| 摘要 |
PROBLEM TO BE SOLVED: To correct a defective opening of a shadow mask and to improve the yield. SOLUTION: The device of this invention comprises a horizontal fine deflecting circuit 17, a vertical fine deflecting circuit 18, and a cathode driver 16. A fine deflecting current in which bipolar pulse current is superimposed on a direct current is made to flow through a horizontal coil 8 and a vertical coil 15 of a deflecting yoke under the control of a control unit 1, a defective opening to which a foreign matter is attached is searched and detected, and pulse current of high energy is applied to the cathode of an electron gun by a cathode driver 16 to remove the foreign matter.
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