Consideration about Novel Proximity Sensing Technique Applying Quasi Electric Field Generated by Multipole Electrodes Structure

Among the three components of electromagnetic field (radiated field, induced field and quasi electrostatic field (QEF)), the QEF has a characteristic of decaying proportional to cube of the distance. Regardless of the QEF's potential characteristics, QEF has been treated as unimportant in the past. In this paper, we developed a novel proximity sensing technology applying QEF. Noncontact and noninvasive object sensing is realized by using equilibrium of QEF distributions generated with the multiple electrodes structure. From results of electromagnetic simulation and experimental analysis, we clarified our method can improve the detection resolution of conventional proximity sensing method drastically, because the detection resolution in our method doesn't depend on QEF frequency generated by quadrupole electrodes, but depends on the parameter of the gap size between each electrode. Finally, we focused on human vein sensing, as one of the most important application example of our technique, which is well known as a biometrics technology. From the electromagnetic simulation, we confirmed our method is applicable to the vein sensor by using the matrix array structure of the fundamental element of quadrupole electrodes.