Contactless inspection of planar electronic devices by capacitive coupling: Development of a model describing the sensor signal and its impact on signal post-processing

With regard to a contactless inspection method for planar electronic devices, a model to derive the signal of the employed sensors has been developed. The measurement technique is exclusively based on capacitive coupling and, for instance, applied to the inspection of flat panel displays (FPDs) and printed electronics. To analyze the sensor signals, to evaluate the sensor performance, and to advance signal post-processing, a model of the capacitive coupling is essential. Focussing on configurations of conductor tracks arranged in parallel, the model approach is explained and illustrated in detail. Finite element (FE) simulations and measurements are used to derive the model parameters, to validate the model approach, and to evaluate the model performance. Possible applications to signal post-processing are discussed. As an example, the model is used to reconstruct the voltages applied to individual tracks of a configuration from the sensor signal. Furthermore, the model is extended to configurations of two-dimensionally arranged conductor tracks.