公开(公告)号：US5552591B1

公开(公告)日：2000-05-02

申请号：US2129893

申请日：1993-02-22

Applicant: IBM

Inventor： BOSSEN DOUGLAS C ,  CHEN CHIN-LONG ,  DILL FREDERICK H ,  GOODMAN DOUGLAS S ,  HSIAO MU-YUE ,  MCCANN PAUL V ,  MULLIGAN JAMES M ,  RAND RICKY A

IPC: G06K1/12 ,  G06K7/016 ,  G06K7/10 ,  G06K19/06

CPC classification number: G06K7/10861 ,  G06K1/126 ,  G06K7/0166 ,  G06K19/06028 ,  G06K2019/06253

公开(公告)号：CA2011296A1

公开(公告)日：1990-11-15

申请号：CA2011296

申请日：1990-03-01

Applicant: IBM

Inventor： BOSSEN DOUGLAS C ,  CHEN CHIN L ,  DILL FREDERICK H ,  GOODMAN DOUGLAS S ,  HSIAO MU Y ,  MCCANN PAUL V ,  MULLIGAN JAMES M ,  RAND RICKY A

IPC: G06K1/12 ,  G06K7/016 ,  G06K7/10 ,  G06K19/06 ,  G06K1/00

Abstract: PRESENCE/ABSENCE BAR CODE A single width bar code exhibiting inherent self clocking characteristics is provided so as to be particularly useful in the identification of semiconductor wafers in very large scale integrated circuit manufacturing processes. The codes described herein are robust, reliable and highly readable even in the face of relatively high variations in scanning speed The codes are also desirably dense in terms of character representations per linear centimeter, an important consideration in semiconductor manufacturing wherein space on the chips and the wafer is at a premium. Additionally, a preferred embodiment of the present invention exhibits a minimum number for the maximum number of spaces between adjacent bars in code symbol sequences. P09-89-002