Patent ID: 7969145
Filing Date: 2011-06-28
Classification: B82Y,G01B,G01R

Abstract:
1. A position detecting device comprising: a fixed member; and a movable member being movable relatively to the fixed member, a magnet provided in one of the fixed member and the movable member, a detector that detects a magnetic field generated from the magnet being provided in the other member, wherein the magnet has a front surface that faces the detector, wherein the front surface and a rear surface of the magnet are magnetized to different magnetic poles, wherein the detector includes a detecting element that detects horizontal components of magnetic flux running from the front surface to the edge of the magnet, wherein the distance between the front surface of the magnet and the detector gradually increases from the center of the magnet to the edge of the magnet, wherein the detector includes an X direction detecting element that detects an X-direction component among the horizontal components of the magnetic flux and a Y direction detecting element that detects a Y-direction component orthogonal to the X-direction component, wherein the front surface of the magnet has a circular shape, and wherein the distance between the detector and the front surface of the magnet gradually increases from the center to the edge of the magnet in all directions from the center to the edge of the magnet.