Linear motor, movable stage and electron microscope

摘要

It is an object to balance suppression of a leakage magnetic field and driving performance. In a linear motor including a stator including a first yoke having an open face and two rows of permanent magnets linearly arrayed inside the first yoke so that S-poles and N-poles are alternate and a movable element arranged between the two rows of permanent magnets and linearly moving, a second yoke is connected to an open end of the first yoke so as to cover the open end of the first yoke and the permanent magnets when viewed from the open face of the first yoke.

主权项

1. A linear motor comprising:
a stator including a first yoke made of ferromagnetic substance and having an open face and two rows of permanent magnets linearly arrayed inside the first yoke so that S-poles and N-poles are alternate; and a moveable element arranged between the two rows of permanent magnets and linearly movable in a moving direction; the stator is constructed by connecting a plurality of separated stators along with the moving direction of the movable element; the two rows of permanent magnets are provided from an opening face of the open face of the first yoke and spaced apart from each other in a direction perpendicular to the moving direction of the movable element; a second yoke made of ferromagnetic substance and in a form of two stick-shaped members and/or a plate member in a square shape surrounding an entire periphery of an open end of the first yoke and provided along the connecting direction of the separated stators, wherein the stick members and/or the plate member and the two rows of permanent magnets are provided to face each other at the open end of the first yoke selectively to provide a smaller opening space than the opening space of the open face of the first yoke, in a direction perpendicular to the moving direction of the movable element, wherein the first yoke and the second yoke are connected by an adhesive connecting member, or a magnetic force from each other.