Multi-apertured single plate matrix lens

A matrix lens for finely focussing a collimated electron beam upon a surface of a target, comprising:

• a single plate having an array of apertures formed therethrough;
• said plate being maintained in spaced and substantially parallel relation to said target surface;
• said electron beam passing through a selected one of said apertures toward said target;
• each said aperture being associated with one of a plurality of areas defined upon said target surface;
• a hollow member having a pair of opposed parallel and planes, a first end plane substantially abutting said target surface and another end plane substantially abutting a surface of said single plate facing said target surface and another end plane substantially abutting a surface of said single plate facing said target surface, the bore of said member being aligned to facilitate passage therethrough of said electron beam passing through any of said apertures;
• and
• a series of spaced rings of conductive material formed upon the interior surface of said member with the plane of each said ring being substantially parallel to the plane of said target and said plate, each of said rings having an electrical potential impressed thereon of magnitude increasingly greater in a direction toward said target to cause formation of an electrostatic field within at least a portion of the volume enclosed by said rings and essentially orthogonal to a surface of said plate facing said target;
• said electrostatic field having a magnitude causing electrons of said beam to be continuously accelerated toward said target.