Catadioptric lens system

Claim 2

A Catadioptric lens system comprising in the order of the transmission of a light ray in the system: a positive single lens (L 1 ) having an object side surface convex to the object side; a main-mirror element (M 1 ) concave to the object side; a sub-mirror element (M 2 ) convex to the image side; and a lens component (L R ) of a negative refractive power including the last refracting surface of the system, wherein the axial distance L between the main-mirror element (M 1 ) and the sub-mirror element (M 2 ) fulfills the following condition in relation to the diagonal length D of the rectangular focal plane on which the image is projected: 1.5 D>L>0.5D.

Claim 3

The invention of claim 1, wherein the main-mirror element (M 1 ) is composed of a negative meniscus single lens element concave to the object side, the image side surface of which serves as a reflecting surface faced to the object side, and the central part of the negative meniscus single lens element of the main-mirror with at least one additional lens element serves as the lens component (L R ).

Claim 4

The invention of claim 2, wherein the lens component (L R ) comprises additional lens elements located at both sides of the central part of the negative meniscus single lens element of the main-mirror.

Claim 5

The invention of claim 1, wherein the main-mirror element (M 1 ) is composed of a center-hollowed negative meniscus single lens element concave to the object side, the image side surface of which serves as a reflecting surface faced to the object side, and the lens component (L R ) is located in the hollow of the negative meniscus single lens element.

Claim 6

The invention of claim 1, wherein the sub-mirror element (M 2 ) is composed of a positive meniscus single lens element convex to the image side, the object side surface of which serves as a reflecting surface faced to the image side, and the radii of curvature R 5 and R 6 of the respective image side and object side surfaces of the positive meniscus single lens element fulfill the following condition in relation to the focal length f of the system: ##EQU4##

Claim 7

A Catadioptric lens system comprising in the order of the transmission of a light ray in the system: a positive single lens (L 1 ) having an object side surface convex to the object side; a main-mirror element (M 1 ) composed of a negative meniscus single lens element concave to the object side, the image side surface of which serves as a reflecting surface faced to the object side; a sub-mirror element (M 2 ) composed of a positive meniscus single lens element convex to the image side, the object side surface of which serves as a reflecting surface faced to the image side; and a lens component (L R ) of a negative refractive power including the last refracting surface of the system, wherein the radius of curvature R 5 of the image side surface of the positive meniscus single lens element and the radius of curvature R 6 of the object side surface of the same fulfill the following condition in relation to the focal length f of the system; ##EQU5##

Claim 8

A Catadioptric lens system comprising in the order of the transmission of a light ray in the system: a positive single lens (L 1 ) having an object side surface convex to the object side; a main-mirror element (M 1 ) composed of a negative meniscus single lens element concave to the object side, the image side surface of which serves as a reflecting surface faced to the object side; a sub-mirror element (M 2 ) composed of a positive meniscus single lens element convex to the image side, the object side surface of which serves as a reflecting surface faced to the image side; and a lens component (L R ) of a negative refractive power including the last refracting surface of the system, wherein the radius of curvature R 5 of the image side surface of the positive meniscus single lens element and the radius of curvature R 6 of the object side surface of the same fulfill the following condition in relation to the focal length f of the system; ##EQU5##

Claim 9

The invention of claim 6, wherein the axial distance L between the main-mirror element (M 1 ) and the sub-mirror element (M 2 ) fulfills the following condition in relation to the diagonal length D of the rectangular focal plane on which the image is projected: 1.5D>L>00.5D.

Claim 10

The invention of claim 7, wherein the lens component (L R ) is formed by the central part of the negative meniscus single lens element of the main-mirror and an additional negative meniscus lens element cemented thereto at the object side thereof.

Claim 11

The invention of claim 8, wherein the lens component (L R ) further comprises a further additional negative meniscus lens element concave to the object side located at the image side of negative meniscus single lens element of the main-mirror.

Claim 12

The invention of claim 7, wherein the lens component (L R ) is formed by the central part of the negative meniscus single lens element of the main mirror and an additional lens having an object side surface concave to the object side located at the image side of the negative meniscus single lens element of the main-mirror.

Claim 13

The invention of claim 7, wherein the negative meniscus single lens element has a hollow in the center thereof, and the lens component (L R ) comprises at least a negative meniscus lens concave to the object side located in the hollow of the negative meniscus single lens element of the main-mirror.

Claim 14

Catadioptric lens system comprising the following design parameters: __________________________________________________________________________ f = 100.0 2ω = 9°40' Radius of Axial Refractive Abbe Curvature Distance Index Number __________________________________________________________________________ r.sub.1 60.572 L.sub.1 d.sub.1 2.000 N.sub.1 1.5176 ν.sub.1 53.5 r.sub.2 173.817 d.sub.2 15.600 r.sub.3 -29.825 d.sub.3 1.600 N.sub.2 1.5168 ν.sub.2 64.1 M.sub.1 r.sub.4 -51.174 d.sub.3' -1.600 N.sub.2' -1.5168 ν.sub.2' 64.1 r.sub.3' -29.825 d.sub.4 -13.600 r.sub.5 -19.373 d.sub.5 -1.000 N.sub.3 -1.5168 ν.sub.3 64.1 M.sub.2 r.sub.6 -36.927 d.sub.5' 1.000 N.sub.3' 1.5168 ν.sub.3' 64.1 r.sub.5' -19.373 d.sub.4' 13.600 r.sub.3" -29.825 M.sub.1 d.sub.3" 1.600 N.sub.2" 1.5168 ν.sub.2" 64.1 r.sub.4' -51.174 d.sub.6 1.200 L.sub.R r.sub.7 -13.015 d.sub.7 0.560 N.sub.4 1.5168 ν.sub.4 64.1 r.sub.8 266.647 d.sub.8 0.760 N.sub.5 11.7400 ν.sub.5 28.3 r.sub.9 -77.979 D = 17.3 L = 13.6 f.sub.R = -27.15 __________________________________________________________________________

Claim 15

Catadioptric lens system comprising the following design parameters: __________________________________________________________________________ f = 100.0 2ω = 9°40' Radius of Axial Refractive Abbe Curvature Distance Index Number __________________________________________________________________________ r.sub.1 60.572 L.sub.1 d.sub.1 2.000 N.sub.1 1.5176 ν.sub.1 53.5 r.sub.2 173.817 d.sub.2 15.600 r.sub.3 -29.825 d.sub.3 1.600 N.sub.2 1.5168 ν.sub.2 64.1 M.sub.1 r.sub.4 -51.174 d.sub.3' -1.600 N.sub.2' -1.5168 ν.sub.2' 64.1 r.sub.3' -29.825 d.sub.4 -13.600 r.sub.5 -19.373 d.sub.5 -1.000 N.sub.3 -1.5168 ν.sub.3 64.1 M.sub.2 r.sub.6 -36.927 d.sub.5' 1.000 N.sub.3' 1.5168 ν.sub.3' 64.1 r.sub.5' -19.373 d.sub.4' 13.600 r.sub.3" -29.825 M.sub.1 d.sub.3" 1.600 N.sub.2" 1.5168 ν.sub.2" 64.1 r.sub.4' -51.174 d.sub.6 1.200 L.sub.R r.sub.7 -13.015 d.sub.7 0.560 N.sub.4 1.5168 ν.sub.4 64.1 r.sub.8 266.647 d.sub.8 0.760 N.sub.5 11.7400 ν.sub.5 28.3 r.sub.9 -77.979 D = 17.3 L = 13.6 f.sub.R = -27.15 __________________________________________________________________________