In marking execution mode, after initialization, a scanning control signal based on predetermined marking data and condition data is sent to a scanning head so that a beam spot of a YAG laser beam scans spirally on the interior of a predetermined first black cell in a two-dimensional bar code marking...http://www.google.com.tw/patents/US6121574?utm_source=gb-gplus-share專利 US6121574 - Two-dimensional bar code laser marking method
