MAGNETIC CIRCUIT DEVICE FOR ELECTRON LENS

文件类型：PDF文档
文件大小：71K
PROBLEM TO BE SOLVED : To provide a magnetic circuit device for electronic lens capable of generating a magnetic field nearly uniform in the lens axial direction. SOLUTION : The magnet circuit device has, on the inner peripheral side of a cylindrical yoke 2 having an axial line Z coinciding with a lens axis, a first magnet unit 3a having a plurality of magnet bodies 31a, 32a, 33a composed of permanent magnets magnetized in the radial direction, and a second magnet unit 3b which is arranged symmetrically about a center line X orthogonal to the axial line Z in the longitudinal cross-section containing the axial line and has a plurality of magnet bodies 31b, 32b, 33b composed of permanent magnets magnetized in the reverse polarity to the magnet bodies 31a, 32a, 33a constituting the first magnet unit 3a. The magnet bodies 31a, 32a may be formed of a rare earth sintered magnet, and the magnet body 33a may be formed of a ferrite sintered magnet. COPYRIGHT : (C)2010, JPO&INPIT