CHARGED PARTICLE BEAM MULTI-POLE DEFLECTION CONTROL CIRCUIT

摘要

PROBLEM TO BE SOLVED: To establish a method for making the scan with a charged particle beam using of deflecting plates and a multi-polar deflection control circuit capable of mitigating such problems as noise generation and unstableness which an analog circuit involves inevitably. SOLUTION: A circuit 100 to control a multi-polar deflecting device 200 for charged particle beam includes a digital signal processor 11 which is connected with deflecting plates P1-P8 and works through cumulative arithmetic logical units ALU-1 thru ALU-8. For the scanning line to be started, the digital signal processor 11 gives signals consisting of a digital number representing the initial value (if any) and a digital number representing the step size to the respective logical units ALU-1 thru ALU-8. In each cycle of scanning clock which occurs subsequently, the logical units ALU-1 thru ALU-8 add continuously the step size to the previous cumulated value. This cumulated value depends upon the value as the sum of the initial value (if any) and the value obtained by multiplying the step size by the elapsed cycle number from the first cycle of the scanning clock.