| 摘要 |
PURPOSE:To avoid the error caused by the deviation of the center when a code plate is attached to a rotary shaft, by arranging the position of a slit on the radius separated from the center of the rotary shaft by a specified distance. CONSTITUTION:An annular light shielding film 4-2 having a certain width is attached to a disk 4-1 concentrically with a central hole 4-4 of the disk 4-1. The disk 4-1 is fixed to a rotary shaft 2. Then the rotary shaft 2 is mounted to a chuck 12 of a slit machining apparatus. Under this state, a motor 10 is rotated, a pulse signal which is proportional to the motor speed, is generated by a pulse generator 11 and fed back to a control device 16, and the speed of the motor 10 is stabilized. The pulse signal is applied to a laser light emitting device 15 through a laser light emission control device 17, and the timing and output of the laser light emission are controlled. The laser light 15-1 is projected on the radius of the light shielding film 4-2 of the code plate 4. The position is separated from the center of the rotary shaft by a specified distance. At this time, intervals are provided in the pulse shaped laser light so as to have a specified relationship with the output pulses of the pulse generator. Then the light shielding film 4-2 is melted and a slit is formed. |
