| 摘要 |
799,812. Ophthalmic photography. ZEISSSTIFTUNG, C., [trading as ZEISS. C.], [Firm of]. Sept. 1, 1955 [Sept. 2, 1954], No. 25090/55. Class 97(1) In an illuminating arrangement for photographing the fundus of the eye in which intermediate images of source 1 are formed adjacent an inclined mirror 5 and at 3, in the plane of co-axial diaphragms 9 and 10, the sizes of apertured diaphragm 9 and central obscuring diaphragm 10 are adjustable, the adjustment of the latter being such that the image conjugate with its corneal image and formed adjacent an aperture 6, preferably provided in mirror 5, can be made larger than the aperture 6. The annular illuminated area 1<SP>1</SP> projected on the cornea 8 is internally bounded by a sharply demarcated image of the periphery of diaphragm 10 and the size of diaphragm 10 is preferably adjusted so that area 1<SP>1</SP> is separated from a central area of the cornea 8, the emergent rays from which all pass through aperture 6, by an annular zone free from incident light. Colour fringes at the inner periphery of the ring- shaped image 3 of a ring-shaped source 1 are obscured by diaphragm 10. The colour fringes at the outer periphery are obscured by diaphragm 9 and the maximum illumination of the eye, especially for colour photography is obtained by arranging that the image of the source 1 on the cornea 8, when the diaphragm 9 is removed, is larger than the pupil of the eye and, when the diaphragm is replaced, is slightly smaller than the pupil. Lenses 4 and 7 are chromatically corrected and photographic light sensitive material is placed at 12. Specification 782,546 is referred to.
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