Objective comprising aspherical surfaces, whose focal length is variable over a wide range

Claim 2

A variable focal length objective lens for focusing an image of an object at a stationary image plane, said lens having an aperture number between 1.5 and 2 and comprising components, each having at least one lens element, arranged along an optical axis, including: (a) first and second stationary components arranged in order between an object field and the stationary image plane, said components having positive focal lengths; and (b) first and second movable components each comprising a single element, arranged in order between the first and second stationary components, said first movable component having a negative focal length and said second movable component having a positive focal length, at least one of said single elements having an aspherical surface, said movable components being axially displacable relative to each other to effect a focal length variation of at least 5 to 1.

Claim 3

A variable focal length objective lens for focusing an image of an object at a stationary image plane, said lens having an aperture number between 1.5 and 2 and comprising components, each having at least one lens element arranged along an optical axis, including: (a) first and second stationary components arranged in order between an object field and the stationary image plane, said first stationary component having a focal length F 1 ; and (b) first, second and third movable components, each comprising a single element, arranged in order between the first and second stationary components and having focal lengths F 2 , F 3 and F 4 , respectively, where F 2 /F 1 and F 3 /F 1 are negative and F 4 /F 1 is positive, at least one of said single elements having an aspherical surface, said movable components being axially displaceable relative to each other to effect a focal length variation of at least 5 to 1.

Claim 4

A variable focal length objective lens for focusing an image of an object at a stationary image plane, said lens having an aperture number between 1.5 and 2 and comprising components, each having at least one lens element arranged along an optical axis, including: (a) first and second stationary components arranged in order between an object field and the stationary image plane, said first stationary component having a focal length F 1 ; and (b) first, second and third movable components, each comprising a single element, arranged in order between the first and second stationary components and having focal lengths F 2 , F 3 and F 4 , respectively, where F 2 /F 1 and F 3 /F 1 are negative and F 4 /F 1 is positive, at least one of said single elements having an aspherical surface, said movable components being axially displaceable relative to each other to effect a focal length variation of at least 5 to 1.

Claim 5

A variable focal length objective lens for focusing an image of an object at a stationary image plane, said lens having a free image distance greater than 22 mm and comprising components, each having at least one lens element arranged along an optical axis, including: (a) first and second stationary components arranged in order between an object field and the stationary image plane, said components having positive focal lengths; and (b) first and second movable components, each comprising a single element, arranged in order between the first and second stationary components, said first movable component having a negative focal length and said second movable component having a positive focal length, at least one of said single elements having an aspherical surface, said movable components being axially displacable relative to each other to effect a focal length variation of at least 5 to 1.

Claim 6

A variable focal length objective lens for focusing an image of an object at a stationary image plane, said lens having a free image distance greater than 22 mm and comprising components, each having at least one lens element arranged along an optical axis, including: (a) first and second stationary components arranged in order between an object field and the stationary image plane, said components having positive focal lengths; and (b) first and second movable components, each comprising a single element, arranged in order between the first and second stationary components, said first movable component having a negative focal length and said second movable component having a positive focal length, at least one of said single elements having an aspherical surface, said movable components being axially displacable relative to each other to effect a focal length variation of at least 5 to 1.

Claim 7

A variable focal length objective lens for focusing an image of an object at a stationary image plane, said lens having a free image distance greater than 22 mm and comprising components, each having at least one lens element, arranged along an optical axis, including: (a) first and second stationary components arranged in order between an object field and the stationary image plane, said first stationary component having a focal length F 1 ; and (b) first, second and third movable components, each comprising a single element, arranged in order between the first and second stationary components and having focal lengths F 2 , F 3 and F 4 , respectively, where F 2 /F 1 and F 3 /F 1 are negative and F 4 /F 1 is positive, at least one of said single elements having an aspherical surface, said movable components being axially displaceable relative to each other to effect a focal length variation of at least 5 to 1.

Claim 8

A variable focal length objective lens for focusing an image of an object at a stationary image plane, said lens having a free image distance greater than 22 mm and comprising components, each having at least one lens element, arranged along an optical axis, including: (a) first and second stationary components arranged in order between an object field and the stationary image plane, said first stationary component having a focal length F 1 ; and (b) first, second and third movable components, each comprising a single element, arranged in order between the first and second stationary components and having focal lengths F 2 , F 3 and F 4 , respectively, where F 2 /F 1 and F 3 /F 1 are negative and F 4 /F 1 is positive, at least one of said single elements having an aspherical surface, said movable components being axially displaceable relative to each other to effect a focal length variation of at least 5 to 1.

Claim 9

A variable focal length objective lens as in claim 3 or 4, characterized in that the aperture is F/1.8, and having the physical characteristics specified in the following Tables I and II, where the dioptric surfaces of the objective are designated 1 to 17 from the object field to the image field, where E designates axial distances between designated surfaces for a focal length F=7.97 mm, where n designates the refractive index, where ν designates the Abbe dispersion number, and where the symbols C, λ, ε i represent coefficients in the following equation describing the cross sections of the aspherical dioptric surfaces 7, 8, 10 in a plane which passes through the optical axis ##EQU3## the abscissa x being measured from the apex of the dioptric surface along the optical axis, and the ordinate perpendicularly to said axis: TABLE I ______________________________________ Dioptric E R surface (mm) (mm) n ν ______________________________________ 1 111.111 2.962 1.704485 29.88 2 43.910 11.099 1.622857 60.11 3 876.647 0.050 1.000000 4 53.395 6.503 1.622857 60.11 5 129.296 2.936 1.000000 6 -17.988 1.113 1.591288 60.94 7 8.261 1.896 1.000000 8 35.029 3.452 1.550192 53.17 9 -39.013 59.841 1.000000 10 25.384 2.982 1.654317 38.91 11 -62.563 7.889 1.000000 12 309.102 3.025 1.622857 60.11 13 -18.230 0.050 1.000000 14 -68.031 0.802 1.812529 25.30 15 13.760 1.032 1.000000 16 25.702 2.625 1.622857 60.11 17 -30.820 0.000 1.000000 ______________________________________ Focal-length variation F: 7.95 to 63.50 Image distance: 22.14 mm Objective length: 108.25 mm TABLE II ______________________________________ Dioptric surface 7 8 10 ______________________________________ C 1.21048 10.sup.-1 2.85479 10.sup.-2 3.93954 10.sup.-2 λ -1.42139 -1.07632 -2.90598 ε.sub.2 -1.68578 10.sup.-4 -1.89696 10.sup.-5 -2.27969 10.sup.-5 ε.sub.3 2.73671 10.sup.-6 3.04327 10.sup.-7 -1.91999 10.sup.-7 ε.sub.4 -6.58215 10.sup.-8 -5.01920 10.sup.-9 1.14049 10.sup.-9 ε.sub.5 5.46590 10.sup.-10 2.90044 10.sup.-11 -1.55755 10.sup.-11 ______________________________________

Claim 10

A variable focal length objective lens as in claim 3 or 4, characterized in that the aperture is F/ 1.8, and having the physical characteristics specified in the following Tables V and VI, where the dioptric surfaces of the objective are designated 1 to 11 from the object field to the image field, where E designates the axial distance between designated surfaces for the focal length F=17 mm, where n designates the refractive index, where ν designates the Abbe dispersion number, and where the symbols, C, λ, ε i represent coefficients in the following equation describing the cross sections of the aspherical dioptric surfaces 2, 3, 5, 8, 9 in a plane which passes through the optical axis ##EQU4## the abscissa x being measured from the apex of the dioptric surface along the optical axis and the ordinate perpendicularly to said axis: TABLE V ______________________________________ Dioptric E R surface (mm) (mm) n ν ______________________________________ 1 62.852 6.300 1.677623 32.08 2 17.997 31.400 1.000000 3 31.080 10.395 1.622857 60.11 4 403.858 1.100 1.000000 5 50.717 9.458 1.622857 60.11 6 -279.735 1.750 1.000000 7 -33.369 0.866 1.622857 60.11 8 21.567 52.400 1.000000 9 18.083 5.662 1.622857 60.11 10 -10.914 0.396 1.812529 25.30 11 -21.976 0.000 1.000000 ______________________________________ Focal-length variation F: 7.0 to 56.0 mm. Image distance: 22.19 mm. Length 2: 120.42 mm TABLE VI __________________________________________________________________________ Dioptric surface 2 3 5 8 9 __________________________________________________________________________ C 5.55650 10.sup.-2 3.21750 10.sup.-2 1.97173 10.sup.-2 4.63672 10.sup.-2 5.53002 10.sup.-2 λ -6.96979 10.sup.-1 -1.13548 -9.75088 10.sup.-1 -1.52017 10.sup.-1 -7.10788 10.sup.-1 ε.sub.2 -5.38859 10.sup.-6 -9.88210 10.sup.-7 1.30489 10.sup.-6 -1.14601 10.sup.-5 -1.99591 10.sup.-5 ε.sub.3 -9.03598 10.sup.-9 -1.03273 10.sup.-9 -3.89438 10.sup.-10 9.99829 10.sup.-8 2.71237 10.sup.-8 ε.sub.4 3.92014 10.sup.-12 1.46391 10.sup.-12 -6.31723 10.sup.-13 -8.14572 10.sup.-10 1.99891 10.sup.-9 ε.sub.5 0.00000 0.00000 0.00000 0.00000 0.00000 __________________________________________________________________________

Claim 11

A variable focal length objective lens as in claim 3 or 4, characterized in that the aperture is equal to F/ 1.8, and having the physical characteristics specified in the following Tables VII and VIII, where the dioptric surfaces of the objective are designated 1 to 16 from the object field to the image field, where E designates the axial distance between designated surfaces for the focal length F=15.00 mm, where n designates the refractive index, where ν designates the Abbe dispersion number, and where the symbols C, λ, ε i represent coefficients in the following equation describing the cross sections of the aspherical dioptric surfaces 4, 7, 12, 16 in a plane passing through the optical axis ##EQU5## the abscissa x being measured from the apex of the dioptric surface along the optical axis and the ordinate perpendicularly to said axis: TABLE VII ______________________________________ Dioptric E R surface (mm) (mm) n ν ______________________________________ 1 52.985 2.499 1.734359 28.17 2 31.271 13.466 1.622857 60.11 3 180.118 0.050 1.000000 4 60.986 5.533 1.622857 60.11 5 184.952 19.067 1.000000 6 -318.707 0.940 1.591288 60.94 7 11.422 7.021 1.000000 8 -10.909 0.636 1.591288 60.94 9 -136.669 3.649 1.000000 10 135.620 1.848 1.734359 28.17 11 -24.210 16.404 1.000000 12 -39.414 10.000 1.615176 58.34 13 -7.702 0.705 1.812529 25.30 14 -13.685 0.969 1.000000 15 -99.112 2.417 1.622857 60.11 16 -14.931 000 1.000000 ______________________________________ Focal-length variation F: 7.5 to 60 Image distance: 22.20 mm Length: 85.20 mm. TABLE VIII __________________________________________________________________________ Dioptric surface 4 7 12 16 __________________________________________________________________________ C 1.63972 10.sup.-2 8.75499 10.sup.-2 -2.53715 10.sup.-2 -6.69741 10.sup.-2 λ 1.68233 10.sup.-1 -7.55918 10.sup.-1 0.00000 00000 ε.sub.2 -5.59326 10.sup.-8 1.61978 10.sup.-5 -2.23860 10.sup.-4 -3.68018 10.sup.-6 ε.sub.3 1.644888 10.sup.-10 -4.29937 10.sup.-7 -1.06579 10.sup.-6 2.28552 10.sup.-8 ε.sub.4 0.00000 0.00000 0.00000 0.00000 ε.sub.5 0.00000 0.00000 0.00000 0.00000 __________________________________________________________________________

Claim 12

A variable focal length objective lens for focusing an image of an object at a stationary image plane, said lens having a free image distance smaller than 22 mm and comprising components, each having at least one lens element, arranged along an optical axis, including: (a) first and second stationary components arranged in order between an object field and the stationary image plane, said components having positive focal lengths; and (b) first and second movable components, each comprising a single element, arranged in order between the first and second stationary components, said first movable component having a negative focal length and said second movable component having a positive focal length, at least one of said single elements having an aspherical surface, said movable components being axially displaceable relative to each other to effect a focal length variation of at least 5 to 1.

Claim 13

A variable focal length objective lens for focusing an image of an object at a stationary image plane, said lens having a free image distance smaller than 22 mm and comprising components, each having at least one lens element, arranged along an optical axis, including: (a) first and second stationary components arranged in order between an object field and the stationary image plane, said components having positive focal lengths; and (b) first and second movable components, each comprising a single element, arranged in order between the first and second stationary components, said first movable component having a negative focal length and said second movable component having a positive focal length, at least one of said single elements having an aspherical surface, said movable components being axially displaceable relative to each other to effect a focal length variation of at least 5 to 1.

Claim 14

A variable focal length objective lens for focusing an image of an object at a stationary image plane, said lens having a free image distance smaller than 22 mm and comprising components, each having at least one lens element, arranged along an optical axis, including: (a) first and second stationary components arranged in order between an object field and the stationary image plane, said first stationary component having a focal length F 1 ; and (b) first, second and third movable components, each comprising a single element, arranged in order between the first and second stationary components and having focal lengths F 2 , F 3 and F 4 , respectively, where F 2 /F.sub. 1 and F 3 /F 1 are negative and F 4 /F 1 is positive, at least one of said single elements having an aspherical surface, said movable components being axially displaceable relative to each other to effect a focal length variation of at least 5 to 1.

Claim 15

A variable focal length objective lens for focusing an image of an object at a stationary image plane, said lens having a free image distance smaller than 22 mm and comprising components, each having at least one lens element, arranged along an optical axis, including: (a) first and second stationary components arranged in order between an object field and the stationary image plane, said first stationary component having a focal length F 1 ; and (b) first, second and third movable components, each comprising a single element, arranged in order between the first and second stationary components and having focal lengths F 2 , F 3 and F 4 , respectively, where F 2 /F.sub. 1 and F 3 /F 1 are negative and F 4 /F 1 is positive, at least one of said single elements having an aspherical surface, said movable components being axially displaceable relative to each other to effect a focal length variation of at least 5 to 1.

Claim 16

A variable focal length objective lens as in claim 8 or 9, characterized in that the aperture is F/1.8, and having the physical characteristics specified in the following Tables III and IV, where the dioptric surfaces of the objective are designated 1 to 20 from the object field to the image field, where E designates the axial distance between designated surfaces for the focal length F=7.90 mm, where n designates the refractive index, where ν designates the Abbe dispersion number, and where the symbols C, λ, ε i represent coefficients in the following equation describing the cross sections of the aspherical dioptric surfaces 7, 8, 10 in a plane which passes through the optical axis ##EQU6## the abscissa x being measured from the apex of the dioptric surface along the optical axis and the ordinate perpendicularly to said axis: TABLE III ______________________________________ Dioptric E R surface (mm) (mm) n ν ______________________________________ 1 115.145 2.935 1.723153 29.26 2 46.191 11.768 1.622857 60.11 3 -248.840 0.050 1.000000 4 63.147 5.243 1.622857 60.11 5 135.414 2.507 1.000000 6 -19.756 0.688 1.591288 60.94 7 11.786 3.279 1.000000 8 237.568 1.680 1.584777 40.53 9 -51.022 59.431 1.000000 10 42.857 2.329 1.584777 40.53 11 -31.066 7.373 1.000000 12 550.809 3.487 1.622857 60.11 13 -16.221 0.040 1.000000 14 -401.781 0.788 1.812529 25.30 15 13.928 1.259 1.000000 16 42.759 2.200 1.622857 60.11 17 -26.586 0.050 1.000000 18 ∞ 26.500 1.518727 64.04 19 ∞ 0.000 1.000000 ______________________________________ Focal-length variation F: 7.90 to 64 mm. Image distance after prism: 4.25 mm Length: 131.66 mm TABLE IV ______________________________________ Dioptric surface 7 8 10 ______________________________________ C 8,48454 10.sup.-2 4,20932 10.sup.-3 2,33336 10.sup.-2 λ -8,64111 10.sup.-1 -6,87745 10.sup.-2 -5,06288 ε.sub.2 -1,01718 10.sup.-4 2,05245 10.sup.-6 -7,45166 10.sup.-5 ε.sub.3 -1,33362 10.sup.-7 -4,29973 10.sup.-8 -2,89507 10.sup.-7 ε.sub.4 -1,23607 10.sup.-8 1,41858 10.sup.-9 1,75248 10.sup.-9 ε.sub.5 1,19575 10.sup.-10 -1,73662 10.sup.-11 -5,15778 10.sup.-11 ______________________________________