| 摘要 |
PURPOSE:To dynamically change the intensity of a comprehensive magnetic field electron lens, by obtaining a substantially coincident peak position of distribution of the magnetic field constructed from the main magnetic field produced by a permanent magne and the auxiliary magnetic field procuced by a solenoid coil. CONSTITUTION:An electron lens comprises a permanent magnet 31 and yoke 32, for producing the main magnetic field, solenoid coils 34, 35, for producing the auxiliary magnetic field and synchronizing with the horizontal deflection to dynamically focus a beam, and a solenoid coil 36 synchronizing with the vertical deflection to dynamically focus a beam further generate the DC magnetic field. Further a current of saw tooth-shaped waveform flowing in a transistor 41 in a horizontal deflection circuit and current flowing in a damper diode 42 are allowed to flow in the coil 34 and the coil 35 respectively, then the dynamically focusing operation is performed simultaneously with the horizontal deflection of a beam. In this way, an electron lens, for attaining an optimum spot beam simultaneously requiring less quantity of circuit parts further with less consumption of the electric power, can be obtained. |
