| 摘要 |
The outer circumference of an encoder (4) has its inner and outer half portions formed into first and second characteristic changing portions (9, 10), in which the directions of inclination of characteristic boundaries are different from each other. Three circumferential portions of those two characteristic changing portions (9, 10) are individually confronted by detecting units of pairs of sensors (6a<SUB>1</SUB> (6b<SUB>1</SUB>, 6c<SUB>1</SUB>)) and (6a<SUB>2</SUB> (6b<SUB>2</SUB>, 6c<SUB>2</SUB>)). Moreover, a not-shown functional unit is given a function to compute displacements (x, y, z) and inclinations (?<SUB>x</SUB>, ?<SUB>z</SUB>) on the basis of the phase differences existing between the output signals of those individual sensors (6a<SUB>1</SUB>, 6a<SUB>2</SUB>, 6b<SUB>1</SUB>, 6b<SUB>2</SUB>, 6c<SUB>1</SUB>, 6c<SUB>2</SUB>). |
