US Patent 7656175 Inspection unit

An insulative block has a first face adapted to oppose a board on which an inspection circuit is arranged and a second face adapted to oppose a device to be inspected. The insulative block is formed with first through holes each of which communicates the first face and the second face. A conductive first plating layer is formed on the first face, the second face, and an inner face of at least one of the first through holes. Each of contact probes includes a conductive tubular body held in an associated one of the first through holes and a plunger which is retractably projected from one end of the tubular body and is adapted to come in contact with a terminal of the device.