公开(公告)号：US3944369A

公开(公告)日：1976-03-16

申请号：US473233

申请日：1974-05-24

申请人： John David Cuthbert ,  Delmer Lee Fehrs ,  David Farnham Munro

发明人： John David Cuthbert ,  Delmer Lee Fehrs ,  David Farnham Munro

IPC分类号： G01N21/956 ,  G01B11/24

CPC分类号： G01N21/95607

摘要： In an optical comparison inspection system a single beam from a scanning light source is split to produce a pair of synchronously scanning focused light beams. One of the beams is directed onto a reference, light affecting patterned workpiece and the other beam is directed onto a similar patterned workpiece to be inspected. Both workpieces are mounted in optically equivalent positions on a traverse table which has a direction of travel orthogonal to parallel planes containing the scanning light beams. Pattern differences are represented by differences in photodetected representations of the two light beams, which are intensity modulated by the patterned workpieces. By electronically gating preselected combinations of the two modulated signals with circuitry employing multiple threshold detection elements, a resultant signal is produced which enables allowable edge aberrations to be discriminated from unacceptable defects in the patterns. Suitable display of the resultant signal permits an operator to rapidly ascertain both the number and location of only unacceptable defects.

摘要翻译： 在光学比较检查系统中，来自扫描光源的单个光束被分割以产生一对同步扫描的聚焦光束。 一个光束被引导到参考光，影响图案化的工件的光，另一个光束被引导到待检查的类似的图案化工件上。 两个工件安装在横向工作台上的光学等效位置上，该横动台具有与包含扫描光束的平行平面垂直的行进方向。 图案差异由两个光束的光电检测表示的差异表示，两个光束被图案化工件强度调制。 通过使用多个阈值检测元件的电路将两个调制信号的预选组合电门选通，产生得到的信号，其使允许的边缘像差与图案中不可接受的缺陷区分开。 所得信号的适当显示允许操作者快速地确定仅有不可接受的缺陷的数量和位置。