Document Type and Number:
Japanese Patent JPH0434126
Kind Code:
B2
Abstract:
PURPOSE:To obtain a very bright wide angle zoom lens which has about 85 deg. covering power in the wide angle side, by forming surfaces of a lens nearest to the object side and a lens nearest to the image side in a rear group of the zoom lens to aspherical surfaces and changing radiuses of curvature monotonously from centers of lenses towards peripheral parts. CONSTITUTION:In the zoom lens which consists of a front lens group having a negative refracting power and the rear lens group having a positive refracting power and varies the magnification by movement of individual groups along the optical axis, surfaces of the lens nearest to the object side and the lens nearest to the image side in the rear lens group are formed to aspherical surfaces, and radiuses of curvature of these aspherical surfaces are changed monotonously from centers of lenses to peripheral parts including signs to satisfy conditions of formulas where Rc and Re are radiuses of curvature of the center and the outermost peripheral part of the aspherical lens nearest to the object side respectively and rc and re are those of the aspherical lens nearest to the image side.
Inventors:
OKUDAIRA SADAO
Application Number:
JP19199384A
Publication Date:
June 05, 1992
Filing Date:
September 13, 1984
Export Citation:
Assignee:
ASAHI OPTICAL CO LTD
International Classes:
G02B13/18; G02B13/04; G02B15/16; G02B15/177
Next Patent: JPH0434127