MEASUREMENT OF OBJECT LAYER THICKNESS USING ULTRA-SONIC METHODS AND DEVICES

摘要

The present invention provides for a method of measuring layer thickness in an object comprising transmitting at least a first and a second ultra-sonic pulse from at least a first and second position; measuring at least one reflective distance from the first pulse and at least one reflective distance from the second pulse, wherein the reflective distance is from the object's external surface (or probe) to a reflective interface (5) of at least one layer; selecting the reflective distance having the shortest reflective distance to indicate the distance between the external surface (or probe surface) and the reflective interface (5) of at least one layer, wherein the selecting of the shortest reflective distance reduces ultra-sonic transmission parallax of the first and second pulses relative to a plane (4) in the object.