| 摘要 |
AN ELECTRON GUN (17) COMPRISES A SUPPLEMENTARY GRID (SG) APPLIED WITH A VOLTAGE WHICH DYNAMICALLY CHANGES IN SYNCHRONIZATION WITH A MAGNETIC FIELD GENERATED BY A DEFLECTION YOKE, BETWEEN A SECOND GRID (G2) AND A THIRD GRID (G3). FURTHER, BY THE SECOND GRID (G2) AND A THIRD GRID (G3). FURTHER, BY THE SECOND GRID (G2), THE SUPPLEMENTARY GRID (SG), AND THE THIRD GRID (G3), AN ELECTRON IS CONSTRUCTED WHICH HAS AN ASTIGMATIC ABERRATION IN WHICH A FOCUSING FORCE IN THE HORIZONTAL DIRECTION IS STRONGER THAN A FOCUSING FORCE IN THE VERTICAL DIRECTION. THE INTENSITY OF THE ASTIGMATIC ABERRATION OF THE ELECTRON LENS IS DYNAMICALLY CHANGED BY A VOLTAGE APPLIED TO THE SUPPLEMENTARY GRID.(FIG. 4)
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