Control for optical system having multiple focal lengths
AssigneeEastman Kodak Company
InventorsWilliam L. Burnham, Ralph M. Lyon, Michael J. Poccia
Life of this patent
Estimating the term…
Abstract
An optical system including first and second lens groups disposed for relative movement along an optical axis and coupled together by a cam and follower mechanism for controlling such relative movement to change the focal length of the optical system. The system is characterized by a mechanism for offsetting relative movement between the lens groups along the optical axis caused by lateral movement of the lens groups essentially normal to the axis, thereby to maintain the focal length constant in the presence of the lateral movement.
Claims10
An optical system including a plurality of optical elements disposed along an optical axis, and means for moving said optical elements along the optical axis relative to each other, thereby to vary the focal length of said optical system, characterized in that:
- said moving means includes compensating means for maintaining the focal length constant upon lateral displacement of at least one of said optical elements in a direction substantially perpendicular to said optical axis, wherein said optical elements include first and second lens groups moveable along said optical axis, and first and second linkage means coupled, respectively, to said first and second lens groups for displacing said second lens group relative to said first lens group in response to movement of said first lens group along said optical axis;
- and,
- wherein said compensating means includes means for causing said first and second linkage means to move proportionally in opposite directions relative to each other to maintain the focal length of said optical system constant when at least one of said lens groups is displaced laterally in a direction substantially perpendicular to said optical axis.
An optical system including first and second lens groups disposed for relative movement along an optical axis and coupled by a cam and follower mechanism for controlling such relative movement to change the focal length of the optical system, characterized in that:
- the cam includes a face engaged by the follower, and said cam and follower mechanism includes means for offsetting relative movement between the lens groups along the optical axis caused by lateral movement of said lens groups essentially normal to said cam face, thereby to maintain the focal length constant in the presence of said lateral movement.
Dependencies are inferred from the claim text.