Eastman-kodak Company

William T Goosey, Jr

Lee R Estelle

John N Border

Mark D Bedzyk

David Wallace Sandford

Michael Kenin

James A Schmieder

Dean A Johnson

Kazunaga Shimizu

A multiple group variable focal length lens is provided. The lens has a first lens group including a variable power lens element and is positioned in a stationary manner along an optical axis. The lens also has a second lens group moveably positioned along the optical axis. The variable power lens element can be an electrically controllable liquid lens having a surface with a variable radius of curvature created by two liquids having distinct indices of refraction with one of the liquids having an index of refraction greater than 1.60. Alternatively or additionally, at least one of the liquids used in the liquid lens can include nanoscale particles.

Zoom lens system having variable power element

A reverse telephoto zoom lens particularly suitable for use in a compact digital camera preferably has two moving lens groups in which either the first lens group has a lens component having both positive and negative power in respective radial zones of the lens or the second lens group has a lens component closer to the image plane than any other lens component and this lens component has a concave surface facing the image plane, or both. The zoom lens delivers near telecentric performance and exhibits non-reversing motion of either lens group in going between a telephoto position and a wide angle position, and vice-versa.

Reverse telephoto zoom lens

It is an object of the present invention to provide a very compact zoom assembly with a minimum number of parts. Another object of this invention is to provide a zoom assembly which does not require guide rods and utilizes with only one motor for both zooming and focusing. Briefly summarized, according to one aspect of the present invention, a zoom assembly includes a zoom lens defining an optical axis. This zoom lens is capable of operating in a plurality of different zoom positions and of focus adjustment for different object distances in each of the zoom positions. The zoom positions are (i) two extreme zoom positions (a wide angle position and a telephoto position), and (ii) a plurality of intermediate zoom positions. The zoom lens includes at least a first movable lens group and a second movable lens group. These first and second lens group are separated from one another by a variable distance. The first and second movable lens groups move (i) together, at the same speed and direction in order to focus at one of the extreme zoom positions and at an adjacent intermediate zoom position; and (ii) differentially in order to focus at another one of the extreme zoom positions.

Zoom assembly having zoom lens with plurality of lens group that move

The zoom lens according to the present invention comprises three lens units. More specifically, there is a front lens unit of positive refractive power, a middle lens unit of positive refractive power, and a rear lens unit of negative refractive power. The front lens unit has a positive lens element and a negative lens element airspaced from the positive lens element. During zooming from a wide-angle to a telephoto position, the front and the rear lens units simultaneously move the toward an object side. The middle lens unit also moves toward the object side, but by a shorter net axial distance than the distance traveled by the front and rear lens units. The 'net axial distance' refers to the axial distance between one zoom and another zoom position of a lens unit. The lens elements have sufficient optical powers, spacings and radii of curvature to provide for a large zoom ratio ZR and to maintain an overall compactness so that L.sub.v /f.sub.t &lt;0.9 and ZR =f.sub.t /f.sub.w &gt;2.5, where L.sub.v is the distance from the front vertex of the zoom lens to the film plane in the telephoto position, f.sub.t is the focal length of the zoom lens in the telephoto position, and f.sub.w is the focal length of the zoom lens in the wide-angle position.

Zoom lens

A zoom lens comprises a plurality of lens elements arranged into three zooming lens units. These zooming lens units are spaced from one another by axial distances that vary during zooming. The lens units are a negative power front lens unit, a positive power middle lens unit and a negative power rear lens unit. At least one of the lens units continually moves away from the image plane, as the zoom lens zooms from a wide angle position toward a telephoto position so that the distance from this lens unit to the image plane varies in sigmoidal relation with respect to the focal length of the zoom lens.

Compact zoom lens

The zoom lens according to the present invention comprises three lens units. More specifically, there is a front lens unit of positive refractive power consisting of a positive lens element and a negative lens element, a middle lens unit of positive refractive power, and a rear lens unit of negative refractive power. During zooming from a wide-angle to a telephoto position, the front lens unit and the rear lens unit simultaneously movable towards an object side during zooming from a wide angle to a telephoto position. The middle lens unit moves towards the object side at a relatively slower speed than that at which the front and the rear lens units are moved. The lens elements have sufficient optical powers, spacings and radii of curvature to provide for a large zoom ratio ZR and to maintain an overall compactness so that L.sub.v /f.sub.t &lt;0.9 and ZR=f.sub.t /f.sub.w &gt;2.3, where L.sub.v is the distance from the front vertex of the lens system to the film plane in the telephoto position, f.sub.t is the focal length of the lens system in the telephoto position, and f.sub.w is the focal length of the zoom lens system in the wide-angle position. At least one lens element comprising the middle or the rear lens unit has a V-number greater than 70. According to a preferred embodiment, this V-number is greater than 80. Also, according to a preferred embodiment the front and the rear lens units are integral so as to be simultaneously movable for zooming at the same speed and direction.

Compact zoom lens with a large zoom ratio

A zoom lens particularly usable in a color printer includes a first movable negative unit, a second movable positive unit and a third fixed unit. The third fixed unit has a single meniscus lens component having front and rear surfaces with a curvature within eight percent of each other. Preferably, the second movable positive unit includes a negative element having an Abbe V number between 41 and 47, which is part of a cemented triplet having Abbe V numbers higher than that of the negative element.

A compact objective lens with a diaphragm arranged behind the lens system suitable for use in very compact photographic cameras. The objective lens comprises a plurality of components arranged in a triplet or a triplet type configuration and is capable of covering at least a 55 degree field of view.

Compact objective lens system

A compact objective lens system with a diaphragm arranged in front of or preferably behind the lens system and suitable for use in compact photographic cameras. The objective lens comprises a plurality of components arranged in a triplet-type configuration that are capable of covering at least a 55 degree field of view and utilizes the locations of aperture stop, the lens bendings, and the size of lens elements, clear apertures of the lens element surfaces to enhance the lens system performance and to eliminate stray light problems.

Triplet-type lens for use in a compact photographic camera

A real image zoom finder has a zoom portion with one or more moving elements to vary the magnification of the finder. A field lens is substantially separated from suitable erecting optics to defocus any scratches or dust on the zoom lens and also to increase the compactness of the system.

Real image zoom viewfinder

A disclosed lens system is an atypical Gaussian-type lens comprised of two lens groups located at opposite sides of an aperture stop. Each of the groups is comprised of a doublet and a singlet. The doublets and singlets are located in sequential asymmetry with respect to the aperture stop. The front group has a cemented doublet as its foremost object-side lens component. This doublet consists of a lens element of negative power followed by a lens element of a positive power.

Growing community of inventors

Fairport, NY, United States of America

William T Goosey, Jr