Patent ID: 6108146
Filing Date: 2000-08-22
Classification: G02B

Abstract:
A zoom assembly having a plurality of different zoom positions and focus adjustment for different object distances in each of said zoom positions, said zoom assembly comprising:a zoom lens having a plurality of lens groups defining an optical axis; anda cam barrel centered about said optical axis and having an inner peripheral surface including a plurality of identical cam grooves and no other cam grooves for moving one of said lens groups relative to another one of said lens groups, each of said cam groves including(i) a set of primary zoom sections, each one corresponding to one of said zoom positions and having a slope with respect to said optical axis, a subset of said set of said primary zoom sections having slopes of one common sign, said set of primary zoom sections also including at least one primary zoom section having a slope of opposite sign from the sign of the slopes of said subset of said set of primary zoom sections, and(ii) a set of intermediate sections corresponding to transitions from one of said plurality of zoom positions to another of said plurality of zoom positions, each of said intermediate sections having a slope with respect to said optical axis, wherein (a) said a set of intermediate sections includes a subset of intermediate sections each of which is being located between said primary zoom sections that form said subset of said primary zoom sections, and (b) said subset of intermediate sections has slopes of an opposite sign to said slopes of one, common sign.