发明名称 Eye testing chart
摘要 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.
申请公布号 US4257690(A) 申请公布日期 1981.03.24
申请号 US19790030455 申请日期 1979.04.16
申请人 MASSACHUSETTS INSTITUTE OF TECHNOLOGY 发明人 HOWLAND, BRADFORD
分类号 A61B3/02;(IPC1-7):A61B3/02;G09F13/16 主分类号 A61B3/02
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