Magnetic field generator and assembling method thereof

A magnetic field generator comprising:

• a pair of plate yokes opposed to each other with a space in between the plate yokes;
• not more than two supporting yokes magnetically connecting the plate yokes;
• a permanent magnet disposed on a main surface of each plate yoke, the respective main surfaces of the plate yokes being opposed to each other;
• a first shielding magnet and a second shielding magnet provided respectively at a forward portion on an open side and at a rearward portion, of another main surface, in at least one of the plate yokes;
• a first spacer placed between the plate yoke and the first shielding magnet;
• and
• a second spacer placed between the plate yoke and the second shielding magnet.

A magnetic field generator comprising:

• a pair of plate yokes opposed to each other with a space in between the plate yokes;
• a permanent magnet disposed on a main surface of each plate yoke, the respective main surfaces of the plate yokes being opposed to each other;
• a shielding magnet provided on another main surface, in at least one of the plate yokes;
• a spacer placed between the plate yoke and the shielding magnet;
• and
• a cover member provided over only the shielding magnet or fixed to the plate yoke.

A magnetic field generator comprising:

• a pair of plate yokes opposed to each other with a space in between the plate yokes;
• a permanent magnet disposed on a main surface of each plate yoke, the respective main surfaces of the plate yokes being opposed to each other;
• a shielding magnet provided on another main surface, in at least one of the plate yokes;
• a spacer placed between the plate yoke and the shielding magnet;
• and
• a nonmagnetic leg formed on said another main surface of the plate yoke on which the shielding magnet is provided.

A magnetic field generator comprising:

• a pair of plate yokes opposed to each other with a space in between the plate yokes;
• a permanent magnet disposed on a main surface of each plate yoke, the respective main surfaces of the plate yokes being opposed to each other, wherein between the permanent magnets of the plate yokes is a uniform magnetic field space formed;
• a supporting yoke magnetically connecting the plate yokes and providing a continuous open space having an opening angle not smaller than 150 degrees as viewed from a center of the uniform magnetic field space between the permanent magnets;
• a shielding magnet provided correspondingly to the open space, on another main surface, in at least one of the plate yokes, wherein the plate yoke has a gradually decreasing thickness, with said another main surface of the plate yoke having a sloped surface, the shielding magnet being provided on the sloped surface;
• and
• a spacer placed between the plate yoke and the shielding magnet.

A magnetic field generator comprising:

• a pair of plate yokes opposed to each other with a space in between the plate yokes;
• a permanent magnet disposed on a main surface of each plate yoke, the respective main surfaces of the plate yokes being opposed to each other, wherein between the permanent magnets of the plate yokes is a uniform magnetic field space formed;
• a supporting yoke magnetically connecting the plate yokes and providing a continuous open space having an opening angle not smaller than 150 degrees as viewed from a center of the uniform magnetic field space between the permanent magnets;
• a shielding magnet provided correspondingly to the open space, on another main surface, in at least one of the plate yokes, wherein a magnetic field not smaller than 0.3 T is generated in the uniform magnetic field space;
• and
• a spacer placed between the plate yoke and the shielding magnet.