Compact seven element zoom lens with mechanical compensation

Claim 2

A zoom lens the optical portion of which consists of, in an axially aligned arrangement from the long conjugate side to the short conjugate side: a negative first lens component; a positive second lens component; a positive third lens component with unequally curved surfaces, having its more strongly curved surface toward said long conjugate, adjacent and rigidly connected to said positive second component; a negative fourth lens component; a positive meniscus fifth lens component curved toward said short conjugate; a negative sixth lens component, having a strong concave surface toward said short conjugate; and a positive seventh lens component, hAving a strong convex surface toward said long conjugate.

Claim 3

The zoom lens described in claim 1, wherein said negative first lens component is biconcave and said positive second lens component is biconvex.

Claim 4

The zoom lens described in claim 1, the mechanical portion of which includes: means for permitting said second, third, and fourth lens components to move axially from said fifth component toward said first component and to return; and compensating means for adjusting an air space between said third and fourth lens components in a predetermined manner with respect to the axial location of said second and third lens components between said first and said fifth lens components.

Claim 5

The zoom lens described in claim 1, wherein said first, second, third, and fourth lens components function as a zoom group to change the focal length of said zoom lens and said fifth, sixth, and seventh lens components function as an objective group, the lens powers of said zoom group selected so light emerging therefrom will be refracted to a focus at a finite distance behind said zoom group, and the powers and shapes of said objective group selected to correct the aberrations in said focused light entering said objective group.

Claim 6

The zoom lens described in claim 1, wherein said first, second, third, and fourth lens components function as a zoom group and wherein the last component of the zoom group has a low Abbe dispersion number.

Claim 7

The zoom lens described in claim 1, wherein the overall length of said zoom lens from its first refracting surface to its last refracting surface is less than four times its shortest focal length.

Claim 8

A zoom lens comprising in an axially aligned arrangement from its long conjugate subject side to its short conjugate film plane side: a negative first lens component, said first lens component movable axially for focusing said subject at said film plane; a first plurality of lens elements axially separated from said first lens component and axially movable so as to change its separation from said first lens component and thereby to change the focal length of said zoom lens, at least one lens of said first plurality of lens elements being axially movable with respect to the remainder of said first plurality of lens elements in a predetermined mannner so the focal plane of said zoom lens will remain at said film plane as said focal length changes, said first plurality of lens elements having a positive net refracting power greater than the negative refracting power of said first lens component; and stationary lens means for refracting onto said film plane a real image formed by the concerted action of said first lens component and said first plurality of lens elements at a conjugate point a finite distance from said second plurality of lens elements and for reducing the residual aberrations present in said real image as refracted onto said film plane, said zoom lens having an overall length from its first refracting surface to its last refracting surface less than four times its shortest focal length.

Claim 9

A zoom lens comprising in an axially aligned arrangement from its long conjugate subject side to its short conjugate film plane side: a negative first lens component, said first lens component movable axially for focusing said subject at said film plane; a first plurality of lens elements axially separated from said first lens component and axially movable so as to change its separation from said first lens component and thereby to change the focal length of said zoom lens, at least one lens of said first plurality of lens elements being axially movable with respect to the remainder of said first plurality of lens elements in a predetermined mannner so the focal plane of said zoom lens will remain at said film plane as said focal length changes, said first plurality of lens elements having a positive net refracting power greater than the negative refracting power of said first lens component; and stationary lens means for refracting onto said film plane a real image formed by the concerted action of said first lens component and said first plurality of lens elements at a conjugate point a finite distance from said second plurality of lens elements and for reducing the residual aberrations present in said real image as refracted onto said film plane, said zoom lens having an overall length from its first refracting surface to its last refracting surface less than four times its shortest focal length.

Claim 10

The zoom lens described in claim 7, wherein said first plurality of lens elements comprises from its long conjugate side to its short conjugate side: a biconvex positive lens element; a positive lens element with a strong refractive surface and a weak refractive surface, having its strong refractive surface toward said long conjugate side, separated from said biconvex positive lens element by a fixed distance; and an axially movable negative lens element, separated from said positive lens elements by an air space that can vary in a predetermined manner with respect to said separation, between said negative first lens component and said first plurality of lens elements, so the focal plane of said zoom lens will remain at said film plane as said separation changes.

Claim 11

The zoom lens described in claim 7, wherein said stationary lens means comprises from its long conjugate side to its short conjugate Side: a meniscus positive fifth lens element being concave toward said short conjugate; a negative sixth lens element, having a strong concave surface toward said short conjugate; and a positive seventh lens element, having a strong convex surface toward said long conjugate, said fifth, sixth, and seventh lens elements being axially separated from each other.

Claim 12

The zoom lens described in claim 7, wherein said first plurality of lens elements comprises from its long conjugate side to its short conjugate side: a biconvex positive lens component; a positive lens component with a strong refractive surface and a weak refractive surface, having its strong refractive surface toward said long conjugate side, separated from said biconvex positive lens component by a fixed distance; and an axially movable negative lens component, separated from said positive lens components by an air space that can vary in a predetermined manner with respect to said separation, between said negative first lens component and said first plurality of lens components, so the focal plane of said zoom lens will remain at said film plane as said separation changes.

Claim 13

The zoom lens described in claim 7, wherein said stationary lens means comprises from its long conjugate side to its short conjugate side: a meniscus positive fifth lens component being concave toward said short conjugate; a negative sixth lens component, having a strong concave surface toward said short conjugate; and a positive seventh lens component, having a strong convex surface toward said long conjugate, said fifth, sixth, and seventh lens components being axially separated from each other.

Claim 14

A mechanically compensated seven element zoom objective lens having the design parameters for a unit focal length, F, represented in the following table:

Claim 15

A mechanically compensated seven element zoom objective lens having the design parameters for a unit focal length, F, represented in the following table:

Claim 16

A mechanically compensated seven element zoom objective lens having the design parameters for a unit focal length, F, represented in the following table:

Claim 17

A mechanically compensated seven element zoom objective lens having the design parameters for a unit focal length, F, represented in the following table:

Claim 18

A zoom lens the optical portion of which consists of, in an axially aligned arrangement from its long conjugate subject side to its short conjugate film plane side: a negative first lens component, said first lens component movable axially for focusing said subject at said film plane; a first plurality of three lens components axially separated from said first lens component and axially movable so as to change its separation from said first lens component and thereby to change the focal length of said zoom lens, at least one lens component of said first plurality of lens components being axially movable with respect to the remainder of said first plurality of lens components in a predetermined manner so the focal plane of said zoom lens will remain at said film plane as said focal length changes, said first plurality of lens components having a positive net refracting power greater than the negative refracting power of said first lens component; and stationary lens means for refracting onto said film plane a real image formed by the concerted action of said first lens component and said first plurality of lens components at a conjugate point a finite distance from said second plurality of lens components and for reducing the residual aberrations present in said real image as refracted onto said film plane, said zoom lens having an overall length from its first refracting surface to its last refracting surface less than four times its shortest focal length.

Claim 19

A zoom lens the optical portion of which consists of, in an axially aligned arrangement from its long conjugate subject side to its short conjugate film plane side: a negative first lens component, said first lens component movable axially for focusing said subject at said film plane; a first plurality of three lens components axially separated from said first lens component and axially movable so as to change its separation from said first lens component and thereby to change the focal length of said zoom lens, at least one lens component of said first plurality of lens components being axially movable with respect to the remainder of said first plurality of lens components in a predetermined manner so the focal plane of said zoom lens will remain at said film plane as said focal length changes, said first plurality of lens components having a positive net refracting power greater than the negative refracting power of said first lens component; and stationary lens means for refracting onto said film plane a real image formed by the concerted action of said first lens component and said first plurality of lens components at a conjugate point a finite distance from said second plurality of lens components and for reducing the residual aberrations present in said real image as refracted onto said film plane, said zoom lens having an overall length from its first refracting surface to its last refracting surface less than four times its shortest focal length.