Eye refractmeter

Optics: eye examining – vision testing and correcting – Spectacles and eyeglasses – Folding

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Details

351 7, 354 62, G03B 2900, A61B 314, A61B 310

Patent

active

042771501

ABSTRACT:
An eye refractmeter comprising a target projecting optical system for projecting an image of a target means through a pupil of a patient's eye to produce a target image on a retina of the eye, an observing optical system including objective lens means for observing the target image through the pupil, and a sighting optical system for observing light reflected at the cornea of the eye to determine that the objective lens means is appropriately spaced from the patient's eye, means being provided in the projecting optical system so that the image of the target means is projected by an infrared ray, half-transparent optical means for passing therethrough one of the light bundles along the observing and sighting optical systems and reflecting the other of the bundles, means for directing both of the light bundles passing through the observing and sighting optical systems to a single image pick-up tube, the half-transparent optical means having a reflecting rate such that more than 50% of the light along the observing optical system and less than 50% of the light along the sighting optical system are directed to the image pick-up tube.

REFERENCES:
patent: 2586973 (1952-02-01), McMillin
patent: 3572909 (1971-03-01), Van Pattern et al.
patent: 3864030 (1975-02-01), Cornsweet
patent: 3871772 (1975-03-01), Munnerlyn et al.
patent: 3880501 (1975-04-01), Munnerlyn
patent: 3883233 (1975-05-01), Guilino
patent: 4098549 (1978-07-01), Matsumura
patent: 4146310 (1979-03-01), Kohayakawa
Mohrman et al., Putting the Knife Edge to the Eye, Optical Engineering, Jul. 1976.

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