Miniature zoom lens

Abstract

Abstract PURPOSE:To shorten the overall length of the lens so that a prescribed variable power ratio and a photographing view angle, by specifying the lens constitution of two lens groups having prescribed refracting power and executing the variable power. CONSTITUTION:A first lens group consists of the 1-1 lens having positive refracting power, whose convex surface has turned to an object side, the 1-2 lens whose both lens surfaces are concave surfaces, and the 1-3 lens group having at least two positive refractive power, and a second lens group has two lenses of the 2-1 lens being like a meniscus and having positive refracting power, whose convex surface has turned to an image side, and the 2-2 lens having negative refracting power. Also, when each refracting power of the first lens group and the second lens group, each refracting power of the 2-1 lens and the 2-2 lens, the refracting power of the whole system at the wide angle end, a principal point interval of the first lens group and the second lens group at the wide angle end, and par-axial radiuses of curvature of the lens surfaces of the object side and the image side of the 2-2 lens are denoted as phi1, phi2, and phi2-1, phi2-2, and phiw, and 1w, and R12, R13, respectively, conditions of expressions I-VI are satisfied.

Inventors

• 👤 Yoshiaki Ito

Bibliographic Details