Rotary encoder, rotary motor, and rotary motor system

A rotary motor comprising:

• a motor configured to rotates a rotating shaft;
• and
• a rotary encoder that is connected to the rotating shaft and configured to measures a position of the rotating shaft, wherein
• the rotary encoder comprises:
• a disk in a disk shape that is arranged rotatably about a rotation axis in association with rotation of the rotating shaft and that includes one or more tracks in a ring shape on which an optical rotating grating is formed on whole circumference and one or more origin detection areas serving as partial areas on which an optical rotating grating is formed and that are offset from the rotation axis;
• and
• a mask that is fixed and arranged in a manner facing the disk and on which two or more optical fixed gratings capable of constituting a diffraction interference optical system together with each of the rotating grating of the tracks and the rotating grating of the origin detection areas are formed, wherein
• a plurality of slits included in the rotating grating of the origin detection areas are inclined slits formed in a manner inclined in a circumferential direction with respect to radial lines about the rotation axis or curved slits curved in the circumferential direction with respect to the radial lines about the rotation axis.

A rotary motor system comprising:

• a motor configured to rotates a rotating shaft;
• a rotary encoder that is connected to the rotating shaft and configured to measures a position of the rotating shaft;
• and
• a controller configured to controls rotation of the motor based on the position detected by the rotary encoder, wherein
• the rotary encoder comprises:
• a disk in a disk shape that is arranged rotatably about a rotation axis in association with rotation of the rotating shaft and that includes one or more tracks in a ring shape on which an optical rotating grating is formed on whole circumference and one or more origin detection areas serving as partial areas on which an optical rotating grating is formed and that are offset from the rotation axis;
• and
• a mask that is fixed and arranged in a manner facing the disk and on which two or more optical fixed gratings capable of constituting a diffraction interference optical system together with each of the rotating grating of the tracks and the rotating grating of the origin detection areas are formed, wherein
• a plurality of slits included in the rotating grating of the origin detection areas are inclined slits formed in a manner inclined in a circumferential direction with respect to radial lines about the rotation axis or curved slits curved in the circumferential direction with respect to the radial lines about the rotation axis.