| 摘要 |
PROBLEM TO BE SOLVED: To provide a deflector generating almost no deflection chromatic aberrations. SOLUTION: In an electrostatic and electromagnetic superimposed type deflector 11, the deflection electrodes 12a, 12b of the electrostatic deflector are given voltages of different polarities and of the same magnitude by power supply devices 14a, 14b. The deflection coils 13a, 13b of the electromagnetic deflector are connected in series with each other and given currents by a power supply device 14c, whereby an electric field pointed in the direction of the hatching arrow is generated depending on the electrostatic deflector. When a charged- particle beam is an electron beam, it is deflected in the direction opposite to the black arrow. A magnetic field as indicated by void arrows is generated depending on the electromagnetic deflector. Thus when the charged-particle beam is an electron beam, it is deflected in the direction of the black arrow. By holding constant the strength ratio of the electrostatic deflector to the electromagnetic deflector, the chromatic aberrations of the electrostatic deflector and the electromagnetic deflector cancel out each other and no chromatic aberrations are generated as a whole.
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