Patent ID: 6154038
Filing Date: 2000-11-28
Classification: G01R

Abstract:
An apparatus for testing a circuit board having wiring patterns and traces with pads, comprising:a means for holding said circuit board;a means for detecting the electrical characteristics of said circuit board, having a conductive path between a position corresponding to a first test pad on one of said traces and a first power source as well as a second conductive path between a position corresponding to a second test pad on another of said traces and ground potential;a means for controlling a first laser plasma switch in a first space between said first test pad and said first conductive path and a second laser plasma switch in a second space between said second test pad and said second conductive path, said first and second laser plasma switches being activated with laser beams to make said first and second spaces conductive;an electrical characteristic value sampling means included in said electrical characteristics detection means and connected to one of said first and second conductive paths; anda sealing means for sealing a space between a photoconductive sheet or glass plate and said circuit board, and the sealed space is filled with a pressurized or depressurized air or rare gas,wherein said laser plasma switch control means makes said first and second spaces conductive, and a predetermined time thereafter, said electrical characteristics detection means drives said sampling means to detect an electrical characteristic value in said conductive paths.