Compact catadioptric apochromat system

Claim 2

A compact catadioptric system for use as a long focal length photographic objective comprising in axial alignment: a solid refractive support element consisting of a body portion and a portion of smaller diameter projecting forward from the front end of the body portion, a pair of spherical internal reflecting surfaces on opposite ends of the support element consisting of an annular convergent reflecting surface on the rear end of the support element having an opening therethrough and a circular divergent reflecting surface on the forward end of the forwardly projecting portion of the support element to receive light from the convergent reflecting surface and reflect said light through the opening in the annular reflecting surface, and means producing apochromatism of the system comprising a front afocal doublet consisting of a positive lens in front of a negative lens, said positive and negative lenses each having an axial aperture therethrough and being positioned in front of the body portion of the support element with the forwardly projecting portion of the support element extending through the latter apertures, said positive lens and said support element being of the same material whose index of refraction differs by a substantial amount from the index of refraction of the material of the negative lens, and the material of the negative lens having substantially the same dispersive power as the material of the positive lens and support element.

Claim 3

The system of claim 1 in which the index of refraction of the material of the positive lens and support element differs substantially from the index of refraction of the material of the negative lens.

Claim 4

The system of claim 1 in which the index of refraction of the material of the positive lens and support element is on the order of about 17 percent less than the index of refraction of the material of the negative lens, and in which the difference between the dispersion of the material of the positive lens and support elements and the dispersion of the material of the negative lens is less than 1 percent.

Claim 5

The system of claim 3 in which the positIve and negative lenses of said afocal doublet are spaced apart with an air space between.

Claim 6

The system of claim 1 in which the said body portion has a central aperture extending in from the rear and which includes lens means in the latter aperture for increasing the focal length of the system and correcting aberrations.

Claim 7

The system of claim 5 in which said lens means comprise in axial alignment from front to rear, a second negative lens, a cemented doublet and a third negative lens.

Claim 8

The system of claim 6 in which said cemented doublet and said third negative lens are mounted in an axially movable support for changing the focus of the system.

Claim 9

A compact catadioptric system for use as a long focal length photographic objective comprising in axial alignment: a solid refractive support element (CDE) consisting of a body portion (CD) and a portion (E) of smaller diameter projecting forward from the front end of the body portion, said body portion having a central aperture extending in from the rear, a pair of spherical internal reflecting surfaces on opposite ends of the support element consisting of an annular convergent reflecting surface on the rear end of the support element around said aperture and a circular divergent reflecting surface on the forward end of the forwardly projecting portion of the support element to receive light from the convergent reflecting surface and reflect said light into said central aperture, and means producing apochromatism of the system comprising a front afocal doublet consisting of a positive lens in front of a negative lens, said positive and negative lenses each having an axial aperture therethrough and being positioned in front of the body portion of the support element with the forwardly projecting portion of the support element extending through the latter aperture, and said system being characterized by the following constructional data: Focal Length 1400 MM (54.9949 inches) Relative Aperture f/20 Field of View 1.9* Overall Length 3 inches Front Vertex Distance 5.10 inches Image Distance 2.31 inches Axial distance disper-Ele-from Index of re- sionment radius thickness spacing entrance fraction (V no.) A R1 0.5000 0.000 1.541 47.2 14.6874 R2 0.500 -3.40960.050 B R3 0.1000 0.550 1.803 46.8 -3.3873 R4 0.650 -21.97120.000C-D R5 2.3000 0.650 1.541 47.2 433.5875 R6 2.950 -7.3398-1.000E-C R7 1.7000 -0.050 1.541 47.2 -1.6553 R8 Infinity 1.650

Claim 10

A compact catadioptric system for use as a long focal length photographic objective comprising in axial alignment: a solid refractive support element (CDE) consisting of a body portion (CD) and a portion (E) of smaller diameter projecting forward from the front end of the body portion, said body portion having a central aperture extending in from the rear, a pair of spherical internal reflecting surfaces on opposite ends of the support element consisting of an annular convergent reflecting surface on the rear end of the support element around said aperture and a circular divergent reflecting surface on the forward end of the forwardly projecting portion of the support element to receive light from the convergent reflecting surface and reflect said light into said central aperture, and means producing apochromatism of the system comprising a front afocal doublet consisting of a positive lens in front of a negative lens, said positive and negative lenses each having an axial aperture therethrough and being positioned in front of the body portion of the support element with the forwardly projecting portion of the support element extending through the latter aperture, and said system being characterized by the following constructional data: Focal Length 1400 MM (54.9949 inches) Relative Aperture f/20 Field of View 1.9* Overall Length 3 inches Front Vertex Distance 5.10 inches Image Distance 2.31 inches Axial distance disper-Ele-from Index of re- sionment radius thickness spacing entrance fraction (V no.) A R1 0.5000 0.000 1.541 47.2 14.6874 R2 0.500 -3.40960.050 B R3 0.1000 0.550 1.803 46.8 -3.3873 R4 0.650 -21.97120.000C-D R5 2.3000 0.650 1.541 47.2 433.5875 R6 2.950 -7.3398-1.000E-C R7 1.7000 -0.050 1.541 47.2 -1.6553 R8 Infinity 1.650

Claim 11

The system of claim 8 including lens means mounted in the central aperture that extends in from the rear of said support element for increasing the focal length of the system and correcting aberrations.

Claim 12

The system of claim 9 in which said lens means comprise in axial alignment from front to rear, a second negative lens (F), a cemented doublet (GH), and a third negative lens (I) characterized by the following constructional data: axial distance disper-Ele- from index of re- sionment radius thickness spacing entrance fraction (V no.C-F 0.073 F R9 1.1500 1.723 1.621 35.9 6.7448 R10 1.873 3.24510.540 G R11 0.0500 2.413 1.623 56.9 -1.2586 R12 12 2.463 1.20310 H R12 0.1500 2.463 1.621 35.9 1.2031 R13 2.613 -0.97310.0805 I R14 0.1000 2.694 1.623 56.9 -0.7994 R15 15 2.794 1.5730