Six element unit magnification lens

Claim 2

A lens comprising six air spaced elements, said elements being, in consecutive order, a first positive biconvex element, a first positive meniscus element concave away from said first biconvex element, a first negative element, a second negative element, a second positive meniscus element concave toward said second negative element and a second positive biconvex element, wherein: the ratio of the thickness of said second negative element to said first negative element has a value between 2.0 and 5.0; the ratio of the air space separating said second negative and said second positive meniscus elements to the air space separating said first negative and said first positive meniscus elements has a value between 1.0 and 9.0; and the ratio of the air space separating said second positive elements to the air space separating said first positive elements has a value between 1.0 and 9.0.

Claim 3

A lens comprising, from front to rear, a positive biconvex element, a positive meniscus element concave to the rear, a negative element, an aperture stop, a negative element, a positive meniscus element concave to the front and a positive biconvex element, said lens having an equivalent focal length of 100 millimeters when constructed according to the parameters in the following table: Radius Thickness or Element N V mm Separation mm R1 51.804 1 1.78831 47.4 T1 5.050 R2 -270.13 S1 6.714 R3 38.733 2 1.73400 51.3 T2 3.158 R4 86.041 S2 1.060 R5 Infinity 3 1.62588 35.7 T3 3.523 R6 28.146 S3 6.643 R7 -39.814 4 1.69895 30.1 T4 14.517 R8 156.48 S4 8.189 R9 -112.62 5 1.73400 51.3 T5 3.065 R10 -53.643 S5 8.474 R11 176.61 6 1.71300 53.9 T6 4.530 R12 -91.830 wherein, from front to rear, the lens elements are numbered from 1-6, the corresponding indices of refraction, N, and Abbe numbers, V, are for the 0.5876 micron Helium line of the spectrum, the radii are numbered from R1 to R12, the thicknesses are numbered from T1 to T6 and the air spaces are numbered from S1 to S5.

Claim 4

A lens comprising, from front to rear, a positive biconvex element, a positive meniscus element concave to the rear, a negative element, an aperture stop, a negative element, a positive meniscus element concave to the front and a positive biconvex element, said lens having an equivalent focal length of 100 millimeters when constructed according to the parameters in the following table: Radius Thickness or Element N V mm Separation mm R1 51.804 1 1.78831 47.4 T1 5.050 R2 -270.13 S1 6.714 R3 38.733 2 1.73400 51.3 T2 3.158 R4 86.041 S2 1.060 R5 Infinity 3 1.62588 35.7 T3 3.523 R6 28.146 S3 6.643 R7 -39.814 4 1.69895 30.1 T4 14.517 R8 156.48 S4 8.189 R9 -112.62 5 1.73400 51.3 T5 3.065 R10 -53.643 S5 8.474 R11 176.61 6 1.71300 53.9 T6 4.530 R12 -91.830 wherein, from front to rear, the lens elements are numbered from 1-6, the corresponding indices of refraction, N, and Abbe numbers, V, are for the 0.5876 micron Helium line of the spectrum, the radii are numbered from R1 to R12, the thicknesses are numbered from T1 to T6 and the air spaces are numbered from S1 to S5.

Claim 5

A lens comprising, from front to rear, a positive biconvex element, a positive meniscus element concave to the rear, a negative element, an aperture stop, a negative element, a positive meniscus element concave to the front and a positive biconvex element, said lens having an equivalent focal length of 100 millimeters when constructed according to the parameters in the following table: Radius Thickness or Element N V mm Separation mm R1 52.093 1 1.78821 47.5 T1 5.080 R2 -266.30 S1 6.862 R3 38.752 2 1.73252 51.7 T2 3.135 R4 85.900 S2 0.983 R5 Infinity 3 1.62552 35.8 T3 3.619 R6 28.267 S3 6.483 R7 -39.834 4 1.69864 30.1 T4 14.332 R8 158.81 S4 8.495 R9 -113.08 5 1.73252 51.7 T5 3.053 R10 -53.670 S5 8.202 R11 177.80 6 1.71324 54.0 T6 4.515 R12 -92.566 wherein, from front to rear, the lens elements are numbered from 1-6, the corresponding indices of refraction, N, and Abbe numbers, V, are for the 0.5876 micron Helium line of the spectrum, the radii are numbered from R1 to R12, the thicknesses are numbered from T1 to T6 and the air spaces are numbered from S1 to S5.

Claim 6

A lens comprising, from front to rear, a positive biconvex element, a positive meniscus element concave to the rear, a negative element, an aperture stop, a negative element, a positive meniscus element concave to the front and a positive biconvex element, said lens having an equivalent focal length of 100 millimeters when constructed according to the parameters in the following table: Radius Thickness or Element N V mm Separation mm R1 52.093 1 1.78821 47.5 T1 5.080 R2 -266.30 S1 6.862 R3 38.752 2 1.73252 51.7 T2 3.135 R4 85.900 S2 0.983 R5 Infinity 3 1.62552 35.8 T3 3.619 R6 28.267 S3 6.483 R7 -39.834 4 1.69864 30.1 T4 14.332 R8 158.81 S4 8.495 R9 -113.08 5 1.73252 51.7 T5 3.053 R10 -53.670 S5 8.202 R11 177.80 6 1.71324 54.0 T6 4.515 R12 -92.566 wherein, from front to rear, the lens elements are numbered from 1-6, the corresponding indices of refraction, N, and Abbe numbers, V, are for the 0.5876 micron Helium line of the spectrum, the radii are numbered from R1 to R12, the thicknesses are numbered from T1 to T6 and the air spaces are numbered from S1 to S5.

Claim 7

A lens comprising from front to rear, a positive biconvex element, a positive meniscus element concave to the rear, a negative element, an aperture stop, a negative element, a positive meniscus element concave to the front and a positive biconvex element, said lens having an equivalent focal length of 100 millimeters when constructed according to the parameters in the following table: Radius Thickness or Element N V mm Separation mm R1 53.240 1 1.78831 47.4 T1 5.130 R2 -248.90 S1 1.975 R3 41.102 2 1.73400 51.3 T2 3.080 R4 84.269 S2 2.740 R5 1505.0 3 1.62588 35.7 T3 6.003 R6 27.657 S3 7.411 R7 -38.719 4 1.69895 30.1 T4 12.888 R8 202.20 S4 3.677 R9 -113.075 1.73400 51.3 T5 2.823 R10 -48.741 S5 16.881 R11 196.55 6 1.71300 53.8 T6 4.394 R12 -92.355 wherein, from front to rear, the lens elements are numbered from 1-6, the corresponding indices of refraction, N, and Abbe numbers, V, are for the 0.5876 micron Helium line of the spectrum, the radii are numbered from R1 to R12, the thicknesses are numbered from T1 to T6 and the air spaces are numbered from S1 to S5.

Claim 8

A lens comprising from front to rear, a positive biconvex element, a positive meniscus element concave to the rear, a negative element, an aperture stop, a negative element, a positive meniscus element concave to the front and a positive biconvex element, said lens having an equivalent focal length of 100 millimeters when constructed according to the parameters in the following table: Radius Thickness or Element N V mm Separation mm R1 53.240 1 1.78831 47.4 T1 5.130 R2 -248.90 S1 1.975 R3 41.102 2 1.73400 51.3 T2 3.080 R4 84.269 S2 2.740 R5 1505.0 3 1.62588 35.7 T3 6.003 R6 27.657 S3 7.411 R7 -38.719 4 1.69895 30.1 T4 12.888 R8 202.20 S4 3.677 R9 -113.075 1.73400 51.3 T5 2.823 R10 -48.741 S5 16.881 R11 196.55 6 1.71300 53.8 T6 4.394 R12 -92.355 wherein, from front to rear, the lens elements are numbered from 1-6, the corresponding indices of refraction, N, and Abbe numbers, V, are for the 0.5876 micron Helium line of the spectrum, the radii are numbered from R1 to R12, the thicknesses are numbered from T1 to T6 and the air spaces are numbered from S1 to S5.