Zoom lens
AssigneesOptical Logic Inc., Kantatsu Co., Ltd.
InventorsYoji KUBOTA, Kenichi KUBOTA, Hitoshi HIRANO
Life of this patent
Estimating the term…
Abstract
A zoom lens includes a first lens group G1 that is negative, a second lens group G2 that is negative, and a third lens group G3 that is positive. The first lens group G1 includes a first lens L1 that is negative and a prism P, and the second lens group G2 includes a second lens L2 that is positive and a third lens L3 that is negative. The third lens group G3 includes a stop ST, a fourth lens L4 that is positive, and a fifth lens L5 that is negative. According to this configuration, upon changing magnification from a wide-angle end to a telephoto end, the first lens group G1 is secured, the second lens group G2 first moves to the image plane side and then moves to the object side, and the third lens group G3 linearly moves to the object side.
Claims6
A zoom lens comprising:
- a first lens group having negative refractive power;
- a second lens group having negative refractive power;
- and
- a third lens group having positive refractive power, arranged in this order from an object side to an image plane side,
- wherein said first lens group includes a first lens having negative refractive power so that a curvature radius of a surface thereof on the image plane side is positive, and a light path changing member for changing a traveling direction of an incident light,
- said second lens group includes a second lens having positive refractive power so that a curvature radius of a surface thereof on the object side is positive, and a third lens having negative refractive power so that a curvature radius of a surface thereof on the object side is negative,
- said third lens group includes a fourth lens having positive refractive power and a fifth lens having negative refractive power so that a curvature radius of a surface thereof on the object side is positive, and
- said first lens group is secured, said second lens group first moves to the image plane side and then moves to the object side, and said third lens group linearly moves to the object side when a magnification of the zoom lens is changed from an wide-angle end to a telephoto end.
Dependencies are inferred from the claim text.