Charged particle beam scanning device

An electron beam scanning device comprising;

• an electron flood gun for providing a uniform flow of electrons over a predetermined area, said electron flood gun including a flat dish, a first electrode having a negative potential on said flat dish, a plurality of elongated filaments for generating electrons positioned in front of said first electrode, and a second electrode having a positive potential on said flat dish interdigitated with said second electrode,
• an area target,
• a plurality of control plates sandwiched between said source and said target for controlling the flow of electron therebetween, each of said control plates having a plurality of apertures formed therein, corresponding apertures of said control plates being aligned to form electron beam channels between the source and the target, said control plates each having a plurality of electrodes on at least one of the surfaces thereof, said electrodes on each of said surfaces being electrically insulated from each other,
• means for providing potentials to at least one of the electrodes of each successive control plate to focus said electrons through selected control plate apertures,
• and means for providing a cutoff potential to the remaining electrodes of said control plates,
• whereby a beam of electrons is focused by said focusing potentials through the channels formed by said selected apertures.

An electron beam scanning device comprising;

• an electron flood gun for providing a uniform flow of electrons over a predetermined area, said electron flood gun including a flat plate, a first electrode positioned on said flat plate, said first electrode formed in a series of elongated parallel fingers, a second electrode positioned on said flat plate insulated from said first electrode, said second electrode formed in a series of parallel fingers interdigitated with said first electrode, a plurality of elongated filaments for generating electrons, positioned in front of each finger of said first electrode,
• means for applying a negative potential to each of the fingers of said first electrode and a positive potential each finger of said second electrode,
• an area target,
• a plurality of control plates sandwiched between said source and said target for controlling the flow of electrons therebetwee, each of said control plates having a plurality of apertures formed therein, corresponding apertures of said control plates being aligned to form electron beam channels between the source and the target, said control plates each having a plurality of electrodes on at least one of the surfaces thereof, said electrodes on each of said surfaces being electrically insulated from each other,
• means for providing potentials to at least one of the electrodes of each successive control plate to focus said electrons through selected control plate apertures,
• and means for providing a cutoff potential to the remaining electrodes of said control plates,
• whereby a beam of electrons is focused by said focusing potentials through the channels formed by said selected apertures.