METHOD FOR NON-DESTRUCTIVELY INSPECTING PIEZO-ELECTRIC ELEMENT FOR MICRO-CRACK

摘要

PURPOSE: To obtain an method for non-destructively inspecting piezo-electric elements for micro-cracks by which the presence/absence of micro-cracks in a piezo-electric element can be quickly and automatically discriminated with high accuracy. ;CONSTITUTION: The frequency characteristics of the phase difference (phase angle) between the frequency characteristic and/or voltage and current of the impedance of a piezo-electric element is measured and the curve pattern indicating the measured frequency characteristics is compared with the curve pattern of the element which is used as a reference and, when both curve patterns are different from each other, it is discriminated that micro-cracks exist in the element. Since the presence of the micro-cracks can be discriminated automatically, the discrimination can be performed in a short time and mass processing become possible. In addition, the inspection accuracy becomes extremely higher, since no visual inspection is performed.;COPYRIGHT: (C)1994,JPO&Japio