Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Patent
1997-01-31
1998-04-21
Dang, Hung X.
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
351221, 354 62, A61B 314, A61B 310
Patent
active
057423741
ABSTRACT:
A fundus camera for photographing fundus of an eye to be examined, comprises observing illumination/target projection optical system provided with a slit-plate having a pin-hole aperture and a ring-slit, for illuminating the eye to be examined with an illumination light bundle for use in observation that is formed by the ring-slit to be ring-shaped by illuminating the slit-plate uniformly, and for projecting an alignment index onto a cornea of the eye to be examined by using a light bundle that has passed through the pin-hole aperture, photographing illumination optical system for illuminating the eye to be examined with a ring-shaped illumination light bundle for use in photography by using a part of optical path of the observing illumination/target projection optical system, observation optical system for observing the focused condition of an image of the alignment index projected onto the cornea of the eye to be examined and the fundus of the eye to be examined by using the observing illumination/target projection optical system, and photographing optical system using a part of optical path of the observation optical system and for photographing the fundus of the eye to be examined that is illuminated with the photographing illumination optical system, whereby the suitability of the alignment is determined by observing the focused condition of the image of the alignment index by using the observation optical system.
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Kawamura Masunori
Nanjo Tsuguo
Dang Hung X.
Nidek Company, Ltd.
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