Bar Code System for Printed Circuit Boards
Original Publication Date: 1985-Aug-01
Included in the Prior Art Database: 2005-Feb-19
There is increasing interest in using bar codes for the control of manufacturing processes to increase quality through component tracking, queuing, etc. Current bar code systems use either a printed pattern of ink giving alternating regions of different absorptivity, or laser scribing or embossing to give alternating regions of specular and diffuse reflectivity. While these patterns can be used to mark components that are subsequently assembled without additional processing (of the components), they present a problem for components, such as printed circuit boards, etc., that may undergo many additional processing steps. These steps may include cleaning (chemical and abrasive), photoresist application and exposure, development, etching, metallization, drilling, etc.