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US 5,327,289 AGranted
Luminous flux separating optical system
AssigneeFuji Photo Optical Co., Ltd.
InventorsFumio Watanabe, Satoshi Yahagi
Life of this patent
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Abstract
A color separation prism system for use in a TV camera which can separate R, G and B colors. The color separation prism system of the invention includes one or more air gaps each of which is formed between the prisms in a wedge shape that is open on the converging side of a luminous flux passing through the air gap. The use of the wedge-shaped air gap can reduce the possibility of generation of an astigmatism to thereby prevent deterioration of the performance of an optical system formed of the above-mentioned color separation prisms.
Claims26
A luminous flux separating optical system comprising:
- a plurality of prisms;
- and
- an air gap between the plurality of prisms which is not perpendicular to an optical axis of said optical system;
- wherein said air gap is a wedge shape, open on a converging side of a luminous flux passing through said air gap;
- wherein a wedge angle, .delta., of said air gap equals:
- ##EQU6## where d=thickness of a center of said air gap,
- n=refractive index of said plurality of prisms,
- .theta.=angle formed between said air gap and a surface perpendicular to the optical axis, and
- L=equivalent air thickness from said air gap to an image-forming position.
6 more elements
An optical system comprising:
- a first prism;
- a second prism;
- a third prism;
- an air gap formed between said first and second prisms, wherein said air gap is not perpendicular to an optical axis of said optical system;
- and
- a dichroic coating on adjacent surfaces of said second and third prisms;
- wherein said air gap is a wedge shape, open on a converging side of a luminous flux passing through said air gap wherein a wedge angle, .delta., of said air gap equals:
- ##EQU7## where d=thickness of a center of said air gap,
- n=refractive index of said plurality of prisms,
- .theta.=angle formed between said air gap and a surface perpendicular to the optical axis, and
- L=equivalent air thickness from said air gap to an image-forming position.
8 more elements
An optical system comprising:
- a first prism;
- a second prism;
- a third prism;
- a first dichroic coating on said first prism;
- an air gap not perpendicular to the optical axis of the optical system between the first and second prisms;
- and
- a second dichroic coating on adjacent surfaces of said second and third prisms;
- wherein said air gap is a wedge shape, open on a converging side of a luminous flux passing through said air gap wherein a wedge angle, .delta., of said air gap equals:
- ##EQU8## where d=thickness of a center of said air gap,
- n=refractive index of said plurality of prisms,
- .theta.=angle formed between said air gap and a surface perpendicular to the optical axis, and
- L=equivalent air thickness from said air gap to an image-forming position.
9 more elements
An optical system comprising:
- a first prism;
- a second prism;
- a third prism;
- an air gap formed between said first and second prisms, wherein said air gap is not perpendicular to an optical axis of said optical system;
- and
- a dichroic coating on adjacent surfaces of said second and third prisms;
- wherein said air gap is a wedge shape, open on a converging side of a luminous flux passing through said air gap wherein a wedge angle, .delta., of said air gap is between:
- ##EQU9## where d=thickness of a center of said air gap,
- n=refractive index of said plurality of prisms,
- .theta.=angle formed between said air gap and a surface perpendicular to the optical axis, and
- L=equivalent air thickness from said air gap to an image-forming position.
8 more elements
An optical system comprising:
- a first prism;
- a second prism;
- a third prism;
- a first dichroic coating on said first prism;
- an air gap not perpendicular to the optical axis of the optical system between the first and second prisms;
- and
- a second dichroic coating on adjacent surfaces of said second and third prisms;
- wherein said air gap is a wedge shape, open on a converging side of a luminous flux passing through said air gap wherein a wedge angle, .delta., of said air gap is between:
- ##EQU10## where d=thickness of a center of said air gap,
- n=refractive index of said plurality of prisms,
- .theta.=angle formed between said air gap and a surface perpendicular to the optical axis, and
- L=equivalent air thickness from said air gap to an image-forming position.
9 more elements
A luminous flux separating optical system comprising:
- a plurality of prisms;
- and
- an air gap between the plurality of prisms which is not perpendicular to an optical axis of said optical system;
- wherein said air gap is a wedge shape, open on a converging side of a luminous flux passing through said air gap;
- wherein a wedge angle, .delta., of said air gap equals:
- ##EQU11## where d=thickness of a center of said air gap,
- n=refractive index of said plurality of prisms,
- .theta.=angle formed between said air gap and a surface perpendicular to the optical axis, and
- L=equivalent air thickness from said air gap to an image-forming position.
6 more elements
Dependencies are inferred from the claim text.