| 摘要 |
An instrument for measurement of thickness of a non-magnetic layer on a magnetic or magnetizeable substrate including a permanent magnet having a test pole which is resting against the non-magnetic layer and an opposite pole, a comparison body arranged at a distance from the opposite pole, a mechanism for adjusting the spacing of the comparison body from the opposite pole until the magnetic fields between the comparison body and the opposite pole and between the substrate and the test plate are equal and a device for displaying such spacing. In this manner, the gap between the comparison body and the opposite pole of the magnet becomes the same as the spacing between the test pole and the substrate which is the thickness of the non-magnetic layer. Different embodiments are presented. In three of the embodiments, when the magnetic fields become equal at both poles of the magnet, the magnet moves away from the non-magnetic substrate. In the fourth embodiment, the actual magnetic fields are measured and when they become equal, a drive mechanism which moves the comparison body towards the opposite pole is disengaged.
|
