| 摘要 |
<p>PURPOSE:To prevent detection of error by detecting defect of pattern from combination of digitalized signal and appearance frequency thereof. CONSTITUTION:After sampling signal from an optical detector 12 every constant time, digitalization is performed and the title device is given a function to memorize appearance frequency of respective combination as to the every combination of digitalized signals from each optical detector and detects defect of pattern from the combination of digitalized signal and appearance frequency thereof. That is, a storage device 15 is set to readout-mode by lead-light controller 15 and reads out address data DOUT of the storage device 15 corresponding by one-to-one to 4Xn bit information decided by pattern formation of projecting position. Subsequently, after the storage device 15 is set to lettering-mode by the lead-light controller 16, DOUT+1 data is written to DIN (the same address) by an additional circuit 17. Whether which address of the storage device 15 is it addressed at how many times or not is detected by means of repeating such a operation every clock period.</p> |
