| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a proximity sensor capable of reducing an eddy current loss and obtaining necessary and sufficient position detection sensitivity even if detection coils are covered by an outer shell made of metal. <P>SOLUTION: A proximity sensor having an excellent S/N ratio and high sensitivity can be realized, after rectangular wave voltages are applied to two coils, not by independently detecting an electric current flowing in each of the coils and then calculating differences at a differential circuit or the like, but rather by directly detecting values of differences between electric currents. The respective coils have the same magnetic characteristics and electric characteristics, thereby changing in the same way even if these characteristics are changed by temperature change. Therefore, variation caused by the temperature change hardly occurs. <P>COPYRIGHT: (C)2012,JPO&INPIT |
