Charged particle beam scanning device

Abstract

A plurality of control plates are sandwiched between a cathode and a target to control the flow of charged particles such as electrons and ions between the cathode and the target. Each control plate has a plurality of apertures formed therein which are effectively aligned with corresponding apertures on the other control plates. At least one input buffer plate and one output buffer plate are sandwiched between the control plates and the cathode and target respectively. The input buffer plate and the output buffer plate have a plurality of apertures formed therein aligned with corresponding apertures in the control plates. The aligned apertures form beam channels. The control plates have conductive electrodes thereon arranged at predetermined coded finger patterns. D.C. voltages are applied to the buffer plates to provide electron optic lensing and voltages are selectively applied to the control plate electrodes by switching circuitry to selectively open and close beam channels. The separation of the buffer plates from the control plates is by anomalously thick spacer plates to isolate the control plates from the high voltages associated with the buffer plates. By selective switching control of the control plates a beam, or a plurality of beams, can be directed to a selected portion or portions of the target at a time.