| 摘要 |
PURPOSE:To make a high resolution optical system compact by constituting the titled lens of two groups and two pieces of a positive lens and a negative lens, by emitting divergent light which is made incident from the negative lens side, as roughly parallel rays, or emitting roughly parallel rays which are made incident from the positive lens side, as a convergent light, and also, allowing said lens to satisfy specific conditions. CONSTITUTION:The titled lens is constituted of two groups and two pieces of a positive lens L1 and a negative lens L2, and divergent light which is made incident from the negative lens L2 side is emitted as roughly parallel rays, or roughly parallel rays which are made incident from the positive lens L1 side are emitted as convergent light. Also, this lens is allowed to satisfy conditions of an expression I. In the expression I, r1, r2, and r3, r4, and f, f1, and SIGMAd denote radii of curvature of the lens surface of the roughly parallel ray side and the lens surface of the divergent or convergent light side in the positive lens, respectively, radii of curvature of the lens surface of the roughly parallel ray side and the divergent or convergent light side in the negative lens, respectively, focal distances of the whole lens group and the positive lens, respectively, and the axial length of the whole lens group, respectively. Since this lens is a telephone type, even if bright lenses whose focal distances are different are opposed by placing a focus between them, the whole optical system can be made compact.
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