Infra-red optical systems

Claim 2

An "eye-piece" system for use in a non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope in which an intermediate image is formed, the "eye-piece" system comprising at least three lens elements of infra-red transmitting material operative with radiation in at least one of the 3 to 5.5 and 8 to 13 micron wavebands, the three lens elements including a back element of positive power having a back surface which is either convex or concave, a front surface which is convex, and a pair of elements which are closely spaced to define a gas lens therebetween, the back element of the pair having a convex back surface and the front element of the pair having a concave front surface, the pair of elements in combination with the gas lens therebetween being of positive power.

Claim 3

An "eye-piece" system for use in a non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising at least three lens elements of infra-red transmitting material operative with radiation in at least one of the 3 to 5.5 and 8 to 13 micron wavebands, the three lens elements including a back element of positive power having a back surface which is either convex or concave, a front surface which is convex, and a pair of elements which are closely spaced to define a gas lens therebetween, the back element of the pair having a convex back surface and the front element of the pair having a concave front surface with an absolute value of radius of curvature less than that of the convex back surface of the back element of the pair, the pair of elements in combination with the gas lens therebetween being of positive power.

Claim 4

An "eye-piece" system for use in a non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising at least three lens elements of infra-red transmitting material operative with radiation in at least one of the 3 to 5.5 and 8 to 13 micron wavebands, the three lens elements including a back element of positive power having a back surface which is either convex or concave, a front surface which is convex, and a pair of elements which are closely spaced to define a gas lens therebetween, the back element of the pair having a convex back surface and the front element of the pair having a concave front surface with an absolute value of radius of curvature less than that of the convex back surface of the back element of the pair, the pair of elements in combination with the gas lens therebetween being of positive power.

Claim 5

An "eye-piece" system according to claim 1 or claim 2 in which the back element of the pair is of positive power while the front element of the pair is of negative power.

Claim 6

An "eye-piece" system according to claim 1 or claim 2 in which the gas lens between the elements of the pair is of negative power.

Claim 7

An "eye-piece" system according to claim 1 or claim 2 in which the back element of the pair is meniscus in form having a concave front surface.

Claim 8

An "eye-piece" system according to claim 5 in which the back element of the pair has a concave front surface whose radius of curvature has an absolute value greater than that of its convex back surface.

Claim 9

An "eye-piece" system according to claim 1 or claim 2 in which the front element of the pair is meniscus in form and has a convex back surface.

Claim 10

An "eye-piece" system according to claim 7 in which the front element of the pair has a convex back surface whose radius of curvature has an absolute value greater than that of its concave front surface.

Claim 11

An "eye-piece" system according to claim 1 or claim 2 in which the gas lens between the elements of the pair is bounded at the back by a front concave surface of the back element of the pair and at the front by a back convex surface of the front element of the pair, the back convex surface of the front element of the pair having a radius of curvature with an absolute value greater than that of the front concave surface of the back element of the pair.

Claim 12

An "eye-piece" system according to claim 1 or claim 2 having an associated, positively powered, field lens located near the position of the intermediate image formed in the optical system or telescope.

Claim 13

An "eye-piece" system according to claim 10 in which there is a gas space between the field lens and the front element of said pair of elements, and the intermediate image position is in that gas space.

Claim 14

An "eye-piece" system according to claim 10 in which the field lens is located close to the front element of said pair of elements to define a gas lens bounded by the front surface of that front element and the back surface of the field lens.

Claim 15

An "eye-piece" system according to claim 12 in which the gas lens between the field lens and said front element is of negative power.

Claim 16

An "eye-piece" system according to claim 12 in which the gas lens between the field lens and said front element is of similar shape to the gas lens between the elements of said pair of elements.

Claim 17

An "eye-piece" system according to claims 1 or 2 and an objective lens system for collecting and transmitting infra-red radiation thereto.

Claim 18

An "eye-piece" system according to claim 15 wherein the "eye-piece" system is designed to compensate for residual aberrations from said objective lens system.

Claim 19

An "eye-piece" system according to claim 1 or claim 2 and an objective lens system for producing a real image from infra-red radiation from a distant scene or object, said "eye-piece" system positioned to receive infra-red radiation from said real image and to provide a collimated, magnified view of the scene or object at a real exit pupil, and scanning and detector means operative at said exit pupil to scan the collimated, magnified view via imaging means across infra-red detector means.

Claim 20

An "eye-piece" system according to claim 1 or claim 2 in which the infra-red transmitting material is selected from germanium and silicon.

Claim 21

An "eye-piece" system for use in a non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising three lens elements 5, 6 and 7 whose surfaces R9 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R9 -61.079 5 5.080 R10 -180.950 4.894 R11 -133.405 6 29.325 R12 -86.059 40.994 R13 +167.247 7 10.302 R14 +411.769 ______________________________________

Claim 22

An "eye-piece" system for use in a non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising three lens elements 5, 6 and 7 whose surfaces R9 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R9 -61.079 5 5.080 R10 -180.950 4.894 R11 -133.405 6 29.325 R12 -86.059 40.994 R13 +167.247 7 10.302 R14 +411.769 ______________________________________

Claim 23

An "eye-piece" system for use in a non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising three lens elements 5, 6 and 7 whose surfaces R9 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R9 -82.657 5 5.460 R10 -252.638 5.460 R11 -127.622 6 41.830 R12 -103.520 32.850 R13 +172.984 7 11.500 R14 -429.083 ______________________________________

Claim 24

An "eye-piece" system for use in a non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising three lens elements 5, 6 and 7 whose surfaces R9 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R9 -82.657 5 5.460 R10 -252.638 5.460 R11 -127.622 6 41.830 R12 -103.520 32.850 R13 +172.984 7 11.500 R14 -429.083 ______________________________________

Claim 25

An "eye-piece" system for use in a non-Gallilean afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising three lens elements 5, 6 and 7 whose surfaces R9 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R9 -43.336 5 8.001 R10 -146.465 11.430 R11 -63.154 6 12.276 R12 -46.862 0.640 R13 +44.034 7 7.620 R14 +56.889 ______________________________________

Claim 26

An "eye-piece" system for use in a non-Gallilean afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising three lens elements 5, 6 and 7 whose surfaces R9 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R9 -43.336 5 8.001 R10 -146.465 11.430 R11 -63.154 6 12.276 R12 -46.862 0.640 R13 +44.034 7 7.620 R14 +56.889 ______________________________________

Claim 27

A non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope comprising lens elements 1 to 7 whose surfaces R1 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R1 +559.792 1 8.717 R2 -2171.13 6.789 R3 -304.239 2 7.132 R4 -491.582 137.160 R5 +188.496 3 9.880 R6 +335.513 63.315 R7 -5331.65 4 7.925 R8 -315.991 14.094 R9 -61.079 5 5.080 R10 -180.950 4.894 R11 -133.405 6 29.325 R12 -86.059 40.994 R13 +167.247 7 10.302 R14 +411.769 ______________________________________

Claim 28

A non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope comprising lens elements 1 to 7 whose surfaces R1 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R1 +559.792 1 8.717 R2 -2171.13 6.789 R3 -304.239 2 7.132 R4 -491.582 137.160 R5 +188.496 3 9.880 R6 +335.513 63.315 R7 -5331.65 4 7.925 R8 -315.991 14.094 R9 -61.079 5 5.080 R10 -180.950 4.894 R11 -133.405 6 29.325 R12 -86.059 40.994 R13 +167.247 7 10.302 R14 +411.769 ______________________________________

Claim 29

A non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope comprising lens elements 1 to 7 whose surfaces R1 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R1 +569.852 1 8.030 R2 -2980.39 5.660 R3 -308.818 2 7.030 R4 -429.083 129.410 R5 +192.863 3 8.780 R6 +248.110 56.250 R7 +185.853 4 8.020 R8 +500.384 28.130 R9 -82.657 5 5.460 R10 -252.638 5.460 R11 -127.622 6 41.830 R12 -103.520 32.850 R13 +172.984 7 11.500 R14 -429.083 ______________________________________

Claim 30

A non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope comprising lens elements 1 to 7 whose surfaces R1 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R1 +569.852 1 8.030 R2 -2980.39 5.660 R3 -308.818 2 7.030 R4 -429.083 129.410 R5 +192.863 3 8.780 R6 +248.110 56.250 R7 +185.853 4 8.020 R8 +500.384 28.130 R9 -82.657 5 5.460 R10 -252.638 5.460 R11 -127.622 6 41.830 R12 -103.520 32.850 R13 +172.984 7 11.500 R14 -429.083 ______________________________________

Claim 31

A non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope comprising lens elements 1 to 3 and 5 to 7 whose surfaces R1 to R6 and R9 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R1 +269.357 1 6.858 R2 +113.406 - 45.720 R3 +2202.662 2 9.144 R4 -263.157 186.436 R5 +699.526 3 8.001 R6 -678.667 41.910 R9 -43.336 5 8.001 R10 -146.465 11.430 R11 -63.154 6 12.276 R12 -46.862 0.640 R13 +44.034 7 7.620 R14 +56.889 ______________________________________

Claim 32

A non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope comprising lens elements 1 to 3 and 5 to 7 whose surfaces R1 to R6 and R9 to R14 have radii of curvature, and whose elements have axial thicknesses and separations substantially as follows: ______________________________________ Radius of Axial Thickness/ Element Surface Curvature Separation ______________________________________ R1 +269.357 1 6.858 R2 +113.406 - 45.720 R3 +2202.662 2 9.144 R4 -263.157 186.436 R5 +699.526 3 8.001 R6 -678.667 41.910 R9 -43.336 5 8.001 R10 -146.465 11.430 R11 -63.154 6 12.276 R12 -46.862 0.640 R13 +44.034 7 7.620 R14 +56.889 ______________________________________

Claim 33

An "eye-piece" system for use in a non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising at least three lens elements including a back element of positive power having a back surface which is either convex or concave, a front surface which is convex, and a pair of singlet elements which are closely spaced to define a gas lens therebetween, the back singlet element of the pair having a convex back surface and the front singlet element of the pair having a concave front surface, the pair of singlet elements in combination with the gas lens therebetween being of positive power.

Claim 34

An "eye-piece" system for use in a non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising at least three lens elements including a back element of positive power having a back surface which is either convex or concave, a front surface which is convex, and a pair of singlet elements which are closely spaced to define a gas lens therebetween, the back singlet element of the pair having a convex back surface and the front singlet element of the pair having a concave front surface, the pair of singlet elements in combination with the gas lens therebetween being of positive power.

Claim 35

An "eye-piece" system for use in a non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising at least three lens elements including a back element of positive power having a back surface which is either convex or concave, a front surface which is convex, and a pair of singlet elements which are closely spaced to define a gas lens therebetween, the back singlet element of the pair having a convex back surface and the front singlet element of the pair having a concave front surface with an absolute value of radius of curvature less than that of the convex back surface of the back singlet element of the pair, the pair of singlet elements in combination with the gas lens therebetween being of positive power.

Claim 36

An "eye-piece" system for use in a non-Gallilean, afocal, infra-red optical system or afocal, infra-red telescope, the "eye-piece" system comprising at least three lens elements including a back element of positive power having a back surface which is either convex or concave, a front surface which is convex, and a pair of singlet elements which are closely spaced to define a gas lens therebetween, the back singlet element of the pair having a convex back surface and the front singlet element of the pair having a concave front surface with an absolute value of radius of curvature less than that of the convex back surface of the back singlet element of the pair, the pair of singlet elements in combination with the gas lens therebetween being of positive power.