| 摘要 |
PURPOSE:To obtain a telecentric zoom lens with the distortion corrected well, by providing five groups, a positive group, a negative group, a positive group, a negative group, and a positive group and satisfying prescribed conditions. CONSTITUTION:The telecentric zoom lens consists of the first positive group, the second negative group, the third positive group, the fourth negative group, and the fifth positive group, and the first group and the fifth group are fixed, and the second group and the fourth group are moved on the optical axis toward the first group and the third group is moved on the optical axis in the opposite direction in accordance with the magnification varying of the whole of the system from the longer focus end to the shorter focus end, and a diaphragm is fixed to the third group. These groups satisfy conditions of expressionsI-III where fW and fi are the focal length of the shorter focus end and the focal length of the i-th group, respectively. |
