Optics: eye examining – vision testing and correcting – Spectacles and eyeglasses – Folding
Patent
1979-04-16
1981-03-24
Corbin, John K.
Optics: eye examining, vision testing and correcting
Spectacles and eyeglasses
Folding
40582, A61B 302, G09F 1316
Patent
active
042576903
ABSTRACT:
An eye chart having a plurality of rows of letters where each letter is composed of a line-stroke having a plurality of adjoining black and white segments to provide an average reflectance which is the same as the reflectance of the gray background of the chart. Each row of the letters utilizes a different width line stroke (the line segments thereof are proportioned correspondingly). The sizes of the letters of each row are geometrically decreasing and are preferably in proportion to the width of the line stroke.
REFERENCES:
patent: 2385992 (1945-10-01), Jobe
patent: 2463813 (1949-03-01), Shepard
Americant Optical Vision, "AO Project-O-Chart Projects a Variety of Subjective Eye Tests".
"Clinical Refraction", 3rd Edition, by I. M. Borish, pp. 380, 382-386.
Bovernick Rodney B.
Corbin John K.
Massachusetts Institute of Technology
Santa Martin M.
Smith, Jr. Arthur A.
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