Chromatic aberration corrected gradient index lens system

Claim 1

An optical system comprised of at least one gradient index lens and an image forming homogeneous lens affixed to an end surface of said gradient index lens, said gradient indes lens being of such a length that an image is not formed at its exit surface, said system constructed and arranged to substantially correct both axial and lateral chromatic aberration of an image transmitted through said system.

Claim 17

A method of forming an optical system comprising at least one gradient index relay lens and at least one homogenous lens said method comprising: A. Choosing a relay lens of length different from an integral number of half periods of said relay lens, the difference being less than a quarter period of said lens; B. Determining by the thin-lens approximation the curvature of a homogenous lens necessary to correct said relay lens for axial chromatic aberration by the formula: ##EQU3## .sub. d, F, C=image distance in the material of the lens at each wavelength, N d , F, C=refractive index of said material at each wavelength, d=medium wavelength light, C=long wavelength light, F=short wavelength light, and c=curvature required to correct the axial chromatic aberration, cruvature being the inverse of radius of curvature; C. Determining the lateral chromatic aberration for an optical system comprised of the relay lens chosen in Step A, and a homogenous lens of curvature c, determined in Step B, D. Repeating steps A through C at least one more time for another length of the same relay lens, the length again being different from an integral number of half periods of said relay lens, with the difference being less than a quarter period of said lens; E. Plotting the lateral chromatic abberation determined by each step versus the length of relay lens at the respective steps A; F. Interpolating to determine the length of relay lens having the desired lateral chromatic aberration; G. Determining by the formula of step B the curvature of a lens of said homogenous material to substantially correct the axial chromatic aberration of said relay lens of length determined at step F; H. Providing a relay lens of the length chosen by interpolation in step F; I. Providing a lens of homogenous material with the curvature calculated in step G; and J. Affixing the uncurved surface of the lens of Step I to the surface of the relay lens of Step H.

Claim 18

A method of forming an optical system comprising at least one gradient index relay lens and at least one homogenous lens said method comprising: A. Choosing a relay lens of length different from an integral number of half periods of said relay lens, the difference being less than a quarter period of said lens; B. Determining by the thin-lens approximation the curvature of a homogenous lens necessary to correct said relay lens for axial chromatic aberration by the formula: ##EQU3## .sub. d, F, C=image distance in the material of the lens at each wavelength, N d , F, C=refractive index of said material at each wavelength, d=medium wavelength light, C=long wavelength light, F=short wavelength light, and c=curvature required to correct the axial chromatic aberration, cruvature being the inverse of radius of curvature; C. Determining the lateral chromatic aberration for an optical system comprised of the relay lens chosen in Step A, and a homogenous lens of curvature c, determined in Step B, D. Repeating steps A through C at least one more time for another length of the same relay lens, the length again being different from an integral number of half periods of said relay lens, with the difference being less than a quarter period of said lens; E. Plotting the lateral chromatic abberation determined by each step versus the length of relay lens at the respective steps A; F. Interpolating to determine the length of relay lens having the desired lateral chromatic aberration; G. Determining by the formula of step B the curvature of a lens of said homogenous material to substantially correct the axial chromatic aberration of said relay lens of length determined at step F; H. Providing a relay lens of the length chosen by interpolation in step F; I. Providing a lens of homogenous material with the curvature calculated in step G; and J. Affixing the uncurved surface of the lens of Step I to the surface of the relay lens of Step H.