Patent ID: 9733317
Date: 2017-08-15
CPC Classifications: G01D,G01R

Claim:
1. A position detecting device, comprising: a scale having a magnetic signal with a constant period magnetically recorded on a magnetic medium; a detecting section having a plurality of magnetism detecting elements configured to detect a leakage magnetism from the magnetic signal of the scale and output signals corresponding to the magnetic signal at positions where the leakage magnetism has been detected; and a position detecting section configured to detect a position relative to the scale based on the signals output by the plurality of magnetism detecting elements of the detecting section, wherein the plurality of magnetism detecting elements of the detecting section are arranged, along a detection direction of the magnetic signal of the scale, in a pattern with a pitch of 1/2n (n is a prime number of three or more) of a wavelength λ′ of the signals output by the plurality of magnetism detecting elements of the detecting section, wherein as a pattern for cancelling m odd-order harmonics of the signals output by the plurality of magnetism detecting elements of the detecting section, the m-th power of two magnetism detecting elements are arranged within a range in which a pitch distance L of the two magnetism detecting elements farthest in the detection direction is expressed by L=(λ′/2)×(1/3+1/5+1/7+ . . . 1/(2m+1)) (m is an integer).