Patent ID: 8669534
Filing Date: 2014-03-11
Classification: H01J

Abstract:
1. An electrostatic lens for charged particles provided with a plurality of electrodes arranged on a central axis, each of the electrodes having a through hole for passing through the charged particles, wherein among the plurality of electrodes, a plurality of electrodes arranged on an incident side of the charged particles form a first electric field area which reduces an orbit radius of the charged particles without exceeding, on the way, an initial orbit radius that is an orbit radius at an incident time of the charged particles and form a second electric field area which applies a force to advance the charged particles, which have passed through the first electric field area, to a parallel direction with the central axis, and wherein among the plurality of electrodes, a plurality of electrodes arranged on a projection side form a third electric field area which keeps the orbit radius of the charged particles not to exceed the initial orbit radius on the way and curves the orbits of the charged particles to intersect with the central axis at angles larger than orbit angles of the charged particles defined with respect to the central axis at a time of being projected from the second electric field area.