CORPUSCULAR BEAM DEVICE HAVING ENERGY FILTER

PROBLEM TO BE SOLVED: To provide a corpuscular beam device in which a corpuscular beam used for forming an image can have a high energy sharpness, and in which Boersch effect is less. SOLUTION: This corpuscular beam device has a dispersion image forming energy filter 7 in an illumination light path. Energy sharpness of particles contributing to corpuscular optical image formation is improved, and formed image color error is reduced by this. For preventing move of an image of a beam generator 1, 1a caused by voltage fluctuation of impressed high voltage in spite of dispersion generated after complete pass through the filter 7, the beam generator 1, 1a is enlarged to form an image on a flat surface 9 of the filter 7, and an image is formed on an output side image plane 10 in a decolored condition. Dispersion of a dispersion filter is strong compared to that of a non-dispersion filter, so this corpuscular beam device can be operated even when a particle energy inside the filter 7 is high, thereby Boersch effect is reduced compared to the case of the non-dispersion filter.