 46 is operated to arrange a CCD image pickup device 45 on a position shown by a dotted line. Because of the change of the ambient temperature, there are some cases where a pseudo lower side defocusing condition is detected on the detection surface DS set in the beginning even though the object image is focused on the projection surface. In this case, the detection surface DS, that is, the focusing reference position is moved on a lower side in the optical axis OA direction. Concretely, the device 46 is operated to arrange the device 45 on the position shown by the dotted line. |
