Patent ID: 7525738

Claim:
A lens system in an imaging device, comprising, in sequence from an object side to an image side: a first lens group having negative refractive power, and comprising a plurality of lenses, among which one lens is made of resin material and has an Abbe number greater than 55; a second lens group having positive refractive power, and comprising first and second lenses cemented together to form a composite lens having an object side and an image side on both of which aspheric resin layers are formed, ratio between radius of curvature of an object side of the aspheric resin layer on the image side of the composite lens and radius of curvature of the image side of the said aspheric resin layer being between 0.8 and 1.1; and a third lens group having positive refractive power, and comprising a positive lens made of resin material with Abbe number greater than 55; wherein in zooming, the first lens group remains stationary, and when performing from a wide-angle end to a telephoto end, the second lens group moves away from an image plane, while the third lens group moves toward the image plane, whereby distance between the first and second lens groups is decreased while distance between the second and third lens groups is increased.