Three-glass photographic objective color-corrected at four wavelengths

Claim 2

An optical objective consisting of six lens elements, said six lens elements being positioned coaxially with respect to each other along an optic axis so that three of said lens elements form a first group disposed on a first side of an aperture stop of said objective, and so that another three of said lens elements form a second group disposed on a second side of said aperture stop, said six lens elements being made from only three different optical materials, said first group of lens elements being made only from a first one and a second one of said optical materials, said second group of lens elements being made only from a third one and said first one of said optical materials, said six lens elements coacting with each other so that paraxial marginal rays passing through said objective are brought to a common focus on said optic axis at four discrete wavelengths.

Claim 3

The optical objective of claim 1 wherein said first one of said three different optical materials has an index of refraction of approximately 1.62 and an Abbe number of approximately 62.19 at a base wavelength of 0.58756 micron, said second one of said three different optical materials has an index of refraction of approximately 1.77 and an Abbe number of approximately 49.62 at said base wavelength, and said third one of said three different optical materials has an index of refraction of approximately 1.55 and an Abbe number of approximately 49.52 at said base wavelength.

Claim 4

The optical objective of claim 2 wherein said first one of said three different optical materials is Hoya ADC1 optical glass, said second one of said three different optical materials is Hoya TAF1 optical glass, and said third one of said three different optical materials is Hoya SBF1 optical glass.

Claim 5

The optical objective of claim 2 having a design form optimized for a focal length of 200 millimeters at a relative aperture of f/4 over a field of view of 12° without vignetting, as follows: ______________________________________ Surface Radius Thickness No. (mm) (mm) Material ______________________________________ 1 61.267 7.813 ADCl 2 404.783 3.003 Air 3 67.358 10.034 ADCl 4 -136.878 0.220 Air 5 -135.667 7.260 TAFl 6 38.243 5.927 Air 7 Aperture Stop 20.293 Air 8 -41.821 3.107 SBFl 9 67.326 0.000 10 67.326 14.459 ADCl 11 -59.927 0.133 Air 12 -302.375 4.494 ADCl 13 -84.403 160.787 Air 14 Image plane ______________________________________ where surfaces No. 1 and No. 2 are the surfaces of a first one of said lens elements, surfaces No. 3 and No. 4 are the surfaces of a second one of said lens elements, surfaces No. 5 and No. 6 are the surfaces of a third one of said lens elements, surface No. 7 indicates an aperture stop for said objective, surfaces No. 8 and No. 9 are the surfaces of a fourth one of said lens elements, surfaces No. 10 and 11 are the surfaces of a fifth one of said lens elements, surfaces No. 12 and No. 13 are the surfaces of a sixth one of said lens elements, and surface No. 14 indicates a focal plane, said lens elements being disposed consecutively along said optic axis, each of said lens elements being rotationally symmetric about said optic axis, each of said lens elements having a radius of curvature and a thickness (as tabulated above) measured along said optic axis, spacings between adjacent surfaces being measured along said optic axis, and where ADC1, TAF1 and SBF1 are catalog designations uniquely specifying said first, second and third ones of said three different optical materials as optical glasses marked by Hoya Corporation.

Claim 6

The optical objective of claim 1, said objective having an actual focal length different from 200 millimeters at a relative aperture of f/4 over a field of view of 12°, said objective having lens elements whose surface radii of curvature and whose axial thicknesses and spacings between lens elements are obtained from a design form optimized for a focal length of 200 millimeters at said relative aperture over said field of view whose values are tabulated as follows: ______________________________________ Surface Radius Thickness No. (mm) (mm) Material ______________________________________ 1 61.267 7.813 ADCl 2 404.783 3.003 Air 3 67.358 10.034 ADCl 4 -136.787 0.220 Air 5 -135.667 7.260 TAFl 6 38.243 5.927 Air 7 Aperture Stop 20.293 Air 8 -41.821 3.107 SBFl 9 67.326 0.000 (cemented) 10 67.326 14.459 ADCl 11 -59.927 0.133 Air 12 -302.375 4.494 ADCl 13 -84.403 160.787 Air 14 Image plane ______________________________________ where surfaces No. 1 and No. 2 are the surfaces of a first one of said lens elements, surfaces No. 3 and No. 4 are the surfaces of a second one of said lens elements, surfaces No. 5 and No. 6 are the surfaces of a third one of said lens elements, surface No. 7 indicates an aperture stop for said objective, surfaces No. 8 and No. 9 are the surfaces of a fourth one of said lens elements, surfaces No. 10 and 11 are the surfaces of a fifth one of said lens elements, surfaces No. 12 and No. 13 are the surfaces of a sixth one of said lens elements, and surface No. 14 indicates a focal plane, said lens elements being disposed consecutively along said optic axis, each of said lens elements being rotationally symmetric about said optic axis, each of said lens elements having a radius of curvature and a thickness (as tabulated above) measured along said optic axis, spacings between adjacent surfaces being measured along said optic axis, and where ADC1, TAF1 and SBF1 are catalog designations uniquely specifying three different optical materials as optical glasses marked by Hoya Corporation, the radii of curvature and axial thicknesses of said lens elements and the spacings between said adjacent surfaces being determined by multiplying said values for radii and for thickness and spacings (as tabulated above) by a scaling factor, said scaling factor being the ratio of said actual focal length to said 200-millimeter focal length for which said tabulated values are optimized.

Claim 7

The optical objective of claim 2 having a design form optimized for a focal length of 200 millimeters at a relative aperture of f/5 over a field of view of 20° without vignetting, as follows: ______________________________________ Surface Radius Thickness No. (mm) (mm) Material ______________________________________ 1 68.148 8.000 ADCl 2 260.969 5.197 Air 3 56.587 10.509 ADCl 4 -224.813 0.233 Air 5 -248.416 4.263 TAFl 6 37.451 8.740 Air 7 Aperture Stop 18.323 Air 8 -33.418 3.072 SBFl 9 87.482 0.000 10 87.482 10.310 ADCl 11 -45.855 0.141 Air 12 -180.385 4.391 ADCl 13 -70.484 168.078 Air 14 Image plane ______________________________________ where surfaces No. 1 and No. 2 are the surfaces of a first one of said lens elements, surfaces No. 3 and No. 4 are the surfaces of a second one of said lens elements, surfaces No. 5 and No. 6 are the surfaces of a third one of said lens elements, surface No. 7 indicates an aperture stop for said objective, surfaces No. 8 and No. 9 are the surfaces of a fourth one of said lens elements, surfaces No. 10 and 11 are the surfaces of a fifth one of said lens elements, surfaces No. 12 and No. 13 are the surfaces of a sixth one of said lens elements, surface No. 14 indicates a focal plane, said lens elements being disposed consecutively along said optic axis, each of said lens elements being rotationally symmetric about said optic axis, each of said lens elements having a radius of curvature and a thickness (as tabulated above) measured along said optic axis, spacings between adjacent surfaces being measured along said optic axis, and where ADC1, TAF1 and SBF1 are catalog designations uniquely specifying said first, second and third ones of said three different optical materials as optical glasses marketed by Hoya Corporation.

Claim 8

The optical objective of claim 1, said objective having an actual focal length different from 200 millimeters at a relative aperture of f/5 over a field view of 20°, said objective having lens elements whose surface radii of curvature and whose axial thickness and spacings between lens elements are obtained from a design form optimized for a focal length of 200 millimeters at said relative aperture over said field of view whose values are tabulated as follows: ______________________________________ Surface Radius Thickness No. (mm) (mm) Material ______________________________________ 1 68.148 8.000 ADCl 2 260.969 5.197 Air 3 56.587 10.509 ADCl 4 -224.813 0.233 Air 5 -248.416 4.263 TAFl 6 37.451 8.740 Air 7 Aperture Stop 18.323 Air 8 -33.418 3.072 SBFl 9 87.482 0.000 (cemented) 10 87.482 10.310 ADCl 11 -45.855 0.141 Air 12 -180.385 4.391 ADCl 13 -70.484 168.078 Air 14 Image plane ______________________________________ where surfaces No. 1 and No. 2 are the surfaces of a first one of said lens elements, surfaces No. 3 and No. 4 are the surfaces of a second one of said lens elements, surfaces No. 5 and No. 6 are the surfaces of a third one of said lens elements, surface No. 7 indicates an aperture stop for said objective, surfaces No. 8 and No. 9 are the surfaces of a fourth one of said lens elements, surfaces No. 10 and 11 are the surfaces of a fifth one of said lens elements, surfaces No. 12 and No. 13 are the surfaces of a sixth one of said lens elements, and surface No. 14 indicates a focal plane, said lens elements being disposed consecutively along said optic axis, each of said lens elements being rotationally symmetric about said optic axis, each of said lens elements having a radius of curvature and a thickness (as tabulated above) measured along said optic axis, spacings between adjacent surfaces being measured along said optic axis, and where ADC1, TAF1 and SBF1 are catalog designations uniquely specifying three different optical glasses marketed by Hoya Corporation, the radii of curvature and axial thicknesses of said lens elements and the spacings between said adjacent surfaces being determined by multiplying said values for radii and for thicknesses and spacings (as tabulated above) by a scaling factor, said scaling factor being the ratio of said actual focal length to said 200-millimeter focal length for which said tabulated values are optimized.

Claim 9

The optical objective of claim 2 having a design from optimized for a focal length of 200 millimeters at a relative aperture of f/4 over a field of view of 12° without vignetting, as follows: ______________________________________ Surface Radius Thickness No. (mm) (mm) Material ______________________________________ 1 104.759 4.044 ADCl 2 221.905 2.520 Air 3 53.830 13.188 ADCl 4 -113.412 0.196 Air 5 -114.502 6.625 SBFl 6 40.019 6.625 Air 7 Aperture Stop 14.987 Air 8 -41.660 6.322 TAFl 9 168.199 0.000 10 168.199 9.136 ADCl 11 -64.833 0.178 Air 12 -953.890 7.581 ADCl 13 -63.605 172.303 Air 14 Image plane ______________________________________ where surfaces No. 1 and No. 2 are the surfaces of a first one of said lens elements, surfaces No. 3 and No. 4 are the surfaces of a second one of said lens elements, surfaces No. 5 and No. 6 are the surfaces of a third one of said lens elements, surface No. 7 indicates an aperture stop for said objective, surfaces No. 8 and No. 9 are the surfaces of a fourth one of said lens elements, surfaces No. 10 and No. 11 are the surfaces of a fifth one of said lens elements, surfaces No. 12 and No. 13 are the surfaces of a sixth one of said lens elements, and surface No. 14 indicates a focal plane, said lens elements being disposed consecutively along said optic axis, each of said lens elements being rotationally symmetric about said optic axis, each of said lens elements having a radius of curvature and a thickness (as tabulated above) measured along said optic axis, spacings between adjacent surfaces being measured along said optic axis, and where ADC1, TAF1 and SBF1 are catalog designations uniquely specifying said first, second and third ones of said three different optical materials as optical glasses marketed by Hoya Corporation.

Claim 10

The optical objective of claim 1, said objective having an actual focal length different from 200 millimeters at a relative aperture of f/4 over a field of view of 12°, said objective having lens elements whose surface radii of curvature and whose axial thicknesses and spacings between lens elements are obtained from a design form optimized for a focal length of 200 millimeters at said relative aperture over said field of view whose values are tabulated as follows: ______________________________________ Surface Radius Thickness No. (mm) (mm) Material ______________________________________ 1 104.759 4.044 ADCl 2 221.905 2.520 Air 3 53.830 13.188 ADCl 4 -113.412 0.196 Air 5 -114.502 6.625 SBFl 6 40.019 6.625 Air 7 Aperture Stop 14.987 Air 8 -41.660 6.322 TAFl 9 168.199 0.000 (cemented) 10 168.199 9.136 ADCl 11 -64.833 0.178 Air 12 -953.890 7.581 ADCl 13 -63.605 172.303 Air 14 Image plane ______________________________________ where surfaces No. 1 and No. 2 are the surfaces of a first one of said lens elements, surfaces No. 3 and No. 4 are the surfaces of a second one of said lens elements, surfaces No. 5 and No. 6 are the surfaces of a third one of said lens elements, surface No. 7 indicates an aperture stop for said objective, surfaces No. 8 and No. 9 are the surfaces of a fourth one of said lens elements, surfaces No. 10 and No. 11 are the surfaces of a fifth one of said lens elements, surfaces No. 12 and No. 13 are the surfaces of a sixth one of said lens elements, and surface No. 14 indicates a focal plane, said lens elements being disposed consecutively along said optic axis, each of said lens elements being rotationally symmetric about said optic axis, each of said lens elements having a radius of curvature and a thickness (as tabulated above) measured along said optic axis, spacings between adjacent surfaces being measured along said optic axis, and where ADC1, TAF1 and SBF1 are catalog designations uniquely specifying three different optical glasses marketed by Hoya Corporation, the radii of curvature and axial thicknesses of said lens elements and the spacings between said adjacent surfaces being determined by miltiplying said values for radii and for thicknesses and spacings (as tabulated above) by a scaling factor, said scaling factor being the ratio of said actual focal length to said 200-millimeter focal length for which said tabulated values are optimized.

Claim 11

The optical objective of claim 1 wherein said first one of said three different optical materials has an index of refraction of approximately 1.62 and an Abbe number of approximately 62.19 at a base wavelength of 0.58756 micron, said second one of said three different optical materials is selected from the group consisting of three materials those indices of refraction and Abbe numbers for the same base wavelength are approximately tabulated as follows: ______________________________________ Index of Refraction Abbe Number ______________________________________ 1.77250 49.62 1.72000 50.34 1.66960 51.66 ______________________________________ and said third one of said three different optical materials is selected from the group consisting of four materials whose indices of refraction and Abbe numbers for the same base wavelength are approximately tabulated as follows: ______________________________________ Index of Refraction Abbe Number ______________________________________ 1.55115 49.52 1.51742 52.15 1.51742 52.20 1.52341 51.49 ______________________________________

Claim 12

The optical objective of claim 10 wherein said first one of said three different optical materials is Hoya ADC1 glass, said second one of said three different optical materials is selected from the group consisting of Hoya TAF1 glass, Hoya LAC10 glass and Hoya LAC14 glass, and said third one of said three different optical materials is selected from the group consisting of Hoya SBF1 glass, Hoya CF6 glass, Schott KF6 glass and Schott KF9 glass.