Patent ID: 6222629
Filing Date: 2001-04-24
Classification: G01B,H05K

Abstract:
A method for inspecting a component with leads to determine fitness of the component for assembly in conjunction with automatic circuit board assembly performed using an assembly robot before the component is placed on a circuit board, said component having a row of at least two leads to be inserted into corresponding holes in the circuit board, said robot being equipped with a gripper for taking hold of the component, the method comprising:directing a narrow illuminating beam at a light-sensitive detector,translating the component and the illuminating beam in relation to each other in a direction of at least one of a width and length of the row of leads so that position of the component is known as a function of time and so that the leads of the component pass through the illuminating beam, the illuminating beam thus reaching the light-sensitive detector when passing between the leads, and the leads casting a shadow when the illuminating beam illuminates one of the leads, preventing the beam from reaching the light-sensitive detector,recording a pulse produced by the light-sensitive detector when the illuminating beam is intercepted by the one of the leads,computing, based on the pulse, at least one of a lead row width and a distance between adjacent leads rows,comparing the at least one of the lead row width and the distance between adjacent leads rows with a specified allowed respective limit, andplacing the component on the circuit board when the computed at least one of the lead row width and the distance between adjacent lead rows is within the allowed respective limit, and rejecting and removing the component without placing the component on the circuit board when the computed at least one of the lead row width and the distance between adjacent lead rows differs from the allowed respective limit.