| 摘要 |
<p>PROBLEM TO BE SOLVED: To surely detect the presence or absence of a patient on a bed, for example, without giving a feeling of physical disorder to the patient. SOLUTION: This device has a detecting sheet 20 having a primary coil 22 and a secondary coil 23 flatly formed on a soft electrically insulating sheet 21, respectively, a signal generating source 10 for applying an a.c. signal of a prescribed frequency to the primary coil 22, and an output part 30 for comparing the induced voltage induced in the secondary coil 23 by the magnetic flux generated from the primary coil 22 with a preset threshold voltage, and outputting a pulse wave according to the magnitude relation. The change portion of the mutual inductance between the primary coil and the secondary coil influenced by the access and separation of a human body is converted into the duty ratio of pulse wave to detect the presence or absence of the human body.</p> |
