Compact zoom lens

Abstract

The present invention is directed to a compact zoom lens that attains a reduction in outermost diameter of the lens barrel and weight and that greatly enhances a forward stroke of a first group of lenses. The compact zoom lens has a telescopic structure of a grouped-lens sliding frame, a first cam barrel, and a linearly movable barrel underlaying a fixed barrel one over another in this order, with a second cam barrel overlaying the same. Both the lens-group sliding frame and the first cam barrel are fixed in rotational direction and are engaged with each other so as to enable a relative rotation with each other along the optical axis, and the rotation of the first cam barrel is transmitted to the second cam barrel by means of the lens-group sliding frame.

Description

BRIEF DESCRIPTIONS OF THE ACCOMPANYING DRAWINGS

FIG. 1 is a sectional view illustrating a preferred embodiment of a compact zoom lens according to the present invention in a zoom-wide posture;

FIG. 2 is a sectional view illustrating the exemplary compact zoom lens in a zoom-tele posture;

FIG. 3 is an exploded view illustrating a fixed barrel of the exemplary compact zoom;

FIG. 4 is an exploded view illustrating a first cam barrel of the exemplary compact zoom;

FIG. 5 is an exploded view illustrating a 2nd-lens-group sliding frame of the exemplary compact zoom;

FIG. 6 is an exploded view illustrating a linearly movable barrel of the exemplary compact zoom;

FIG. 7 is an exploded view illustrating a second cam barrel of the exemplary compact zoom;

FIG. 8 is an exploded view illustrating a focusing cam barrel of the exemplary compact zoom lens;

FIG. 9 is an exploded view illustrating the exemplary compact zoom lens in a zoom-wide posture; and

FIG. 10 is an exploded view illustrating the exemplary compact zoom lens in a zoom-tele posture.

Claims

1. A compact zoom lens that has a multi-layer telescopic structure, comprising a fixed barrel;a grouped-lens sliding frame, a first cam barrel, and a linearly movable barrel underlaying the fixed barrel one over another in this order;a second cam barrel overlaying the fixed barrel;the grouped-lens sliding frame and the first cam barrel being fixed in rotational direction and engaged with each other so as to enable a relative rotation with each other along the optical axis; andthe rotation of the first cam barrel being transmitted to the second cam barrel by means of the grouped-lens sliding frame.

2. A compact zoom lens that has a multi-layer telescopic structure with four groups of lenses, or first to fourth lens groups, comprising a fixed barrel,a second-lens-group sliding frame, a first cam barrel, and a linearly movable barrel underlaying the fixed barrel one over another in this order,a second cam barrel overlaying the fixed barrel,the fixed barrel being formed with longitudinal guide grooves in which third-lens-group guide studs are fitted, the guide studs being implanted in and extending outward from a third-lens-group holding frame;the first cam barrel being provided with third-lens-group and fourth-lens-group guide cams, the third-lens-group guide studs being engaged with the third-lens-group guide cams while fourth-lens-group guide studs are engaged with the fourth-lens-group guide cams, and the first cam barrel having its end closer to an object formed with recesses that extend along the optical axis;the second-lens-group sliding frame having studs implanted therein and extending outward therefrom to cooperatively work with the second cam barrel, and also having second-lens-group studs implanted therein and extending inward therefrom;the linearly movable barrel being provided with apertures, longitudinal guide grooves, and second-lens-group guide cams, the third-lens-group guide studs being fitted in the apertures, the fourth-lens-group guide studs being fitted in the longitudinal guide grooves, the second-lens-group studs being engaged with the guide cams, and studs protruding outward being located ahead of the fixed barrel so as to guide a first-lens-group sliding frame; andthe second cam barrel having its outer surface provided with first-lens-group guide cams and its inner surface formed with longitudinal guide grooves, first-lens-group sliding studs implanted in the first-lens-group sliding frame being engaged with the first-lens-group guide cams while the studs implanted in the second-lens-group sliding frame to cooperatively work with the second cam barrel are fitted in the longitudinal guide grooves.