| 摘要 |
PURPOSE:To obtain a miniaturized and wide-angle f-theta lens with the property of image formation close to the limit of diffraction by satisfying the prescribed conditions in a lens system consisting of 3 lenses arranged in the order of positive, negative and positive lenses. CONSTITUTION:In a lens system consisting of 3 lenses arranged in the order of positive, negative and positive lenses from the incident side, the conditions represented by expressions (1) to (3) are satisfied. Where, (f) is the focal length of the whole system, f1,2 is composite forcal length between the 1st and 2nd lenses. L is the whole length of the lens system, and (r2) and (r3) are the radius of curvature of the discharging surface of the 1st lens and the incident surface of the 2nd lens, respectively. Thus, the miniaturized and wide-angle f-theta lens with the property of imge formation close to the limit of diffraction can be obtained. |
