POSITION DETECTION APPARATUS, LENS APPARATUS, IMAGE PICKUP SYSTEM, MACHINE TOOL APPARATUS, POSITION DETECTION METHOD, AND NON-TRANSITORY COMPUTER-READABLE STORAGE MEDIUM WHICH ARE CAPABLE OF DETECTING ABNORMALITY

摘要

A position detection apparatus (100) which detects a position of an object includes a scale (2) including a periodic pattern, a detector (7) configured to be movable relative to the scale, and a signal processor (101) configured to acquire position information of the object based on a first output signal from the detector and perform abnormality determination based on a second output signal from the detector, a spatial frequency response of the first output signal is peaked at a first spatial frequency, and a spatial frequency response of the second output signal is peaked at a second spatial frequency different from the first spatial frequency.

主权项

1. A position detection apparatus which detects a position of an object, the position detection apparatus comprising:
a scale including a periodic pattern; a detector configured to output a first output signal and a second output signal, the detector and the scale being relatively movable each other; and a signal processor configured to acquire position information of the object based on the first output signal from the detector and perform abnormality determination based on the second output signal from the detector, wherein: a spatial frequency response of the first output signal is peaked at a first spatial frequency, and a spatial frequency response of the second output signal is peaked at a second spatial frequency different from the first spatial frequency.