| 摘要 |
PROBLEM TO BE SOLVED: To realize an inspection method which can precisely measure the magnetic flux density and pitch errors of an encoder 7a, even when the detectable magnetic flux density of the encoder 7a is small, similar to the case in which an air gap is large. SOLUTION: The magnetic flux density of the encoder 7a is detected by a Hall sensor 9, having a Hall device incorporated therein and by an MR (magnetoresistive) sensor 10, having an MR element incorporated therein. The MR sensor 10 has a large output voltage, even if the detectable magnetic flux density is small, when it is compared with the Hall sensor 9, and the effect due to the temperature variations is small. Accordingly, even if the detectable magnetic flux density is small, the pitch of the encoder 7a can be measured accurately. Further, the magnitude of the magnetic flux density of the encoder 7a can be also measured by the Hall sensor 9, capable of measuring the magnitude of the magnetic flux density, by detecting the magnetic flux density of the encoder 7a. COPYRIGHT: (C)2006,JPO&NCIPI
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