Patent ID: 7315164
Filing Date: 2008-01-01
Classification: G01D,G02B,G03B,H02N

Abstract:
1. A drive unit comprising: a magnetic field generating member for generating a magnetic field; a magnetic field detecting device including first, second and third magnetic field detecting elements for detecting the magnetic field; a driving device for moving the magnetic field generating member or the magnetic field detecting device; and the drive unit executing a relative positioning between the magnetic field generating member and the magnetic field detecting device on the basis of a detection result by the magnetic field detecting device, wherein a first positioning is executed on the basis of the detection result of the first and second magnetic field detecting elements in a predetermined region, and a second positioning is executed on the basis of the detection result of the third magnetic field detecting element at a predetermined point apart from the predetermined region, within a movable range in which the magnetic field generating member or the magnetic field detecting device moves.