Patent ID: 7167067
Filing Date: 2007-01-23
Classification: G01R

Abstract:
1. A magnetic field generating device comprising: a plurality of magnet elements arranged in a ring shape such that a magnetization direction of the magnet elements undergoes one rotation over half a circumference of the ring, wherein the magnet elements generate a substantially unidirectional magnetic field in a space within the ring; and one or more corrective magnets arranged only on an outer edge portion and not on a lateral surface on an inner circumferential surface of said magnetic field generating device, wherein an aperture is formed in a Z-axis direction of the magnetic field generating device, wherein the Z-axis is defined as a central axis of the magnetic field generating device, the Y-axis is defined as a direction perpendicular to the Z-axis and parallel to the unidirectional magnetic field, and the X-axis is defined as a direction perpendicular to the Z-axis and the Y-axis.