| 摘要 |
PURPOSE:To prevent the generation of error pulses caused by the play of a slit plate and the backlash of a transmission gear by detecting the rotating position of the slit plate through 2 detectors with different detection phases. CONSTITUTION:A slit plate 6 includes the 1st slit group 10 and the 2nd slit group 11. The number of slits 10a and 11a is the same in both the slit groups 10 and 11 and the slit 10a is shifted to the rotating direction of the slit plate 6 by a half of the slit width from the slit 11a. At the rise and decay time of the output of the 2nd detector 8 to detect the slit 11a, a pulse signal with the level corresponding to the output of the detector 7 to detect the slit 10a is outputted. It may be also available to attach 2 detectors to one slit group with the shift of a half of the slit width. |
