| 摘要 |
<p>PURPOSE:To obtain a high resolution type magnetic sensor by adding a simple slit shield plate to a conventional magnetic sensor. CONSTITUTION:An exciting coil 13, detection coils 14 and 14', a shield plate 15, magnetic markers 11 and 11', and slit shield plates 16 and 16' are provided. Part of magnetic flux produced by the coil 13 is terminated by the shield plate 15 provided on both sides for the markers 11 and 12 of the magnetic sensor and never appears on the reverse surface. The magnetic flux appears outside a sensor housing only through a slit opening part to magnetize the markers 11 and 11' provided on the reverse surface. When the width of the slit is reduced, the intensity of a magnetic field becomes weak, but an area which is magnetized nearly corresponds to the slit width, so a sensor detection voltage determined by the quantity of integration of the magnetic marker surface (area which is magnetized) varies greatly with deviation in the sensor position of unit length. Therefore, the resolution when the pattern array of the magnetic markers arranged in a cord shape is improved as compared with when a magnetic sensor having no slit is used.</p> |
