Patent ID: 8547636
Filing Date: 2013-10-01
Classification: G02F

Abstract:
1. A permanent magnet structure comprising: an axially symmetric housing surrounding an axial clear aperture along a central axis; a longitudinally magnetized axial high-strength permanent magnet surrounding the axial clear aperture within the housing; at least one set of at least two radial magnet sectors disposed adjacent said axial magnet, the magnet sectors having radially aligned magnetization wherein inner surface magnetic poles are aligned to be the same as the pole of the adjacent surface of said axial magnet; said housing having an outwardly tapered inner section in the region of the at least one set of radial permanent magnet sectors for allowing radial tilting of the magnet sectors; and an endplate displaceably attached in the end of the housing and disposed abutting the at least one set of radial magnet sectors, the endplate being translatable along the central axis to effect radial tilting of the abutted adjacent radial magnet sector set into the tapered section of said housing thereby tuning the strength of longitudinally directed fields in the region in and near the axial magnet inner surface.