Printed Circuit Laser Cut Fusible Link
Original Publication Date: 1988-Mar-01
Included in the Prior Art Database: 2005-Feb-14
Resistors on printed circuits are normally trimmed by removing resistor material by a series of longitudinal laser cuts. Here a fusible link is added to an assembled card by making two adjacent laser cuts across a conductor, each starting at a conductor edge to form a narrow current path. The best way to form a fusible link on a PCB is to form it when the raw card is etched. To form a fusible link by etching becomes very difficult if not impossible once the card has been populated. A method to form a fusible link after the card has been populated is based on the laser trimming process used to trim film resistors, but instead of trimming resist, a copper track is trimmed. The figure shows a copper conductor with two laser cuts, one from the left edge and one from the right edge, forming a narrow current path between.