| 摘要 |
PROBLEM TO BE SOLVED: To provide an encoder device with fewer amplitude fluctuation of a signal output from a photodetector capable of measuring an amount of rotation with high accuracy, even when a space between a rotation plate and a fixing plate fluctuates. SOLUTION: On a plate 1F at a center among three plates, a slit 1FS with a pitch P is notched radially with a rotating axis as a center and equally divided by resolution in a range contributing to the output of the photodetector 5 around a point crossing with an optical axis. On a plate 1R at one side, a slit 1RS with a pitch 2P twice as much as that of the slit 1FS on the central plate 1F is notched. On a plate 2 at another side, a slit 2S with a pitch 2P twice as much as that of the slit 1FS on the central plate 1F is notched radially with the rotating axis as the center extending over a circumference thereof. The plate 2 with the slit 2S notched extending over the circumference is rotated with the rotating axis, and the plates 1F, 1R are fixed where the remaining two slits 1FS, 1RS are notched. COPYRIGHT: (C)2004,JPO
|
