US 4,397,528 A · Zoom lens assembly with single operational member and means to prohibit defocussing while zooming

Abstract

In a lens assembly having a single operational member adapted to be manipulated to perform both focusing operation and zooming operation, there is provided a rotation preventing device for inhibiting rotation of the single operation member during axial movement thereof to perform zooming operation in order to prevent misalignment of a previously established focusing adjustment. The rotation preventing device includes a mechanism for establishing a frictional or spring-like force between the single operational member and a barrel member of the lens assembly in order to avoid relative rotation therebetween during zooming operation and the frictional force is initiated by a manually operable stopper member on the lens assembly.

Claims9

Dependent claims

A lens assembly having a single operational member rendered operative in two directions with respect to an optical axis to perform distance adjustment for focusing and zooming, comprising:

(a) focusing means of said lens assembly and a lens holding member holding a focusing optical lens, said focusing means controlling the axial movement of said lens holding member for focusing said focusing optical lens in response to rotation of said single operational member about said optical axis;
(b) zooming mechanical means responsive to zooming operation for performing a magnification varying function and an image shift compensating function simultaneously and arranged to avoid movement of said focusing lens group when said zooming operation is performed;
and
(c) means for prohibiting said single operational member from effecting focusing actuation while allowing it to perform zooming actuation.

1 more element

A zoom lens assembly having a single operational member capable upon rotation thereof about an optical axis of said lens assembly to effect focusing of said assembly and upon axial movement thereof to effect zooming operation of said assembly, comprising:

(a) first and second lens mounting members for holding first and second lens groups movable for zooming operation with variation of image magnification while the image shift is compensated respectively;
(b) a cylindrical member in which said first and said second lens mounting members are fitted;
(c) a third lens mounting member for holding a third lens movable for focusing;
(d) first guide means responsive to said operational member for axially moving said third lens mounting member to effect focusing;
(e) an intermediate member between said single operational member and said cylindrical member arranged to move in the same direction as said operational member simultaneously therewith upon axial movement of said operational member, said intermediate member being provided with second guide means for moving said first and said second lens mounting members responsive to axial movement of said operational member;
(f) connecting means connecting said operational member with said intermediate member, said connecting means allowing said operational member to rotate relative to said intermediate member and permitting axial movement of said operational member and said intermediate member in unison with each other;
and
(g) means for preventing rotation of said single operational member, said rotation preventing means having a member for preventing rotation of said single operational member between said single operational member and said intermediate member.

5 more elements

Dependencies are inferred from the claim text.

Zoom lens assembly with single operational member and means to prohibit defocussing while zooming

Life of this patent

Zoom lens assembly with single operational member and means to prohibit defocussing while zooming

Life of this patent

Abstract

Claims9