Patent ID: 8084929

Claim:
A system that focuses electron beams in an electro-static area, comprising: a housing assembly arranged to define a first interior portion and an opening through which an electron beam exits said first interior portion; a field forming cathode electrode system arranged in said first interior portion, said field forming cathode electrode system comprising a cathode assembly and a near-cathode electrode system, said cathode assembly comprising a cathode having a front surface with a flat form, and said near-cathode electrode system comprising: a flat part that is at the same level as said flat front surface of said cathode, a curvilinear part which is contiguous with said flat part; and a substantially cylindrical part contiguous with said curvilinear part, said flat part of said near-cathode electrode system being spaced apart at a front surface from said cathode by a cavity and having a same potential as said cathode; a focusing electrode system arranged in said first interior portion and spaced apart from said field-forming cathode electrode system, said field-forming cathode electrode system and said focusing electrode system constitutes a source for forming an electron beam; and an anode electrode system arranged in said first interior portion on an opposite side of said focusing electrode system from said field forming cathode electrode system, said anode electrode system being arranged such that the electron beam passes therethrough, said anode electrode system including at least one anode, said focusing electrode system including at least one opening through which the electron beam passes between said field forming cathode electrode system and said anode electrode system, said focusing electrode system including at least two focusing electrodes each including a curvilinear part.