Eye testing chart

申请公布号：

US4257690(A)

申请号：

US19790030455

申请日期：

1979.04.16

申请公布日期：

1981.03.24

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

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.