| 摘要 |
PURPOSE:To improve characteristic by setting distribution of focusing magnetic field of a focusing coil in a predetermined range. CONSTITUTION:The distribution of focusing magnetic field of a focusing coil 25 disposed on the outside of an image pickup tube is set in the range of BT/BP=0.3-0.55 and BA/BP=0.25-0.55. Where, magnetic flux density in the target face of focusing magnetic field distribution is made Br, that in the peak position of focusing magnetic field distribution is made BP and that in the limiting aperture face of focusing magnetic field distribution is made BA. |
