| 概要 | Various types of sensors are used for foreign object detection. Among them, capacitive sensors, which detect changes in capacitance, are relatively easy to design and can provide sufficient detection accuracy. This example evaluates the operation of a foreign object detection sensor by analyzing the change in capacitance between opposing interdigitated electrodes with and without a foreign object. |
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| モデル解説 | Figure 1 shows the analysis model. Two interdigitated electrodes are arranged opposite each other on a substrate. A voltage boundary condition is applied to one electrode, while the other electrode is assigned a 0 V boundary condition and treated as a ground (GND) electrode. |
| 結果解説 | First, an electrostatic capacitance analysis is performed without a foreign object. Figure 2 shows the resulting electric potential distribution. The capacitance between the electrodes is found to be 5.6 pF. Next, Figure 3 shows the analysis model with a foreign object present. The foreign object is modeled as a dielectric material with a specified relative permittivity. Figure 4 shows the analysis result. When the foreign object is present, the capacitance between the electrodes increases to 6.3 pF. Because the capacitance between the electrodes changes depending on the presence or absence of the foreign object, the model is confirmed to operate as a foreign object detection sensor. |
| キーワード | Foreign Object Detection Sensor, Capacitive Sensor, Interdigitated Electrodes, Capacitance Analysis, Dielectric Material, Sensor Sensitivity Design |
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Figure 2
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Figure 4
