Patent ID: 6762886
Filing Date: 2004-07-13
Classification: G02B

Abstract:
A 10Ã— zoom ratio wide-angle zoom lens comprising a plurality of lens sets containing a plurality of lenses with different focal lengths between an object and an image, the zoom lens comprise of:a first lens set with a positive dioptre; a second lens set with a negative dioptre, which contains: two negative-dioptre lenses; and a positive-dioptre lens, whose surface close to the object is non-spherical and has a non-spherical coefficient between âˆ’0.2 and âˆ’0.4; wherein the negative-dioptre lens close to the positive-dioptre lens is cemented to the positive-dioptre lens; a third lens set with a positive dioptre; and a fourth lens set with a positive dioptre, which contains a negative-dioptre lens that has two non-spherical surfaces with non-spherical coefficients between âˆ’1000 and âˆ’1500 and between âˆ’1000000 and âˆ’100000000, respectively; wherein a light beam from the object passes in order the first lens set, the second lens set, the third lens set, and the fourth lens set and forms the image, and the second lens set and the fourth lens set are adjusted for zooming and the fourth lens set is moved to focus.