ZOOM LENS USING DIFFRACTION OPTICAL ELEMENT AND IMAGE PICKUP DEVICE USING THE ZOOM LENS

摘要

PROBLEM TO BE SOLVED: To excellently compensate chromatic aberration and to restrain the incident angle of luminous flux to a diffraction surface to be small from a wide angle side to a telephoto end by including a negative lens group taking the charge of the largest variable power action and a positive lens group on an image side and constituting the positive lens group of one diffraction optical element. ;SOLUTION: This lens is equipped with a 1st group G1 consisting of one positive meniscus lens whose convex surface faces to an object side, a 2nd group G2 consisting of a negative meniscus lens and the positive meniscus lens whose convex surfaces face to the object side and having the largest variable power action, a diaphragm S, a 3rd group G3 consisting of the diffraction optical element(DOE) provided with a diffraction surface r₁₀ on the surface of the positive meniscus lens whose convex surface faces to the object side on the image side, and a 4th group G4 consisting of one double-positive lens. Then, from the wide angle end to the telephoto end, the 1st group G1 and the diaphragm S are fixed, the 2nd group G2 is moved to the image side, and the 3rd and the 4th groups G3 and G4 are moved to the object side. An aspherical surface is used as the surface of the 2nd group G2 nearest to the image side and the surface of the 4th group G4 on the object side.;COPYRIGHT: (C)1999,JPO