Patent attributes
An absolute encoder configured to, when a rotation range of a measurement target member is limited by a brake mechanism, generate an AB-phase signal and a Z-phase signal for calculating a rotation angle of the measurement target member. The absolute encoder includes a brake mechanism, a plurality of Z-phase-signal-detection-target portions each having a Z-phase-signal-rise-detection-target portion and a Z-phase-signal-fall-detection-target portion, a plurality of AB-phase-signal-detection-target portions each located between a Z-phase-signal-rise-detection-target portion and a Z-phase-signal-fall-detection-target portion that are adjacent to each other in a circumferential direction, to thereby form a plurality of restriction ranges each including at least one of the Z-phase-signal-rise-detection-target portions and at least one of the Z-phase-signal-fall-detection-target portions. An interval in the circumferential direction between a Z-phase-signal-rise-detection-target portion and a Z-phase-signal-fall-detection-target portion that are adjacent to each other in the circumferential direction is different among the plurality of restriction ranges.