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Method and apparatus for evaluating multilayer objects for imperfections patent application
- ""Precision design of high speed circuits demands secure mounting of components. Multilayer ceramic capacitors serves this function, but often contain critical defects. Current nondestructive evaluation techniques are severely limited. The present invention permits an evaluation of such objects. A multilayer object comprising multiple layers arranged in a stacking direction is evaluated for imperfections such as voids, delaminations and microcracks. First, an acoustic wave is transmitted into the object in the stacking direction via an appropriate transducer/waveguide combination. The wave propagates through the multilayer object and is received by another transducer/waveguide combination preferably located on the same surface as the transmitting combination. The received acoustic wave is correlated with the presence or absence of imperfections by, e.g., generating pulse echo signals indicative of the received acoustic wave, wherein the successive signals form distinct groups over time. The respective peak amplitudes of each group are sampled and curve fit to an exponential curve, wherein a substantial fit of approximately 80-90% indicates and absence of imperfections and a significant deviation indicates the presence of imperfections. Alternatively, the time interval between distinct groups can be measured, wherein equal intervals indicate the absence of imperfections and unequal intervals indicate the presence of imperfections. Novel aspects of the present invention include use of acoustic waves to nondestructively evaluate a multilayer object and the analytical methods employed to evaluate the object for imperfections."--P. i."
- "Method and apparatus for evaluating multilayer objects for imperfections patent application"@en
- "Method and apparatus for evaluating multilayer objects for imperfections"