公开(公告)号：JPH06187481A

公开(公告)日：1994-07-08

申请号：JP16165393

申请日：1993-06-30

Applicant: SYMBOL TECHNOLOGIES INC

Inventor： ROSA RALPH ,  GREENROSE JAY ,  BEZALEL MENASHE ,  DVORKIS PAUL ,  BARKAN EDWARD ,  BARKAN CHRISTINE

IPC: G06K7/00 ,  G06K5/00 ,  G06K7/10 ,  G06K7/14 ,  G06K19/06

Abstract: PURPOSE: To provide a method for reading a bar code which is encoded by the relative width of one or both of bars and spaces and by the relative height of the bar by scanning with long laser beams across the bar code which is height-modulated or width-modulated. CONSTITUTION: The bar code is scanned by a light source generating almost oval illumination spot 200. The bar code may be a height modulation code (A) or a width modulation code (B). The intensity of light reflected from the bar code changes when the illumination spot crosses the bar code. When the illumination spot 200 crosses the spaces (205'), reflected light intensity reaches a maximum value and it reduces when it crosses a short bar [205" of (A)] or a fine bar [205" of (B)]. Reflected light intensity reaches a minimum value when it crosses the long bar [205"' of (A)] or the thick bar [205"' of (B)]. Consequently, it is clear that the patterns of (A) and (B) become the patterns of reflected light intensity and they can be decoded.