| 摘要 |
PURPOSE:To simplify the fitting by making the shape of a deflecting magnetic field control element specific. CONSTITUTION:Electron beam passing holes 10A-10C are arranged on a straight line, and deflecting magnetic filed control elements 9A, 9B are arranged around the holes 10A, 10C respectively. The elements 9A, 9B both surround the holes 10A, 10C and are formed with a frame-shaped section 91 having an open section 911 in the arranged direction of the passing hole and a straight line section 92 straightly extended in the arranged direction of the passing hole. The elements 9A, 9B are arranged so that their open sections 911 are located on the outside, and the sizes of the frame-shaped section 91 and the straight line section 92 are set to the required values. According to this arrangement, the vertical deflecting magnetic field enters to the inside through the open section 911, the horizontal deflecting magnetic field becomes coarse, and the deflecting magnetic field can be simply controlled without being bothered with the adjustment of the arrangement position of the deflecting elements.
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