Four mirror afocal wide field of view optical system

Claim 2

An afocal optical system comprising: a primary mirror defining an optical axis, said primary mirror having a non-spherical reflective surface; a secondary mirror having a non-spherical reflective surface which is tilted and decentered with respect to said optical axis; a tertiary mirror having a non-spherical reflective surface which is tilted and decentered with respect to said optical axis; a quaternary mirror having a non-spherical reflective surface which is tilted and decentered with respect to said optical axis; said primary, secondary, tertiary, and quaternary mirrors having surfaces shaped to create a focus at infinity and reflect through an exit pupil, said exit pupil providing the system with a field area of view greater than a 5 degree circle; said system being off axis in aperture and field to produce said positions of said reflective surface of said primary mirror and said exit pupil.

Claim 3

The system according to claim 1 wherein at least one of said mirrors is a negative reflective mirror.

Claim 4

The system according to claim 1 wherein a field stop is positioned between said tertiary and quaternary mirrors.

Claim 5

The system according to claim 1 wherein the entrance pupil for said optical system is positioned in front of said primary mirror.

Claim 6

An afocal wide field of view optical system comprising: a primary mirror defining an optical axis, said primary mirror having a conic ellipsoid reflective surface on one side of said optical axis; a secondary mirror having a conic hyperboloid reflective surface which is tilted and decentered with respect to said optical axis; a tertiary mirror having a conic hyperboloid reflective surface which is tilted and decentered with respect to said optical axis; a quaternary mirror having a conic oblate spheroid reflective surface which is tilted and decentered with respect to said optical axis; said primary, secondary, tertiary, and quaternary mirrors having surfaces shaped to create a focus at infinity and reflect through an exit pupil; said optical system being off axis in aperture and field to determine said positions of said primary mirror and said exit pupil.

Claim 7

An afocal wide field of view optical system comprising: a primary mirror defining an optical axis, said primary mirror having a conic ellipsoid reflective surface on one side of said optical axis; a secondary mirror having a conic hyperboloid reflective surface which is tilted and decentered with respect to said optical axis; a tertiary mirror having a conic hyperboloid reflective surface which is tilted and decentered with respect to said optical axis; a quaternary mirror having a conic oblate spheroid reflective surface which is tilted and decentered with respect to said optical axis; said primary, secondary, tertiary, and quaternary mirrors having surfaces shaped to create a focus at infinity and reflect through an exit pupil; said optical system being off axis in aperture and field to determine said positions of said primary mirror and said exit pupil.

Claim 8

The optical system according to claim 5 wherein a field stop is positioned between said tertiary and quaternary mirrors.

Claim 9

The optical system according to claim 5 wherein a collimated beam is projected as said exit pupil.

Claim 10

The optical system according to claim 7 wherein a field stop is positioned between said tertiary and quaternary mirrors.

Claim 11

The optical system according to claim 8 wherein the entrance pupil for said optical system is positioned in front of said primary mirror.

Claim 12

The optical system according to claim 5 wherein said primary, tertiary and quaternary mirrors are positive power mirrors and said secondary mirror is a negative power mirror wherein said secondary mirror power balances said primary, tertiary, and quaternary mirrors power providing the system with a flat field condition at the exit pupil.

Claim 13

The optical system according to claim 5 wherein said primary mirror being at a +5° offset field of view angle.

Claim 14

The optical system according to claim 5 wherein the entrance pupil for said optical system is positioned in front of said primary mirror.

Claim 15

The optical system according to claim 5 wherein said system has a circular field of view over about 10°.

Claim 16

The optical system according to claim 9 wherein said system has a circular field of view over about 10°.

Claim 17

The optical system according to claim 14 wherein the system having a 10° circular field of view has the following parameters: __________________________________________________________________________ Description Radius CC Thickness Tilt Decenter __________________________________________________________________________ (12) Primary Mirror -4.10558 -.91746 -1.34369 0 0 (14) Secondary Mirror -1.56908 -1.0630 3.14859 -1.4963 -.01342 (16) Tertiary Mirror -5.69096 -1.3483 -3.43660 7.9665 .07929 (18) Quaternary Mirror 4.58805 .3252 1.19157 29.7497 -2.16465 (22) Exit Pupil INF 0 0 0 -1.3210 (24) Entrance Pupil INF 0 2.2500 0 2.500 Field of View Offset Angle = +5 Degrees Entrance Pupil Dia = 1.0 Inch, Circular Field of View = 10 Degrees, Circular Magnification Ratio = 4× __________________________________________________________________________ (+) Distance are to the right along primary mirror optical axis (+) Radii have centers to the right (+) Decenters are up (+) Tilts are counterclockwise, degrees CC Conic Constant = -(Eccentricity).sup.2 Decenters are done before tilting Thicknesses are between mirror vertices before decenters and tilts are applied. All dimensions are in inches unless specified otherwise.

Claim 18

The optical system according to claim 5 wherein said system has a rectangular field of view of about 10° by 15°.

Claim 19

The optical system according to claim 9 wherein said system has a rectangular field of view of about 10° to 15°.

Claim 20

The optical system according to claim 17 wherein said system having a 10° by 15° rectangular field of view has the following parameters: __________________________________________________________________________ Description Radius CC Thickness Tilt Decenter __________________________________________________________________________ (12) Primary Mirror -4.10558 -.91746 -1.34369 0 0 (14) Secondary Mirror -1.56908 -1.0630 3.14859 -1.4963 -.01342 (16) Tertiary Mirror -5.69096 -1.3483 -3.43660 7.9665 .07929 (18) Quaternary Mirror 4.58805 .3252 1.19157 29.7497 -2.16465 (22) Exit Pupil INF 0 0 0 -1.3210 (24) Entrance Pupil INF 0 2.2500 0 2.500 Field of View Offset Angle = +5 Degrees Entrance Pupil Dia = 1.0 × .75 Inch, Rectangular Pupil Shape (Elevation of Azimuth) Field of View = 10 × 15 Degrees, Rectangular Magnification Ratio = 4× __________________________________________________________________________ Distance are to the right along primary mirror optical axis (+) Radii have centers to the right (+) Decenters are up (+) Tilts are counterclockwise, degrees CC Conic Constant= -(Eccentricity).sup.2 Decenters are done before tilting Thicknesses are between mirror vertices before decenters and tilts are applied. All dimensions are in inches unless specified otherwise.

Claim 21

A four mirror afocal wide field of view optical system comprising: a primary mirror defining an optical axis, said primary mirror having a conic ellipsoid reflective surface on one side of said optical axis; an entrance pupil for said optical system positioned in front of said primary mirror; a secondary mirror having a conic hyperboloid reflective surface which is tilted and decentered with respect to said optical axis; a tertiary mirror having a conic hyperboloid reflective surface which is tilted and decentered with respect to said optical axis; a quaternary mirror having a conic oblate spheroid reflective surface which is tilted and decentered with respect to said optical axis; said primary, secondary, tertiary, and quaternary mirrors having surfaces shaped to create a focus at infinity and reflect through an exit pupil; said exit pupil being on the other side of said optical axis from said reflective surface of said primary mirror; said system being off axis in aperture and field to produce said positions of said reflective surface of said primary mirror and said exit pupil.

Claim 22

A four mirror afocal wide field of view optical system comprising: a primary mirror defining an optical axis, said primary mirror having a conic ellipsoid reflective surface on one side of said optical axis; an entrance pupil for said optical system positioned in front of said primary mirror; a secondary mirror having a conic hyperboloid reflective surface which is tilted and decentered with respect to said optical axis; a tertiary mirror having a conic hyperboloid reflective surface which is tilted and decentered with respect to said optical axis; a quaternary mirror having a conic oblate spheroid reflective surface which is tilted and decentered with respect to said optical axis; said primary, secondary, tertiary, and quaternary mirrors having surfaces shaped to create a focus at infinity and reflect through an exit pupil; said exit pupil being on the other side of said optical axis from said reflective surface of said primary mirror; said system being off axis in aperture and field to produce said positions of said reflective surface of said primary mirror and said exit pupil.

Claim 23

The optical system according to claim 19 wherein a field stop is positioned between said tertiary and quaternary mirrors.

Claim 24

The optical system according to claim 19 wherein a collimated beam is projected at said exit pupil.

Claim 25

The optical system according to claim 21 wherein a field stop is positioned between said tertiary and quaternary mirrors.

Claim 26

The optical system according to claim 19 wherein said primary, tertiary and quaternary mirrors are positive power mirrors and said secondary mirror is a negative power mirror wherein said secondary mirror power balances said primary, tertiary and quaternary mirrors power providing the system with a flat field condition at the exit pupil.

Claim 27

The optical system according to claim 19 wherein said primary mirror being at a +5° offset field of view angle.

Claim 28

The optical system according to claim 19 wherein said system has a circular field of view over about 10°.

Claim 29

The optical system according to claim 22 wherein said system has a circular field of view over about 10°.

Claim 30

The optical system according to claim 26 wherein the system having a 10° circular field of view has the following parameters: __________________________________________________________________________ Description Radius CC Thickness Tilt Decenter __________________________________________________________________________ (12) Primary Mirror -4.10558 -.91746 -1.34369 0 0 (14) Secondary Mirror -1.56908 -1.0630 3.14859 -1.4963 -.01342 (16) Tertiary Mirror -5.69096 -1.3483 -3.43660 7.9665 .07929 (18) Quaternary Mirror 4.58805 .3252 1.19157 29.7497 -2.16465 (22) Exit Pupil INF 0 0 0 -1.3210 (24) Entrance Pupil INF 0 2.2500 0 2.500 Field of View Offset Angle = +5 Degrees Entrance Pupil Dia = 1.0 Inch, Circular Field of View = 10 Degrees, Circular Magnification Ratio = 4× __________________________________________________________________________ (+) Distance are to the right along primary mirror optical axis (+) Radii have centers to the right (+) Decenters are up (+) Tilts are counterclockwise, degrees CC Conic Constant = -(Eccentricity).sup.2 Decenters are done before tilting Thicknesses are between mirror vertices before decenters and tilts are applied. All dimensions are in inches unless specified otherwise.

Claim 31

The optical system according to claim 19 wherein said system has a rectangular field of view of about 10° by 15°.

Claim 32

The optical system according to claim 22 wherein said system has a rectangular field of view of about 10° by 15°.

Claim 33

The optical system according to claim 29 wherein said system having a 10° by 15° rectangular field of view has the following parameters: __________________________________________________________________________ Description Radius CC Thickness Tilt Decenter __________________________________________________________________________ (12) Primary Mirror -4.10558 -.91746 -1.34369 0 0 (14) Secondary Mirror -1.56908 -1.0630 3.14859 -1.4963 -.01342 (16) Tertiary Mirror -5.69096 -1.3483 -3.43660 7.9665 .07929 (18) Quaternary Mirror 4.58805 .3252 1.19157 29.7497 -2.16465 (22) Exit Pupil INF 0 0 0 -1.3210 (24) Entrance Pupil INF 0 2.2500 0 2.500 Field of View Offset Angle = +5 Degrees Entrance Pupil Dia = 1.0 × .75 Inch, Rectangular Pupil Shape (Elevation of Azimuth) Field of View = 10 × 15 Degrees, Rectangular Magnification Ratio = 4× __________________________________________________________________________ Distance are to the right along primary mirror optical axis (+) Radii have centers to the right (+) Decenters are up (+) Tilts are counterclockwise, degrees CC Conic Constant= -(Eccentricity).sup.2 Decenters are done before tilting Thicknesses are between mirror vertices before decenters and tilts are applied. All dimensions are in inches unless specified otherwise.